Bulletin of the American Physical Society
47th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 61, Number 8
Monday–Friday, May 23–27, 2016; Providence, Rhode Island
Session D1: Poster Session I (4:00pm6:00pm)Poster

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Room: Exhibit Hall C 

D1.00001: SPECTROSCOPY, LIFETIMES, OSCILLATOR STRENGTHS 

D1.00002: Testing quantum electrodynamics in the lowest singlet state of neutral beryllium9 Will Williams, Melody Cao, Emily Kaplan We present high precision spectroscopic results on the 2s2p J$=$1 singlet state in neutral beryllium9. Combined with theoretical predictions this measurement serves as a test of quantum electrodynamics and various theoretical methods for predicting the energy of this state. Our experimental setup consists of an oven at 1200C that produces a beam of beryllium atoms. The singlet state is probed transverse to the atomic beam with 235nm light from a frequency quadrupled titanium sapphire laser, where the frequency doubled light at 470nm is stabilized to an ultra low expansion cavity. We also present our progress on spectroscopy on the lowest triplet states and the ionization threshold. [Preview Abstract] 

D1.00003: Controlling autoionization in strontium twoelectronexcited states Robert Fields, Xinyue Zhang, F.Barry Dunning, Shuhei Yoshida, Joachim Burgd\"orfer One challenge in engineering longlived twoelectronexcited states, i.e., socalled planetary atoms, is autoionization. Autoionization, however, can be suppressed if the outermost electron is placed in a high$n$, $n\sim300600$, high$L$ state because such states have only a very small overlap with the inner electron, even when this is also excited to a state of relatively high $n$ and hence of relatively long lifetime. Here the $L$dependence of the autoionization rate for high$n$ strontium Rydberg atoms is examined during excitation of the core ion $5s$ $^2S_{1/2}$$5p$ $^2P_{3/2}$ transition. Measurements in which the angular momentum of the Rydberg electron is controlled using a pulsed electric field show that the autoionization rate decreases rapidly with increasing $L$ and becomes very small for values larger than $\sim20$. The data are analyzed with the aid of calculations undertaken using complex scaling. [Preview Abstract] 

D1.00004: Vibrational State Resolved Lifetimes of the Na$_{\mathrm{2}}$ 2$^{\mathrm{1}}\Sigma_{\mathrm{u}}^{\mathrm{+~}}$Double WellState. Lutz Huwel, Roy Anunciado, Nadeepa Jayasundara, Seth Ashman Lifetimes of individual Na$_{\mathrm{2}}$ rovibrational levels of the 2$^{\mathrm{1}}\Sigma_{\mathrm{u}}^{\mathrm{+}}$ double wellstate have been measured using a delayed photoionization technique. Ground state Na$_{\mathrm{2}}$ produced in a molecular beam is excited resonantly by the doubled output of a pulsed dye laser in the range 333  357 nm and then ionized by a 532 nm photon from a timedelayed Nd:YAG laser. By appropriate excitation laser tuning and systematic variation of the probe laser delay, rovibrational level resolved lifetimes are obtained for v$=$2549. The double well state lifetime values are found to decrease from about 50 ns at v$=$25 to about 40 ns near the barrier at around v$=$33 and then to increase back to about 50 ns at the highest observed level of v$=$ 49. We have also performed lifetime calculations using the Leve8 and Bcont programs by Leroy$^{\mathrm{1}}$, the latter in a version modified by Brett McGeehan. We find that including only boundbound transitions, the theoretical lifetime values are too large by a factor of up to 2. Inclusion of pertinent boundfree transitions improves the agreement noticeably. $^{\mathrm{1\thinspace }}$R. J. Le Roy, LEVEL 8.0: \textit{A Computer Program for Solving the Radial Schr\"{o}dinger Equation for Bound and Quasibound Levels}, University of Waterloo Chemical Physics Research Report CP663 (2007); see \underline {http://leroy.uwaterloo.ca/programs/}.. [Preview Abstract] 

D1.00005: Monochromatic Xray propagation in multiZ media for imaging and diagnostics including K$_{\alpha}$ Resonance Fluorescence Maximillian Westphal, Sara Lim, Sultana Nahar, Anil Pradhan Aimed at monochromatic Xray imaging and therapy [1], broadband, monochromatic, and quasimonochromatic Xray sources and propagation through low and highZ (HZ) media were studied with numerically and experimentally. Monte Carlo simulations were performed using the software package Geant4, and a new code Photx, to simulate Xray image contrast, depth of penetration, and total attenuation. The data show that monochromatic and quasimonochromatic Xrays achieve improved contrast at lower absorbed radiation doses compared to conventional broadband 120 kV or CT scans. Experimental quasimonochromatic highintensity laserproduced plasma sources and monochromatic synchrotron beam data are compared. Physical processes responsible for Xray photoexcitation and absorption are numerically modelled, including a novel mechanism for accelerating K$_{\alpha}$ resonance fluorescence via twin monochromatic Xray beam [2]. Potential applications are medical diagnostics and highZ material detection.\\ 1. S.N.Lim, et al, JRR 56, 77 (2015)\\ 2. S.N.Nahar, A.K. Pradhan, JQSRT 155, 32 (2015)\\ Acknowledgement: Ohio Supercomputer Center, Columbus, OH [Preview Abstract] 

D1.00006: LMO dielectronic resonances in highly charged bismuth Joseph Smiga, John Gillaspy, Yuri Podpaly, Yuri Ralchenko Dielectronic resonances from highZ elements are important for the analysis of high temperature plasmas. Thus, the extreme ultraviolet spectra of highly charged bismuth were measured using the NIST electron beam ion trap (EBIT) at beam energies ranging from 8.7~keV to 9.2~keV. The measured intensity ratios between forbidden magneticdipole lines in Bi$^{64+}$ and Bi$^{63+}$ show strong resonance features. The experimental data were compared to theoretical predictions from a largescale collisionalradiative model with the code NOMAD, and good agreement was found that allowed the identification of observed resonance features as the LMO innershell dielectronic resonances. It is common practice in EBIT experiments that ions are periodically dumped from the trap and replaced. However, in this particular experiment, the contents of the trap were not dumped for the duration of each 10~minute sampling. The effects of trap stability were studied and a small but noticeable shift in beam energy over time was observed. Potential explanations for this are considered. [Preview Abstract] 

D1.00007: Analytical calculation of susceptibility for Dopplerbroadened twolevel atoms in pumpprobe spectroscopy Seung Chul Yang, HyunJong Kang, HeungRyoul Noh An analytical study of susceptibility in pumpprobe laser spectroscopy for an atomic medium composed of twolevel atoms in the Doppler limit is presented. We derive an accurate analytical formula for susceptibility up to the first order at the Rabi frequency of the probe beam while the intensity of the pump beam is arbitrary. The analytical form of the susceptibility is expressed in a succinct single term rather than as a complicated summation, as presented in previous papers. We also derive analytical solutions for the linewidth and peak value of the absorption spectrum of the probe beam. [Preview Abstract] 

D1.00008: New Generation of Los Alamos Opacity Tables James Colgan, D. P. Kilcrease, N. H. Magee, M. E. Sherrill, J. Abdallah, P. Hakel, C. J. Fontes, J. A. Guzik, K. A. Mussack We present a new generation of Los Alamos OPLIB opacity tables$^1$ that have been computed using the ATOMIC code$^2$. Our tables have been calculated for all 30 elements from hydrogen through zinc and are publicly available through our website$^3$. In this poster we discuss the details of the calculations that underpin the new opacity tables. We also show several recent applications of the use of our opacity tables to solar modeling and other astrophysical applications. In particular, we demonstrate that use of the new opacities improves the agreement between solar models and helioseismology, but does not fully resolve the longstanding `solar abundance' problem. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DEAC5206NA25396. $^1$ J. Colgan et al, Astrophysical Journal, in press (2016). $^2$ N. H. Magee et al, {14th Topical Conference on Atomic Processes in Plasmas}, Eds: J. S. Cohen, S. Mazevet, and D. P. Kilcrease, (New York: AIP), pp~168; P. Hakel et al, J. Quant. Spectrosc. Rad. Transfer {\bf 99}, 265 (2006). [Preview Abstract] 

D1.00009: White Light PumpProbe Photothermal Mirror Spectrophotometer May Hlaing, Aristides Marcano We develop a new kind of spectrophotometer based on the photothermal mirror effect. The absorption of a focused tunable pump light by first atomic layers of the sample's surface generates a nanometric surface distortion or bump of thermal origin. A probe beam of light of fixed wavelength and with spot dimensions much larger than the pump beam's spot is used to test this thermal distortion. Changes in the wavefront of the reflected probe beam yields changes of the diffraction pattern of the reflected beam at the far field which can be used to produce a signal proportional to the amount of released heat. Tuning of the wavelength of the pump field generates a photothermal mirror spectrum. As tunable pump source we use the light from a Xenon arclamp filtered using a series of interference filter. This way we generate tunable pump light in the spectral region of 370730 nm with a HWHM of 5 nm and power density of the order of tens of microwatts per nanometer. We obtain photothermal mirror spectra of metallic surfaces and other nontransparent samples. We show that these spectra are fundamentally different from the usual reflectance spectra which measure the percentage of the total of the total energy reflected by the surface. [Preview Abstract] 

D1.00010: Polarization spectroscopy and laserlocking for excitation of ultracold potassium atoms Charles Conover, Max Eberhart, Philip Adamson We report on the use of polarization spectroscopy to lock the frequency of an externalcavity diode laser to a the 4s  4p$_{1/2}$ (770 nm), 4s  4p$_{3/2}$ (767 nm) and 4s  5p$_{1/2}$ and 4s  5p$_{3/2}$ (405 nm) transitions in potassium. A rate equation model is in good agreement with the observed lineshapes and the D2 transition lineshapes agree with prior experiments. We have used the dispersion shaped lines to lock the frequency of lasers for probing a magnetooptical trap's density on the D1 line and for stepwise excitation of potassium Rydberg states using the 4s  5p$_{3/2}$ transition. The technique has proven particularly helpful by enabling modulationfree locking of blue diode lasers. [Preview Abstract] 

D1.00011: An observation of a series of single and multi photon molecular transitions Jeonghun Lee, Tom Gallagher Microwave transitions between pair states composed of two Rb Rydberg atoms in a magnetooptical trap are investigated. This is an extension of the experiment that investigated the transition from ndnd to (n+1)d(n2)f state. The aforementioned transition is allowed because (n+2)p(n2)f state that is energetically close to ndnd state gets admixed into ndnd state as a result of the dipoledipole induced configuration interaction. The microwave transition is from the (n+2)p(n2)f part of the wavefunction to the (n+1)d(n2)f state. In the transition, the microwave drives a transition from (n+2)p to another state in one atom with the other atom remaining a spectator in the (n2)f state. A series of one, two, and three photon molecular transitions that occur due to the same mechanism was observed. Those are transitions from ndnd to (n+3)s(n2)f, (n+3)p(n2)f, nf(n2)f, and (n+4)s(n2)f. In addition, molecular transitions during which the microwave drives a transition from (n2)f to another state in one atom with the other atom remaining a spectator in the (n+2)p state were also observed. The molecular transitions of this type that were observed are ndnd to (n+2)p(n1)d and (n+2)p(n1)f. The measured transition frequencies were found to agree well with the calculated values. [Preview Abstract] 

D1.00012: Electronic Transition Dipole Moment and Radiative Lifetime Calculations of Lithium Dimer IonPair States Aydin Sanli, David Beecher, Marjatta Lyyra, Sylvie Magnier, Ergin Ahmed Lithium dimer molecular electronic states exhibit double wells and shoulders due to the interaction with the Li$^{\mathrm{+}} \quad +$ Li$^{\mathrm{}}$ ionpair configuration. The double well behavior is predominantly observed for higher lying electronic states of $^{\mathrm{1}}\Sigma _{\mathrm{g}}^{\mathrm{+}}$~symmetry at larger internuclear distance. The ionpair character of these potential energy curves makes their lifetimes also interesting because of the unusual behavior of their transition dipole moments which exhibit rapid changes around potential curve shoulders and double wells. In this work we present a computational study of lifetimes and transition dipole moment matrix elements for the lithium dimer ionpair states. We report here the \textit{ab initio} calculated electronic transition dipole moments between the n$^{1}\Sigma_{g}^{+} $ states and the A$^{1}\Sigma _{u}^{+} $~state, that vary strongly as a function of internuclear distance. In addition, we have calculated the radiative lifetimes,~$\tau $, of these ionpair states and compare them with experimental results from literature when available. [Preview Abstract] 

D1.00013: Precision Excited State Lifetime Measurements for Atomic Parity Violation and Atomic Clocks Jerry Sell, Brian Patterson, Alina Gearba, Jeremy Snell, Randy Knize Measurements of excited state atomic lifetimes provide a valuable test of atomic theory, allowing comparisons between experimental and theoretical transition dipole matrix elements. Such tests are important in Rb and Cs, where atomic parity violating experiments have been performed or proposed, and where atomic structure calculations are required to properly interpret the parity violating effect. In optical lattice clocks, precision lifetime measurements can aid in reducing the uncertainty of frequency shifts due to the surrounding blackbody radiation field. We will present our technique for precisely measuring excited state lifetimes which employs modelocked ultrafast lasers interacting with two counterpropagating atomic beams. This method allows the timing in the experiment to be based on the inherent timing stability of modelocked lasers, while counterpropagating atomic beams provides cancellation of systematic errors due to atomic motion to first order. Our current progress measuring Rb excited state lifetimes will be presented along with future planned measurements in Yb. [Preview Abstract] 

D1.00014: Contribution of the 1s2l3l' Dielectronic Recombination in LiLike Ar to the Hypothesized Dark Matter Related Faint Feature in Galaxy Clusters Amy Gall, Roshani Silwal, Joan Dreiling, Marco Ajello, John Gillaspy, Ethan Kilgore, Yuri Ralchenko, Endre Takacs Driven by the recent detection of an unidentified emission line previously reported at 3.553.57 keV in a stacked spectrum of galaxy clusters, we investigate the resonant DR process in Lilike Ar as a possible source of or contributor to the emission line. We are particularly interested in the Lilike transition 1s$^{\mathrm{2}}$2l1s2l3l', which produces a 3.62 keV photon near the unidentified line at 3.57 keV. The Electron Beam Ion Trap at NIST was used to produce and trap the highlycharged ions of argon. The energy of the quasimonoenergetic electron beam, set to a current of 60 mA, was incremented in steps of 15 eV to scan over all of the Lilike Ar DR resonances, including the resonance peak of interest. A solidstate germanium detector was used to take xray measurements perpendicular to the trap region. The DR cross section was measured and normalized to the wellknown photoionization cross sections using radiative recombination peaks in the measured spectra. Our measurements are compared to the AtomDB emission lines used to fit the spectra containing the unidentified line, and conclusions are presented. [Preview Abstract] 

D1.00015: Study of Labinding energies by analysis of its photodetachment spectrum Lin Pan, Donald Beck In this study, relativistic configuration interaction (RCI) is employed to investigate the electron affinity and binding energies of the negative ion of lanthanum, by reinterpreting an earlier experimental photoelectron kinetic energy spectrum [1] of La$^$. For the electron affinity of lanthanum, our study revises the original experimental interpretation of 0.47 $\pm$ 0.02 eV and agrees well with the earlier RCI value of 0.545 eV [2]. The calculation yields also the binding energies for thirteen excited states of La$^$. These energies are compared to results of recent experimental studies on La$^$ [35]. The details of the calculation, identities of main features in the experimental spectrum will be presented in our poster. [1] A. M. Covington {\it et al.}, {\em J. Phys. B} {\bf 31}, L855 (1998). [2] S. M. O'Malley and D. R. Beck, {\em Phys. Rev. A.} {\bf 79}, 012511 (2009). [3] C. W. Walter {\it et al.}, {\em Phys. Rev. Lett.} {\bf 113}, 063001 (2014). [4] E. Jordan {\it et al.}, {\em Phys. Rev. Lett.} {\bf 115}, 113001 (2015). [5] A. Kellerbauer {\it et al.}, {\em Phys. Scrip.} {\bf 90}, 054014 (2015). [Preview Abstract] 

D1.00016: Electron Impact Collision Strength in Si IX Hala noman, Y Gokce, Sultana Nahar, Anil Pradhan Results from work in progress under Iron Project on the electron impact excitation collision strengths and rate coefficients for transitions between the finestructure levels of the $2s^22p^2$, $2s2p^3$, $2p^4$, $2s^22p3s$, $2s^22p3p$, and $2s^22p3d$ configurations in Si IX will be presented. The fine structure collision strength has been calculated at very fine energy mesh using relativistic effects in BreitPauli Rmatrix method. Maxwellian averaged collision strengths have been tabulated for all possible transitions among all 46 enrgy levels. We made comparisions of our results with the previously reported results in the literature and found significant differences in low the temperature range(Te $<$ $10^6$ K) for few of the transitions. The correction to the previous reported values results due to more extensive expansion for Si IX target states. [Preview Abstract] 

D1.00017: ATOMATOM AND ATOMMOLLECULE COLLISIONS 

D1.00018: Towards inclusion of excited vibrational states in ultracold moleculemolecule quantum scattering calculations Christopher Ticknor, Brian Kendrick We report progress towards including excited vibrational states in quantum scattering calculations of NaKNaK at ultracold temperatures. We systematically use all pair potentials to build a complete 4 body potential energy surface. We study this 4body potential and the asymptotic rovibrational 2body basis. This allows for a more complete interaction as two molecules approach each other. We study where and how vibrationally excited states influence the asymptotic 2body rovibrational scattering potentials. This work is an intermediate step in performing the complete scattering calculations as we develop tools to bring together the long range, ultracold 2body scattering problem and the short range 4body quantum chemistry problem. [Preview Abstract] 

D1.00019: The Effects of Hybrid Optical Pumping on the Electron Spin Filter. Mark Rosenberry, Timothy Gay Under the low pressure conditions of our spin filter experiment, optically pumping a single alkali species runs into the problem of radiation trapping. To polarize a significant electron current requires a moderate alkali density, but in the absence of quenching effects such a vapor is limited to modest polarization, and hence the resulting electron polarization is also low. One possible solution is to introduce a second alkali species, which can be polarized by spin exchange with the laser polarized species. Since this second species does not interact with the laser, it does not suffer from radiation trapping, even if it has a substantial density. We report progress in experimental and computational studies of potassium/rubidium hybrid pumping in this regime [Preview Abstract] 

D1.00020: Theoretical study of resonances in lowenergy collisions of three identical atoms Chi Hong Yuen, VIatcheslav Kokoouline Resonances in lowenergy collisions of three identical atoms are studied theoretically using hyperspherical coordinates [1]. Two different methods are used and compared to determine positions and widths of threebody resonances: the complex absorbing potential [2] and eigenchannel Rmatrix [3] approaches. Good agreement between the results of the two approaches is found. Cross sections for dimer formation in threebody recombination is determined. For this purpose the formula of Ref. [4] is used (and rederived). The developed code is applied to study collisions of three hydrogen atoms at low energies. [1] B.R. Johnson, J. Chem. Phys. 73, 10 (1980) [2] J.Blandon, V.Kokoouline, F.MasnouSeeuws, Phys. Rev. Lett. 75, 042508 (2007) [3] M.Aymar, C.H.Greene, E.LucKoenig, Rev. Mod. Phys. 68, 1015 (1996) [4] N.P.Mehta, S.T.Rittenhouse, J.P.D'Incao, J.von Stecher, C.H.Greene, Phys. Rev. Lett. 103, 153201 (2009) [Preview Abstract] 

D1.00021: Formation of SiO by radiative association: the impact of resonances Robert C. Forrey, Brendan M. McLaughlin, James F. Babb, Phillip C. Stancil Detailed quantum chemistry calculations within the MRCI+Q approximation are presented using an augccpV6Z (AV6Z) basis set, for the potential energy curves and transition dipole moments between low lying molecular states of singlet spin symmetry for the SiO molecule. The high quality molecular data are used to obtain radiative association cross sections and rate coefficients for collisions between ground state Si and O atoms. Quantal methods are used and compared with semiclassical results. We find that the resonance features present in the quantum mechanical cross sections play a significant role, enhancing the rate coefficients at low temperatures by several orders of magnitude. These new molecular formation rates will therefore have important implications for applications in astrophysics. [Preview Abstract] 

D1.00022: Rovibrationally Inelastic AtomMolecule Collision Cross Sections from a Hard Sphere Model Jacob Lashner, Brian Stewart Hardshell models have long been used to elucidate the principal features of molecular energy transfer and exchange reaction in the A + BC system. Nevertheless, no threedimensional hardshell calculation of inelastic collision cross sections has been reported. This work aims to fill that void. A particular motivation comes from our experimental results, which show the importance of equatorial impacts in the vibrational excitation process. \\ Working with the simple hardsphere model, we incorporated secondary impacts, defined as those in which A strikes C after striking B. Such collisions are important in systems such as Li$_2$  X, in which vibrational energy transfer occurs principally through side impacts. We discuss the complexity this adds to the model and present fully threedimensional cross sections for rovibrational excitation of an initially stationary molecule in the homonuclear A + B$_2$ system, examining the cross section as a function of the masses and radii of the atoms. We show how the features in the cross section evolve as these parameters are varied and calculate the contribution of secondary (nearequatorial) impacts to the dynamics. We compare with recent measurements in our laboratory and with the results of quasiclassical trajectories. [Preview Abstract] 

D1.00023: Rotationally inelastic collisions of He and Ar with NaK: Theory and Experiment T. J. Price, A. C. Towne, K. Richter, J. Jones, A. P. Hickman, J. Huennekens, C. Faust, R. F. Malenda, A. J. Ross, P. Crozet, D. Talbi, R. C. Forrey Rotationally inelastic thermal collisions of NaK $A\,^1\Sigma^+$ molecules with He and Ar have been studied at Lehigh and Lyon. In both laboratories, a pump laser excites a particular rovibrational level $A\,^1\Sigma^+$($v, J$). Strong transitions from the pumped ($v, J$) level and weaker transitions from collisionallypopulated levels ($v,J^{\prime} = J + \Delta J$) occur. Ratios of line intensities yield information about population and orientation transfer. At Lyon, we also identify $v$ changing collisions. A strong propensity for $\Delta J =$ even transitions is observed for He and Ar. Theoretical calculations are underway; we've calculated HeNaK and ArNaK potential surfaces using GAMESS and performed coupled channel scattering calculations for $JM\rightarrow J^{\prime}M^{\prime}$ transitions. Semiclassical formulas for the cross sections have been obtained and agree well with our quantum mechanical calculations. Using the vector model, where $J$ precesses with polar angle $\theta$ about the $z$axis, we derived the distribution of final polar angles $\theta^{\prime}$ and final $M^{\prime}$ states. We identify a special case where the $\theta^{\prime}$ distribution is a Lorentzian centered at $\theta$. [Preview Abstract] 

D1.00024: Molecular Energy Transfer in Highly Excited Electronic States Jacob Fanthorpe, Brian Stewart We present an experimental study of the energytransfer dynamics of inert gases with lithium dimer in highly excited electronic states: \begin{eqnarray*} \mathrm{Li}_2 (3) \ \mathrm{or} \ (4) ^1 \Sigma_g^+ (v_i,j_i) + \ \mathrm{X} \ \rightarrow \mathrm{Li}_2 (3) \ \mathrm{or} \ (4) ^1 \Sigma_g^+ (v_f,j_f) + \mathrm{X}, \end{eqnarray*} with the lithium molecule prepared via twophoton excitation in a single rovibrational level in the E $(3) ^1 \Sigma_g^+$ or F $(4) ^1 \Sigma_g^+$ excited electronic states. The E state resembles the previously studied A $(1) ^1 \Sigma_u^+$ state in having nearly the same $r_e$ and $\omega_e$ values, indicating that differences in the rate constants are most likely due to difference in the spatial distributions of the electrons. We find that, in both the E and F states, rotational energy transfer occurs at a similar overall rate as in the previously studied A state. However, the distribution of final levels is dramatically different from that in the A state, being much narrower. This implies a more nearly isotropic interaction in the highly excited states. The rotational distribution of vibrationally inelastic rate constants in the F state, on the other hand, resembles that in the A state. [Preview Abstract] 

D1.00025: Reactive scattering of O and H$_2$ and quenching of OH at collision energies up to 4.4 eV Marko Gacesa, Vasili Kharchenko We report new cross sections for the O($^3$P) + H$_2$ reactive scattering as well as quenching rates for rotationally and vibrationally excited OH by H atoms for a range of collision energies from 0.4 and 4.4 eV. These processes are important for understanding nonlocal thermal equilibrium (nonLTE) regime in astrophysical environment such as photondominated regions (PDRs) and evolution of planetary atmospheres in time, including the atmospheres of Earth and Mars. The cross sections were calculated quantum mechanically using coupledchannel formalism implemented in MOLSCAT and ABC computer codes on refitted recent potential energy surfaces for $^3$A$'$ and $^3$A$''$, while the surfacehopping effects were estimated from models and similar atommolecule reactions. A large basis set was used to ensure the convergence at higher energies. Our results agree well with the published data at lower energies and indicate that reduceddimensionality approach at collision energies higher than about 1.5 eV may not be adequate. Differential cross sections and diffusion cross sections, of interest in transport calculations, are also reported. [Preview Abstract] 

D1.00026: ATOMIC, MOLECULAR AND CHARGED PARTICLE COLLISIONS 

D1.00027: Simple analytic expressions for correcting the factorizable formula for Compton } \textbf{scattering doubly differential cross sections within impulse approximation L. A. LaJohn, R. H. Pratt The factorizable form of the relativistic impulse approximation (RIA) expression for Compton scattering doubly differential cross sections (DDCS) becomes progressively less accurate as the binding energy of the ejected electron increases. This expression, which we call the RKJ approximation, makes it possible to obtain the Compton profile (CP) from measured DDCS. We have derived three simple analytic expressions, each which can be used to correct the RKJ error for the atomic Kshell CP obtained from DDCS for any atomic number Z. The expression which is the most general is valid over a broad range of energy $\omega $ and scattering angle $\theta $, a second expression which is somewhat simpler is valid at very high $\omega $ but over most $\theta $, and the third which is the simplest is valid at small $\theta $ over a broad range of $\omega $. We demonstrate that such expressions can yield a CP accurate to within a 1{\%} error over 99{\%} of the electron momentum distribution range of the Uranium Kshell CP. Since the Kshell contribution dominates the extremes of the whole atom CP (this is where the error of RKJ can exceed an order of magnitude), this region can be of concern in assessing the bonding properties of molecules as well as semiconducting materials. [Preview Abstract] 

D1.00028: Review of the progress in model theoretical studies of $e + A@{\rm C}_{60}$ electron scattering V. Dolmatov, M. Amusia, L. Chernysheva A series of recent semiempirical theoretical studies of electron scattering off endohedral atoms $A$@C$_{60}$ [14] have identified interesting measurements as well as more rigorous calculations of $e + A@{\rm C}_{60}$ scattering to perform. This report provides the interested researchers with a review of the most significant findings of works [14] on $e + A@{\rm C}_{60}$ scattering. First, we demonstrate features of $e + A@{\rm C}_{60}$ elastic scattering of slow electrons [1, 2] and lowfrequency bremsstrahlung [1] when both the atom $A$ and the cage C$_{60}$ are ``frozen'' [1, 2]. Then [3], we ``unfrozen'' the atom $A$ but keep the C$_{60}$ cage ``frozen'' and demonstrate novel effects of dynamical polarization of the atom $A$ under the ``frozen'' C$_{60}$ confinement on $e + A@{\rm C}_{60}$ scattering. Finally, we demonstrate the combined effect of both the dynamical polarization of the encapsulated atom and the static polarization of C$_{60}$ on the scattering process [4].\\ $[1]$ V. K. Dolmatov et.al., PRA \textbf{91}, 062703, 2015. $[2]$ M. Ya. Amusia and L. V. Chernysheva, JETP Lett. \textbf{100}, 503 (2015). $[3]$ V. K. Dolmatov, M. Ya. Amusia, and L. V. Chernysheva, PRA \textbf{92}, 042709 (2015). $[4]$ M. Ya. Amusia and L. V. Chernysheva, arXiv:1512.00211, 2015. [Preview Abstract] 

D1.00029: Analysis of xray emission in chargeexchange collisions of C$^{6+}$ ions with He and H$_{2}$ Anthony C.K. Leung, T. Kirchner Charge exchange in C$^{6+}$He and H$_{2}$ collisions followed by xray emission is examined using the twocenter basis generator method within the independent electron model. The analysis examines the two collision systems for low to intermediate projectile energies. We perform capture cross section and radiative cascade calculations to obtain Lyman line emission ratios which can be compared to measurements that were carried out at the Oak Ridge National Laboratory Multicharged Ion Research Facility [1,2]. Singleelectron capture is considered for the C$^{6+}$He system while both single and autoionizing double capture are considered for the C$^{6+}$H$_{2}$ system. We also examine the effects of a timedependent screening potential that models target response on the $l$ distribution of the capture cross sections and the emission ratios. Calculated line emission ratios based on the noresponse approximation are found to be in satisfactory agreement with the measurements. [1] X. Defay et al., Phys. Rev. A 88, 052702 (2013); [2] M. Fogle et al., Phys. Rev. A 89, 042705 (2014). [Preview Abstract] 

D1.00030: Diode Laser Absorption Spectroscopy of Lithium Atomic Beams Paul Oxley, Joseph Wihbey We present final results of a method to determine the density of an atomic beam, building on previous work [1]. Advances described in the present work include use of a double laser beam technique, implementing more accurate laser frequency calibration, and providing an independent confirmation of our experimental results. Analysis of the accuracy and precision of our measurements is also provided. With these improvements we are able to measure atomic beam fractional absorptions as low as 10$^{\mathrm{5}}$ on a minute timescale. Stronger absorptions of 10$^{\mathrm{3}}$ or larger, which are more typically found in AMO experiments, can be measured to a precision of 3{\%} on a one second timescale. Knowledge of atomic beam density is important to quantify the results of atom collision experiments which use an atomic beam target. [1] http://meetings.aps.org/link/BAPS.2015.DAMOP.K1.169 [Preview Abstract] 

D1.00031: Ionbiomolecule collisions studied within the independent atom model including geometric screening corrections H.J. L\"udde, A. Achenbach, T. Kalkbrenner, H.C. Jankowiak, T. Kirchner A recently introduced model to account for geometric screening corrections in an independentatommodel description of ionmolecule collisions [1] is applied to proton collisions from amino acids and DNA and RNA nucleobases. The correction coefficients are obtained from using a pixel counting method (PCM) for the exact calculation of the effective cross sectional area that emerges when the molecular cross section is pictured as a structure of (overlapping) atomic cross sections. This structure varies with the relative orientation of the molecule with respect to the projectile beam direction and, accordingly, orientationindependent total cross sections are obtained from averaging the pixel count over many orientations. We present net capture and net ionization cross sections over wide ranges of impact energy and analyze the strength of the screening effect by comparing the PCM results with Bragg additivity rule cross sections and with experimental data where available. [1] H.J. L\"udde et al, J. Phys. Conf. Ser. 635, 032076 (2015) [Preview Abstract] 

D1.00032: A CF$_{4}$ based positron trap Srdjan Marjanovic, Ana Bankovic, Sasa Dujko, Adam Deller, Ben Cooper, David Cassidy, Zoran Petrovic All positron buffer gas traps in use rely on N$_{2}$ as the primary trapping gas due to its conveniently placed a$^{1}\Pi $ electronic excitation cross section that is large enough to compete with positronium (Ps) formation in the threshold region. Its energy loss of 8.5 eV is sufficient to capture positrons into a potential well upon a single collision. The competing Ps formation, however, limits the efficiency of the two stage trap to 25 {\%}. As positron moderators produce beams with energies of several eV we have proposed to use CF$_{4}$ in the first stage of the trap, due to its large vibrational excitation cross section, where several vibrational excitations would be sufficient to trap the positrons with small losses. Apart from the simulations we also report the results of attempts to apply this approach to an existing Surkotype positron trap. Operating the unmodified trap as a CF$_{4}$ based device proved to be unsuccessful, due primarily to excessive scattering due to high CF$_{4}$ pressure in the first stage. However, the performance was consistent with subsequent simulations using the real system parameters. This agreement indicates that an efficient CF$_{4}$ based scheme may be realized in an appropriately designed trap. [Preview Abstract] 

D1.00033: Towards the full quantum description of lowenergy reactive collisions of O$^{\mathrm{}}$ with H$_{\mathrm{2}}$ Karel Houfek, Martin Cizek In this contribution we present preliminary results for reactive collisions of O$^{\mathrm{}}$ anions with hydrogen molecules at low energies. The three lowest potential energy surfaces for the anion are calculated for large number of geometries where the electron is bound. The conical intersections of these three states are located together with the intersections with the potential energy surface of the neutral molecule. In the autodetachment region where electron can escape leaving the neutral molecule behind we performed the fixednuclei electron scattering calculations using the UK Rmatrix codes to obtain input data for construction of the nonlocal resonance model for full quantum description of nuclear dynamics. Classical trajectory calculations of the dynamics are also presented. [Preview Abstract] 

D1.00034: Cross sections for Scattering and Mobility of OH$^{\mathrm{}}$ and H$_{\mathrm{3}}$O$^{\mathrm{+}}$ ions in H$_{\mathrm{2}}$O Zoran Petrovic, Vladimir Stojanovic, Dragana Maric, Jasmina Jovanovic Modelling of plasmas in liquids and in biological and medical applications requires data for scattering of all charged and energetic particles in water vapour. We present swarm parameters for OH$^{\mathrm{}}$ and H$_{\mathrm{3}}$O$^{\mathrm{+}}$, as representatives of principal negative and positive ions at low pressures in an attempt to provide the data that are not yet available. We applied DenpohNanbu procedure to calculate cross section sets for collisions of OH$^{\mathrm{}}$ and H$_{\mathrm{3}}$O$^{\mathrm{+}}$ ions with H$_{\mathrm{2}}$O molecule. Swarm parameters for OH$^{\mathrm{}}$ and H$_{\mathrm{3}}$O$^{\mathrm{+}}$ ions in H$_{\mathrm{2}}$O are calculated by using a well tested Monte Carlo code for a range of $E/N(E$electric field, $N$gas density) at temperature $T=$295~K, in the low pressure limit. Nonconservative processes were shown to strongly influence the transport properties even for OH$^{\mathrm{}}$ ions above the average energy of 0.2~eV($E/N$\textgreater 200~Td). The data are valid for low pressure water vapour or small amounts in mixtures. They will provide a basis for calculating properties of ionwater molecule clusters that are most commonly found at higher pressures and for modelling of discharges in liquids. [Preview Abstract] 

D1.00035: QuantumStateResolved IonMolecule Chemistry Gary Chen, Tiangang Yang, Wesley Campbell, Eric Hudson We propose a method to achieve quantumstateresolved ionmolecule chemistry by utilizing cryogenic buffer gas cooling techniques and a combination of ion imaging and mass spectrometry of targets in an RF Paul trap. Cold molecular species produced by a cryogenic buffer gas beam (CBGB) are introduced to target ion species in an linear quadrupole trap (LQT) where ion imaging techniques and time of flight mass spectrometry (ToF) are then used to observe the target ions and the charged reaction products.[1][2] By taking advantage of the large ionneutral interaction cross sections and characteristically long ion trap lifetimes, we can utilize the precision control over quantum states allowed by an ion trap to resolve statetostate quantum chemical reactions without highdensity molecular sample production, well within proposed capabilities. The combination of these two very general cold species production techniques allows for production and observation of a broad range of ionneutral reactions. We initially plan to study chemical reactions between sympathetically cooled carbon ions (via laser cooled beryllium ions) with buffer gas cooled water. This work is supported by the US Air Force Office of Scientific Research. [Preview Abstract] 

D1.00036: IONATOM AND IONION COLLISIONS 

D1.00037: Electron transfer, ionization, and excitation in collisions between protons and the ions N$^{6+}$ and O$^{7+}$ Thomas Winter Coupledstate cross sections are being determined for electron transfer, ionization, and excitation in collisions between keVenergy protons and the hydrogenic ions N$^{6+}$ and O$^{7+}$, extending early\footnote{T. G. Winter, Phys. Rev. A {\bf 35}, 3799 (1987).} and more recent work\footnote{T. G. Winter, Phys. Rev. A {\bf 87}, 032704 (2013).} on the less highly charged target ions He$^{+}$, Li$^{2+}$, Be$^{3+}$, B$^{4+}$, and C$^{5+}$. As in the more recent work, a basis of 60 Sturmians on each center is being used, and in a second calculation, a basis of 280 Sturmians on the target nucleus and a single $1s$ function on the proton is being used. The extent to which highenergy scaling rules with target nuclear charge $Z$ are valid is being examined further for transfer to the ground state, total transfer, and ionization, as well as for excitation and individualstate processes at intermediate energies near where the cross sections peak. [Preview Abstract] 

D1.00038: Excitationionization processes in Kshell vacancy production in Li by fast bare oxygen ions: doublydifferential cross sections M.D. \'Spiewanowski, L. Guly\'as, M. Horbatsch, T. Kirchner Recent theoretical work has demonstrated that $K$shell vacancy production in Li by 1.5 MeV/amu O$^{8+}$ impact cannot be understood as a simple oneelectron process. Rather, a certain twoelectron excitationionization process, in which the valence electron is removed, while one of the $K$shell electrons makes a transition to an excited state, was found to give the dominant contribution to the singlydifferential cross section at low to intermediate energies of the outgoing electron [1]. In this work, we extend the calculations to the doublydifferential level and present cross sections which are differential in the electron energy and the transverse momentum transfer [2]. The calculation involves the combination of impactparameterdependent singleelectron amplitudes and a twodimensional Fourier transformation of the resulting multielectron amplitudes to obtain momentumtransferdependent transition matrix elements. Results are found to be in good agreement with recent measurements, especially at low outgoing electron energy, and underline the importance of twoelectron excitation ionization in this collision system. [1] T. Kirchner et al., Phys. Rev. A 89, 062702 (2014); [2] M. D. \'Spiewanowski et al., Phys. Rev. A 93, 012707 (2016) [Preview Abstract] 

D1.00039: Progress towards Generating Rydberg State, One Electron Ions Joan Dreiling, Shannon Fogwell Hoogerheide, Aung Naing, Joseph Tan We report on progress towards producing hydrogenlike ions in Rydberg states from bare nuclei. Fully stripped neon atoms (Ne$^{\mathrm{10+}})$ are produced by the electron beam ion trap (EBIT) at NIST. These ions are extracted via a beamline from the EBIT into a second apparatus where they are captured at low energy in a unitary Penning trap [1]. The second apparatus has a crossbeam configuration, with a perpendicular beam of laser excited Rb atoms intersecting the ion beam at the Penning trap. While stored in the trap, the ions can interact with the Rb and, through charge exchange interactions, the bare nuclei can capture one or more electrons from the Rb. The ions are then analyzed by dumping the trap to a timeofflight detector, which allows determination of the ion charge state evolution [1]. This work builds towards laser spectroscopy on hydrogenlike ions in circular Rydberg states to obtain a value for the Rydberg constant independent of nuclear size effects [2]. Such a measurement could shed some light on the proton radius puzzle [3]. [1] S.F. Hoogerheide \textit{et al.}, Atoms \textbf{3}, 367 (2015). [2] U.D. Jentschura \textit{et al.}, Phys. Rev. Lett. \textbf{100}, 160404 (2008). [3] R. Pohl \textit{et al.}, Annu. Rev. Nucl. Part. Sci. \textbf{63}, 175 (2013). [Preview Abstract] 

D1.00040: Radiative loss and charge exchange in low energy Na  Ca$^+$ collisions B. M. McLaughlin, K. McAlpine, J. F. McCann, R. Pattillo, P. C. Stancil, R. C. Forrey, J. F. Babb Experiments on radiative loss and capture are currently being performed at the University of Connecticut. In response to this experimental effort we have performed detailed calculations for a variety of loss and capture processes. Several low lying states of the NaCa$^+$ cation are used with the accurate potentials energy curves, transition dipole moments and nonadiabatic coupling matrix elements between the states, obtained at the MRCI+Q level of approximation with the MOLPRO suite of quantum chemistry codes. Cross sections and rate coefficients are calculated for radiative charge transfer (RCX), radiative association (RA) and charge exchange in a fully quantum molecular closecoupling (MOCC) approximation at the higher energies. We use a variety of approaches, the optical potential method, semiclassical and MOCC methods to compare and contrast approximations. In addition a kinetic theory recently applied to SiO [1] is utilized which illustrates the dramatic impact resonances have on the radiative association rates. \begin{enumerate} \item R.C. Forrey, J.F. Babb, P.C. Stancil and B.M. McLaughlin, J. Phys. B: At. Mol. Opt. Phys. {\it in press} (2016) \end{enumerate} [Preview Abstract] 

D1.00041: Doubleelectron capture by highlyionized atoms isolated at very low energy Shannon Fogwell Hoogerheide, Joan M. Dreiling, Arda Sahiner, Joseph N. Tan Charge exchange with background gases, also known as electron capture processes, is important in the study of comets [1], controlled fusion energy [2], antimatter atoms [3], and proposed oneelectron ions in Rydberg states. However, there are few experiments in the very low energy regime that could be useful for further theoretical development. At NIST, highlycharged ions extracted from an electronbeam ion trap can be isolated with energy $<$ 10 eV in a compact Penning trap. By controlling the background gas pressure and composition, the charge exchange rates can be studied. Fully stripped neon or other ions are held in the trap for varying lengths of time and allowed to interact with different background gases at multiple pressures. The ions are then pulsed to a timeofflight detector to count the population of each charge state. Analysis using a system of rate equations yields information about the ion cloud expansion and singleelectron capture rates. A substantial amount of doubleelectron capture is also observed. We present the relative rates and discuss the error budget.\\ \\[] [1] T. E. Cravens, Science 296, 1042 (2002)\\[] [2] R. C. Isler, Plasma Phys. Control. Fusion 36, 171208 (1994)\\[] [3] C. H. Storry, et. al., Phys. Rev. Lett. 93, 263401 (2004) [Preview Abstract] 

D1.00042: Electronic Structure Calculations of Highly Charged Ions Steve Bromley, Marcin Ziolkowski, Joan Marler Exotic systems like Highly Charged Ions (HCIs) are attracting more attention based on their properties and possible interactions. Abundance of HCIs in the solar wind and their interaction with the upper atmosphere puts them in the attention of astro and atmospheric physicists. Also, their unique properties originating in the high charge make them an excellent candidate for precision measurements and the next generation of atomic clocks. For a better understanding of the dynamics of processes involving HCIs a combined theoretical and experimental effort is needed to study their basic properties and interactions. Both theory and experiment need to be combined due to the extreme nature of these systems. We present preliminary insight into electronic structure of light HCIs, their interactions with neutral atoms and dynamics of charge transfer processes. [Preview Abstract] 

D1.00043: Charge Exchange with Highly Charged Ions Jeremy Glick, Kevin Ferri, Jaclyn Schmitt, Joshua Hanson, Joan Marler A detailed study of the physics of highly charged ions (HCIs) is critical for a deep understanding of observed phenomena resulting from interactions of HCIs with neutral atoms in astrophysical and fusion environments. Specifically the charge transfer rates and spectroscopy of the subsequent decay fluorescence are of great interest to these communities. Results from a laboratory based investigation of these rates will be presented. The experiment takes advantage of an energy and charge state selected beam of HCIs from the recently online Clemson University EBIT (CUEBIT). Progress towards an experimental apparatus for retrapping HCIs towards precision spectroscopy of HCIs will also be presented. [Preview Abstract] 

D1.00044: PHOTONIZATION, PHOTODETACHMENT AND PHOTODISSOCIATION TBD [Preview Abstract] 

D1.00045: Photodissociation of CS and SiO from Excited Rovibrational Levels P. C. Stancil, R. J. Pattillo, B. M. McLaughlin, J. F. McCann, R. C. Forrey, J. F. Babb Photodissociation due to ultraviolet (UV) photons is a dominant molecular destruction process in a variety of UVirradiated interstellar (IS) environments. While most astrochemical models adopt photodissociation rates computed from cross sections out of the molecule's ground rovibrational level ($v=0,J=0$), they also assume a standard local IS radiation field and opacity due to standard IS dust. However, none of these conditions are satisfied in a host of environments including photodissociation regions, protoplanetary disks, and outflows from AGB stars. To allow for the calculation of reliable photodissociation rates, we compute cross sections from all bound $v,J$ levels of the ground electronic state for two example molecules, CS and SiO. The cross sections are computed for a large number of excited electronic states using a twostate fully quantum perturbation approach. New ab initio potential energies and transition dipole moment functions, used in the photodissociation calculations, were obtained at the MRCI+Q level of theory using the quantum chemistry package MOLPRO. Applications of the $v,J$stateresolved cross sections will be presented as well as LTE photodissociation cross sections which assume a Boltzmann distribution of initial $v,J$ levels. [Preview Abstract] 

D1.00046: The Iron Project \& Iron Opacity Project: Updates on Photoionization, ElectronIon Recombination of Fe XVII and Ca XV W. Eissner, S. Nahar, A. Pradhan, H. Hala, L. Zhao, J. Bailey We have carried out converged close coupling (CCC) calculations for photoionization of Nelike Fe~XVII and demonstrate ordersofmagnitude enhancements in cross section due to successive core excitations. Convergence criteria are: (i) inclusion of sufficient number of residual ion Fe~XVIII core states and (ii) highresolution of myriad autoionizing resonances. We discuss verification of the conventional oscillator strength sumrule in limited energy regions for boundfree plasma opacity. We will also report preliminary results from a larger Rmatrix calculations of photoionization cross sections and electronion recombination rates of Ca~XV where Rydberg series of resonances are included for core excitations to 28 states of n=2,3 complexes in contrast to previous 7 states of n=2 complex. The new results show existence of highpeak resonances of n=3 complex and enhanced background in high energy photoionization and a corresponding enhancement in the recombination in the high temperature region.\\ * Partial support: NSF, DOE,Ohio Supercomputer Center [Preview Abstract] 

D1.00047: An Atomic Photoionization Experiment by Harmonic Generation Spectroscopy Carlos Trallero, Mikhail Frolov, Tatiana S. Sarantseva, Nikolay Manakov, Kristen D. Fulfer, Benjamin Wilson, Jan Tro\ss, Xiaoming Ren, Erwin Poliakoff, Alexander A Silaev, Nikolay Vvedenskii, Anthony Starace Measurements of the highorder harmonic generation yield of the argon (Ar) atom driven by a strong elliptically polarized laser field are shown to completely determine the fieldfree differential photoionization cross section of Ar, i.e., the energy dependence of both the angleintegrated photoionization cross section and the angular distribution asymmetry parameter. [Preview Abstract] 

D1.00048: Double Photoionization of Atomic Oxygen Madhushani Wickramarathna, Thomas Gorczyca, Connor Ballance, Wayne Stolte Double photoionization of atomic oxygen was first measured at Aladdin, a secondgeneration synchrotron source, at lower resolution (Angel and Samson, PRA, 38, 5573, 1988). Here we present new experimental and theoretical results for the direct double photoionization of atomic oxygen. The experiment was performed at the Advanced Light Source for photon energies near the doubleionization threshold, revealing rich resonance structures converging to multiple singleionization thresholds. Stateoftheart calculations were performed using the Rmatrix with pseudostates (RMPS) method (P. G. Burke, {\em Rmatrix Theory of Atomic Collisions}, Springer 2011) as implemented by Gorczya and Badnell (JPB, 30, 3897, 1997), and recently applied, in a converged representation, to the double photoionization of helium (T. W. Gorczyca et al., JPB, 46, 195201, 2013). The muchlarger calculation required for oxygen, due to the many target state symmetries compared to helium, necessitated a parallel RMPS approach. Comparison between theoretical and experimental results shows overall qualitative agreement but also some puzzling discrepancies: experimental features that are not reproduced by the RMPS calculations. [Preview Abstract] 

D1.00049: Virtual detector methods for efficiently computing momentumresolved dissociation and ionization spectra Alex Kramer, Uwe Thumm We discuss a class of windowtransformbased ``virtual detector'' methods for computing momentumresolved dissociation and ionization spectra by numerically analyzing the motion of nuclear or electronic quantummechanical wavepackets at the periphery of their numerical grids. While prior applications of such surfaceflux methods considered semiclassical limits to derive ionization [1] and dissociation [2] spectra, we systematically include quantummechanical corrections and extensions to higher dimensions, discussing numerical convergence properties and the computational efficiency of our method in comparison with alternative schemes for obtaining momentum distributions. Using the example of atomic ionization by co and counterrotating circularly polarized laser pulses [3], we scrutinize the efficiency of common finitedifference schemes for solving the timedependent Schr\"{o}dinger equation in virtual detection and standard Fouriertransformation methods for extracting momentum spectra. [1] B. Feuerstein and U. Thumm, J. Phys B \textbf{36}, 707 (2003). [2] M. Magrakvelidze, C. M. Aikens, and U. Thumm, Phys. Rev. A \textbf{86},023402 (2012). [3] D. B. Milosovic, et al., Phys. Rev. A \textbf{61},063403 (2000). [Preview Abstract] 

D1.00050: TIMERESOLVED ELECTRON DYNAMICS AND ATTOSECOND SPECTROSCOPY 

D1.00051: Characterization of induced nanoplasmonic fields in timeresolved photoemission from gold nanospheres: a classical trajectory approach Erfan Saydanzad, Uwe Thumm Attosecond timeresolved (XUVpump, IRprobe) spectroscopy has been shown to be a powerful method for investigating the electron dynamics in atoms, and this technique is now being transferred to the investigation of electronic excitations, electron propagation, and collective electronic (plasmonic) effects in solids [1,2]. Based on classical trajectory calculations, we simulated (i) the final photoelectron velocity distribution in order to provide observable velocitymap images for gold nanospheres of 10 and 100 nm diameter and (ii) streaked photoemission spectra. By analyzing our numerical results, we illustrate how spatiotemporal information about the subIRcycle plasmonic and electronic dynamics is encoded in velocitymap images and streaked photoelectron spectra. [1] ``Attosecond physics: attosecond streaking spectroscopy of atoms and solids'', U. Thumm, Q. Liao, E. M. Bothschafter, F. S\"{u}{\ss}mann, M. F. Kling, and R. Kienberger, p. 387, Handbook of Photonics, Vol. 1, (Wiley, 2015). [2] ``Attosecond timeresolved streaked photoemission from Mgcovered W(110) surfaces'', Q. Liao and U. Thumm, Phys. Rev. A 92, 031401(R) (2015). [Preview Abstract] 

D1.00052: Attosecond interferometry on surfaces: Laserassisted photoemission from Ag(111) and Au(111) by an XUV pulse train Marcelo J. Ambrosio, Uwe Thumm Motivated by recent RABBITT experiments [1], we numerically investigated electron emission from metal surfaces by a pulse train of phase coherent attosecond XUV pulses into the assisting electric field of a timedelayed IR laser pulse. From the delaydependent oscillations of the firstsidebandelectron yields in our simulated spectra we deduced the atomic phases of the pulse train's higher harmonic components. These calculations allow us to extract physical properties of solid surfaces, as we numerically demonstrate for the Ag(111) and Au(111) surfaces targeted in [1], including photoemission from conductionband and corelevel electrons [2]. [1] R. Locher, L. Castiglioni, M. Lucchini, M. Greif, L. Gallmann, J. Osterwalder, M. Hengsberger and U. Keller, Optica \textbf{2}, 405 (2015). [2] C. H. Zhang and U. Thumm, Phys. Rev. A \textbf{80}, 032902 (2009). [Preview Abstract] 

D1.00053: Subadditivity in Electron Emission from GaAs Evan Brunkow, Nathan Clayburn, Maria Becker, Eric Jones, Herman Batelaan, Timothy Gay When two spatiallyoverlapped laser pulses (775 nm center wavelength, 75 fs duration) are incident on an untreated \textless 100\textgreater GaAs crystal surface, the electron emission rate depends on the temporal separation between the two pulses [1]. We have shown that for delays between 0.2 and 1000ps, the emission rate is ``subadditive'', i.e., is lower than when the beams have separation \textgreater \textgreater 1 ns. We believe the cause of this subadditivity is an increase in reflectance and transmittance due to electrons occupying the excited state of the GaAs. We are now able to manipulate the magnitude of the subadditivity by changing the number of electrons that are in the excited state. Subadditivity is not observed with tungsten tip surfaces which have no excited state. [1] E. Brunkow \textit{et al.}, Bull. Am. Phys. Soc. \textbf{60} (2015) [Preview Abstract] 

D1.00054: Wigner time delay in photodetachment of negative ions s. Saha, P. C. Deshmukh, J. Jose, A. S. Kkeifets, S. T. Manson In recent years, there has been much interest in studies on Wigner time delay [1] in atomic photoionization using various experimental techniques and theoretical methodologies [2]. In the present work, we report time delay in the photodetachment of negative ions using the relativisticrandomphase approximation (RRPA), which includes relativistic and important correlation effects [3,4]. Time delay is obtained as energy derivative of phase of the photodetachment complex transition amplitude. We investigate the time delay in the dipole n$p\to \varepsilon d$ channels in the photodetachment of F$^{\mathrm{}}$ and Cl$^{\mathrm{}}$, and in n$f\to \varepsilon g $channels in the photodetachment of Tm$^{\mathrm{}}$. In photodetachment of the negative ions, the photoelectron escapes in the field of the neutral atom and thus does not experience the nuclear Coulomb field; hence the phase is devoid of the Coulomb component. The systems chosen are well suited to examine the sensitivity of the photodetachment time delay to the centrifugal potential [5]. The ions chosen have closed shells, and thus amenable to the RPA. Work supported by DOE, Office of Chemical Sciences, DST (India), and the Australian Research Council. [1] E. P. Wigner Phys. Rev. \textbf{98} 145(1955); [2] R. Pazourek, S. Nagele and J. Burgd\"{o}rfer, Rev. Mod. Phys. \textbf{87}, 765 (2015); [3] W. R. Johnson \textit{et. al}, Phys. Rev. A \textbf{25}, 337 (1982); [4] W. R. Johnson, C. D. Lin, Phys. Rev. A \textbf{20}, 964 (1979); [5] A. R. P. Rau and U. Fano, Phys. Rev. \textbf{167}, 7 (1968). [Preview Abstract] 

D1.00055: TIME RESOLVED MOLECULAR DYNAMICS AND FEMTOCHEMISTRY 

D1.00056: Threedimensional momentum imaging of delayed dissociation of metastable molecular ions Y. Malakar, Bethany Jochim, Reid Erdwien, K. D. Carnes, W. L. Pearson, A. Rudenko, I. BenItzhak Coincidence threedimensional momentum imaging has been a powerful technique in studies of molecular fragmentation following ionization by ultrashort intense laser pulses, fast ion or electron impact, etc. On occasion, the fragmentation process of the intermediate molecular ion can be delayed by a significant fraction of the flight time to the detector due to the presence of metastable states. We focus on the signatures of delayed dissociation into an ion pair observed in coincidence spectra obtained using cold target recoil ion momentum spectrometry (COLTRIMS). Moreover, we present a method for recovering the complete 3D momenta of the dissociating fragments as well as the time delay of the dissociation. Laserinduced dissociation of hydrocarbon dications, for example C$_2$H$_4^{2+}$ $\rightarrow$ H$^+$ + C$_2$H$_3^+$, is used to demonstrate the method. [Preview Abstract] 

D1.00057: Coherent control of charge exchange in strongfield dissociation of LiF Greg Armstrong, Brett Esry The alkalimetalhalides family of molecules are useful prototypes in the study of laserassisted charge exchange. Typically these molecules possess a fieldfree crossing between the ionic and covalent diabatic BornOppenheimer potential curves, leading to Li$^+$ + F$^$ and Li + F in LiF. These channels are energetically wellseparated from higherlying potentials, and may be easily distinguished experimentally. Moreover, charge exchange involves nonadiabatic transitions between the ionic and covalent channels, thereby allowing the investigation of physics beyond the BornOppenheimer approximation. The focus of this work is to control the preference between ionic and covalent dissociative products. We solve the timedependent Schr\"{o}dinger equation for the nuclear motion in full dimensionality, and investigate a pumpprobe scheme for chargeexchange control [1]. The degree of control is investigated by calculating the kineticenergy release spectrum as a function of pumpprobe delay for the ionic and covalent fragments. This work is supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. [1] B. Rigsbee, Master's Thesis, Kansas State University (2015). [Preview Abstract] 

D1.00058: Development of MultiColor TimeResolved Spectroscopy Methods for Investigating Molecular Systems Kirk Larsen, Elio Champenois, Travis Wright, James Cryan, Niranjan Shivaram, Dipanwita Ray, Tyler Troy, Biswajit Bandyopadhyay, Oleg Kostko, Bruce Rude, Musa Ahmed, Ali Belkacem, Dan Slaughter Ultrafast transient absorption spectroscopy facilitates the study of a system’s electronic excited state dynamics. Employing a multicolor technique, the time evolution of excited states of a given target can be investigated in great detail. We have developed methods for performing multicolor experiments using a femtosecond UV (266nm) pulse obtained from a frequency tripled IR (800nm) pulse, in conjunction with soft xrays from the synchrotron at the Advanced Light Source (ALS). We are additionally working towards developing similar techniques with multicolor, multipulse schemes using extreme ultraviolet light from a high harmonic generation (HHG) source as a probe. We also present reflectivity measurements of different mirror coatings, that allow us to select relevant energies from the HHG source. [Preview Abstract] 

D1.00059: Fewfemtosecond sensitivity of ultrafast molecular dynamics with timeresolved photoelectron spectra Elio G. Champenois, James P Cryan, Kirk Larsen, Niranjan H. Shivaram, Ali Belkacem We explore ultrafast dynamics involving nonadiabatic couplings following valence electronic excitation of small molecular systems. By measuring the timeresolved photoelectron spectra (TRPES) resulting from ionization with ultraviolet light, the excited wave packet can be tracked with state specificity. If the nuclear motion is dominated by a limited number of degrees of freedom, the TRPES also yields information about the molecular geometry. Even with limited temporal resolution, the onset times of the signal at different photoelectron energies can lead to fewfemtosecond sensitivity. Applying this technique to ethylene (C$_2$H$_4$) excited to the $\pi\pi^*$ state, ultrafast motion along the twist coordinate is observed along with transient population to the $\pi3s$ state through nonadiabatic coupling. [Preview Abstract] 

D1.00060: STRONG FIELD PHYSICS 

D1.00061: Role of quantum trajectory in highorder harmonic generation in the Keldysh multiphoton regime PengCheng Li, ShihI Chu We present a systematic study of quantumtrajectory analysis of highorder harmonic generation (HHG) by solving accurately the timedependent Schr$\backslash $"odinger equation for a hydrogen atom in the multiphoton regime where the Keldysh parameter is greater unity. We perform the timefrequency transform to explore the spectral characteristics of the HHG. We find that the timefrequency spectra exhibit a broken distribution at abovethreshold HHG due to the competition associated with the short and longtrajectories when the ionization process is pushed from the multiphoton regime into the tunneling regime, it implies that the harmonic emission in the broken regions of timefrequency spectra are suppressed. In addition, we present a timedependent densityfunctional theory approach for an ab initio study of the effect of correlated multielectron responses on the harmonic emission of Ar atom associated with the quantum trajectories in the multiphoton regime. [Preview Abstract] 

D1.00062: Coherence and quasistable states in a strong infrared field Changchun Zhong, Francis Robicheaux We study the quasistability of UVpulsetrainexcited H atoms in a strong infrared (IR) laser as a function of the phase delay of the UVpulsetrain relative to the IR laser. The UVpulsetrain contains two frequency components. When the two components have frequencies separated by two IR photons, the population of surviving electrons is modulated by up to ten percent. When electrons are excited to right above or below the threshold, the survival probabilities have inverted phase delay dependence which can be explained classically. When the two frequencies are one IRphoton apart, the angular symmetry of the quasistable electrons is broken, and the asymmetry is also controlled by the phase delay. The asymmetrical distribution can be observed while the IR is on and smoothly evolves to a nonzero asymmetry that only weakly depends on the duration of the IR field. [Preview Abstract] 

D1.00063: Greater than two orders of magnitude enhancement of highorder harmonic generation driven by twocolor laser fields\textsuperscript{*} T. Severt, J. Tro\ss, P. Timilisina, G. Kolliopoulos, S. Buczek, C. TralleroHerrero, I. BenItzhak In the past decade, there has been a drive to produce intense tabletop XUV laser sources to study ultrafast dynamics in atoms and molecules. One promising technique is highorder harmonic generation (HHG) driven by twocolor laser fields, which has been shown to enhance the harmonic yield over harmonics generated by only the fundamental singlecolor field, depending on the wavelengths' relationship [1,2]. In preliminary data, we observe more than two orders of magnitude enhancement of harmonics produced by the twocolor (800/400nm) laser field over the 800nm field. We also explore the enhancement's dependence on the relative intensities between the two colors. \newline \newline [1] C. Jin \emph{et al.}, Nat. Comm. \textbf{5}, 4003 (2014).\newline [2] I. J. Kim \emph{et al.}, Phys. Rev. Lett. \textbf{94}, 243901 (2005). \newline \newline \textsuperscript{*}This work and T.S. are partially supported by the National Science Foundation under Award No. IIA1430493. JRML personnel and operations are funded by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office for Science, U.S. Department of Energy. S.B. was also supported by NSFREU program Grant No. PHYS1461251. [Preview Abstract] 

D1.00064: Retrieving plasmonic phase shifts and electricfield enhancements from streaked photoemission spectra of gold nanospheres Jianxiong Li, Uwe Thumm We numerically investigated timeresolved photoemission from gold nanospheres using a quantummechanical approach, including the plasmonic nearfieldenhancement of the streaking field at the surface of the nanosphere. Our simulated streaked photoelectron spectra reveal a nearfield plasmonic amplitude enhancement and phase shift in compared with calculations that exclude the induced plasmonic field. The plasmonic phase shifts we retrieved from the photoelectron spectra agree with the phase shifts near the surface of nanospheres calculated within Mie theory. This suggests the use of streaked photoelectron spectroscopy for retrieving the plasmonic fields near nano particles. [Preview Abstract] 

D1.00065: Size and intensitydependent photoelectron spectra from gasphase gold nanoparticles irradiated by intense femtosecond laser pulse\textbf{s} J. Powell, S.J. Robatjazi, V. Makhija, A. Vajdi, X. Li, Y. Malakar, W.L. Pearson, A. Rudenko, C. Sorensen, J. Stierle, M.F. Kling Nanoparticles bridge the gap between atomic/molecular and bulk matter offering unique opportunities to study light interactions with complex systems, in particular, nearfield enhancements and excitation of plasmons. Here we report on a systematic study of photoelectron emission from isolated gold nanoparticles irradiated by 800 nm, 25 fs laser pulses at 1050 TW/cm$^{2}$ peak intensities. A combination of an aerodynamic lens nanoparticle injector, highenergy velocitymap imaging spectrometer and a highspeed, singleshot camera is employed to record shot by shot photoelectron emission patterns from individual particles. By sorting the recorded images according to the number of emitted electrons, we select the events from the regions of particular laser intensities within the laser focus, thus, essentially avoiding focal volume averaging. Using this approach, we study the intensity and sizedependence of photoelectron energy and angular distributions for particle sizes ranging from 5 nm to 400 nm. [Preview Abstract] 

D1.00066: Classical MonteCarlo simulation for Rydberg states ionization in strong field. Vincent Carrat, Eric Magnuson, Thomas Gallagher The resilience of Rydberg states against ionization has fascinated physicists for a long time. One might expect that the loosely bound electron would be ionized by modest electromagnetic field. However, experiments show that a notable fraction of neutral atoms survive in Rydberg states when exposed to strong microwave or laser fields. Energy transfer between the field and the photoelectron occurs when the electron is close to the ionic core and depends on the phase of the field. Since those states have orbital times that can be larger than the field pulse duration, these energy exchanges will only occur a few times. While we can experimentally control the initial time when we create the Rydberg states and as a consequence the initial energy transfer from the field, our classical calculation suggests that the phase when the electron is returning to the ionic core on the next orbit is chaotic. Statistically the electron only has a 50\% chance to gain energy which may lead to ionization. Additionally the population tends to accumulate in very high n states where ionization is less likely due to fewer rescattering events. Though incomplete, this classical MonteCarlo simulation provides useful insights for understanding the experimental observations. [Preview Abstract] 

D1.00067: Two and threebody fragmentation of CO$_{\mathrm{2}}^{\mathrm{+}}$ induced by intense ultrashort laser pulses Jyoti Rajput, U. Ablikim, M. Zohrabi, Bethany Jochim, Ben Berry, K. D. Carnes, B. D. Esry, I. BenItzhak We have studied the fragmentation dynamics of a CO$_{\mathrm{2}}^{\mathrm{+\thinspace }}$molecularion beam in the strongfield regime using $\ge $32 fs laser pulses (about 795 nm and 1x10$^{\mathrm{16}}$ W/cm$^{\mathrm{2}})$. A coincidence threedimensional momentum imaging method was used to measure all ionic and neutral fragments formed during this multiphoton process. The angular distributions for the dominant twobody fragmentation channels CO$^{\mathrm{+}} \quad +$ O, CO$^{\mathrm{2+\thinspace \thinspace }}+$ O and CO$^{\mathrm{+}} \quad +$ O$^{\mathrm{+}}$ show two features, one predominantly aligned with the polarization axis and the other close to isotropic. The angular distributions for the threebody channels C$^{\mathrm{+}} \quad +$ O$^{\mathrm{+}} \quad +$ O and C$^{\mathrm{+}} \quad +$ O$^{\mathrm{+}} \quad +$ O$^{\mathrm{+}}$, populated via dissociative ionization, show the polarization axis lying preferentially in the molecular plane. We will discuss the kinetic energy release, angular distributions and relative production probability of the observed two and threebody fragmentation channels. [Preview Abstract] 

D1.00068: SCIENCE WITH XUV AND X RAY FREEELECTRON LASERS 

D1.00069: Structures of heterogeneous systems determined using XFEL pulses in the face of radiation damage Linda Young, Phay Ho, Chris Knight, Christoph Bostedt, Gyula Faigl, Miklos Tegze Intense, femtosecond xray freeelectron laser pulses are a promising tool for studying the structure and dynamics of complex systems at atomic resolution.~ Our previous efforts, using an atomistic quantum/classical model to track the dynamical evolution of ions and electrons throughout a femtosecond xray pulse and out to picosecond timescales, focused on quantifying the effects of radiation damage on homogeneous rare gas clusters for imaging applications in an ideal situation.~ In these studies, the entire 3D Qspace scattering pattern was computed and available for reconstruction of the initial structure.~ However, a realistic representation of an experiment would feature a collection of noisy 2D scattering patterns, from which orientation would first be required to generate the 3D Qspace distribution from which solution of the phase problem and reconstruction would then proceed.~ We will present the first results of these efforts on heterogeneous systems. [Preview Abstract] 

D1.00070: Photodetachment of H$^$ from intense, short, highfrequency pulses HuaChieh Shao, F. Robicheaux We study the photodetachment of an electron from the hydrogen anion due to short, highfrequency laser pulses by numerically solving the timedependent Schr\"odinger equation. Simulations are performed to investigate the dependence of the photoelectron spectra on the duration, chirp, and intensity of the pulses. Specifically, we concentrate on the lowenergy distributions in the spectra that result from the Raman transitions of the broadband pulses. Contrary to the onephoton ionization, the lowenergy distribution maintains a similar width as the laser bandwidth is expanded by chirping the pulses. In addition, we study the transitions of the ionization dynamics from the perturbative to strongfield regime. At high intensities, the positions of the net one and twophoton absorption peaks in the spectrum shifts and the peaks split to multiple subpeaks because of the multiphoton effects. Moreover, although the one and twophoton peaks and lowenergy distribution exhibit saturation of the ionization yields, the latter shows relatively mild saturation. [Preview Abstract] 

D1.00071: NEW LIGHT SOURCES, LASER TECHNOLOGY AND SHORT PULSE GENERATION 

D1.00072: Developing a HighFlux Isolated Attosecond Pulse Source Andrei Kamalov, Matthew Ware, Philip Bucksbaum, James Cryan High harmonic based light sources have proven to be valuable experimental tools that facilitate studies of electron dynamics at their natural timescale, the attosecond regime.~~The nature of driving laser sources used in high harmonic generation make it difficult to attain attosecond pulses that are both isolated in time and of a high intensity.~~We present our progress in commissioning a beamline designed to produce highflux isolated attosecond pulses.~~A multistep amplification process provides us with 30 mJ, 25 fs pulses centered around 800 nm with 100 Hz repetition rate.~~These pulses are spatially split and focused into a gas cell.~~A noncollinear optical gating scheme is used to produce a lighthouse source of high harmonic radiation wherein each beamlet is an isolated attosecond pulse.~~A variabledepth grazingincidence stepped mirror is fabricated to extend the optical path length of the older beamlets and thus overlap the beamlets in time.~ The combined beam is tightly focused and ensuing mechanics will be studied with an electron spectrometer as well as a xuv photon spectrometer. [Preview Abstract] 

D1.00073: A highpower incoherent light source for ultraprecise optical trapping Robert Schittko, Anton Mazurenko, Markus Greiner The ability to engineer arbitrary optical potentials using spatial light modulation has opened up exciting possibilities in ultracold quantum gas experiments. Yet, despite the high trap quality currently achievable, interferenceinduced distortions caused by scattering along the optical path continue to impede more sensitive measurements. We present a design of a highpower, spatially and temporally incoherent light source that dramatically reduces the impact of such distortions. The device is based on an array of nonlasing semiconductor emitters mounted on a single chip, whose optical output is coupled into a multimode fiber. The fiber is used to populate a large number of transverse modes, each of which experiences a different optical path length. This effect, combined with the small coherence length of the light, dramatically reduces the spatial coherence of the output. In addition to theoretical calculations showcasing the feasibility of this approach, we present various experimental measurements verifying the low degree of spatial coherence exhibited by the source, including a detailed analysis of the speckle contrast at the fiber end. [Preview Abstract] 

D1.00074: Making custom fiber lasers for use in an atomic physics experiment. Ali Khademian, Garnet Cameron, Kyla Nault, David Shiner Fiber lasers can be a reasonable choice for a laser source in atomic physics. Our particular applications involve the optical pumping and in some applications cooling of various transitions in atomic helium. Doped fiber with emission at the required wavelengths is necessary. Readily available fiber and approximate wavelength emission ranges include Yb (990  1150 nm), Er/Yb (1530  1625 nm) and Th (1900 2100 nm). High efficiency conversion of pump photons into stable single frequency laser emission at the required wavelength is the function of the fiber laser. A simple fiber laser cavity uses a short (\textasciitilde few mm) fiber grating high reflector mirror, a doped fiber section for the laser cavity, and a long (\textasciitilde few cm) fiber grating output coupler. To ensure reliable single frequency operation, the laser cavity length should be within 23 times the output grating length. However the cavity length must be long enough for round trip gains to compensate for the output mirror transmission loss. Efficiency can be maximized by avoiding fiber splices in the fiber laser cavity. This requires that the gratings be written into the doped fiber directly. In our previous designs, back coupling of the fiber laser into the pump laser contributes to instability and sometimes caused catastrophic pump failure. Current designs use a fiber based wavelength splitter (WDM) to study and circumvent this problem. Data will be presented on the fiber lasers at 1083 nm. Work on a Thulium 2057 nm fiber laser will also be discussed. [Preview Abstract] 

D1.00075: MATTER WAVE INTERFEROMETRY 

D1.00076: Development of a BEC interferometer using Painted Potentials E. Carlo Samson, Changhyun Ryu, Malcolm Boshier Due to their compact nature, BEC interferometers make it possible to develop portable precision measurement devices. We are developing a BEC interferometer using the painted potential \footnote{K. Henderson et al., \textit{New J. Phys.} \textbf{11}, 043030 (2009)}, a technique that allows for the creation and manipulation of BECs in arbitrary and dynamic 2D trapping potentials. This technique makes it possible to create BECs in a “U”shaped trap, which is equivalent to two potential wells coupled by a channel. A slow removal of the link allows us to reduce excitations in the BECs typical of splitting processes, while maintaining their phase coherence. We report our measurements of the coherence time after the splitting, and show the growth of the relative phase difference between the two BECs that limits our coherence time. To perform linear acceleration measurements and rotation sensing, it is essential to move the BECs relative to each other. We will present schemes we are developing to transport the two trapped BECs within the coherence time with minimal excitations. [Preview Abstract] 

D1.00077: Towards experimental demonstration of shaken lattice interferometry Carrie Weidner, Hoon Yu, Dana Anderson We report on experimental progress towards performing interferometry using atoms trapped in an optical lattice. That is, we load Rb87 atoms into the ground state of a reddetuned optical lattice potential $V(x) = V_0\cos[2kx + \phi(t)]$. By changing $\phi(t)$, we wish to implement the standard interferometric sequence of beam splitting, propagation, reflection, reverse propagation, and recombination. In order to find the desired $\phi(t)$, we implement a closedloop learning algorithm [1] which provides a guess for $\phi(t)$, analyzes experimental data, then modifies the guess in order to converge upon an optimal shaking function that results in transformation of the initial wavefunction to the desired atomic state. For example, splitting of the atom wavefunction, with equal populations of atoms in the $\pm2\hbar k$ momentum states may be implemented. The experimental implementation of such a system is described and progress towards the full interferometric sequence is detailed. [1] T. Caneva \textit{et.al}. PRA 84, 022326, (2011). [Preview Abstract] 

D1.00078: QUANTUM/COHERENT CONTROL 

D1.00079: Active Cancellation of Acoustical Resonances with an FPGA FIR Filter Albert Ryou, Jonathan Simon We demonstrate a novel approach to enhancing the closedloop bandwidth of a feedbackcontrolled mechanical system by digitally cancelling its acoustical resonances and antiresonances with an FPGA FIR filter. By performing a realtime convolution of the feedback error signal with an arbitrary filter, we can suppress arbitrarily many poles and zeros below 100 kHz, each with a linewidth as small as 10 Hz. We demonstrate the efficacy of this technique by cancelling the six largest resonances and antiresonances of a highfinesse optical resonator piezomechanical transfer function, thereby enhancing the unity gain frequency by more than an order of magnitude. More broadly, this approach is applicable to stabilization of optical resonators, external cavity diode lasers, and scanning tunneling microscopes. [Preview Abstract] 

D1.00080: Discrimination of coherence effect in electromagnetically induced transparency in Vtype systems of Rb atoms HyunJong Kang, Seung Chul Yang, HeungRyoul Noh An experimental and theoretical study of electromagnetically induced transparency (EIT) in Vtype systems of Rb atoms is presented. The frequency of the probe beam is locked to one of the resonance lines in the D1 line, whereas that of the coupling beam is scanned around the D2 line. We study the dependence of polarizations of the coupling and probe beams by varying the laser intensities. The experimental results are compared with the results calculated from the accurate density matrix equations. We also discriminate the portion of coherence effect in the calculated EIT spectra. [Preview Abstract] 

D1.00081: Electron Confinement in Cylindrical Potential Well A. S. Baltenkov, A. Z. Msezane We show that studying the solutions of the wave equation for an electron confined in a cylindrical potential well offers the possibility to analyze the confinement behavior of an electron executing one or twodimensional motion in the remaining threedimensional space within the framework of the same mathematical model of the potential well. Some lowlying electronic states with different symmetries are considered and the corresponding wave functions are calculated. The behavior of their nodes and their peak positions with respect to the parameters of the cylindrical well is analyzed. Additionally, the momentum distributions of electrons in these states are calculated. The limiting cases of the ratio of the cylinder length $H$ to its radius $R_{\mathrm{0}}$ are considered; when $H$ significantly exceeds $R_{\mathrm{0}}$ and when $R_{\mathrm{0\thinspace }}$is much greater than $H$. The possible application of the results obtained here for the description of the general features in the behavior of electrons in nanowires with metallic type of conductivity (or nanotubes) and ultrathin epitaxial films (or graphene sheets) are discussed. Possible experiments are suggested as well where the quantum confinement can be manifested. [Preview Abstract] 

D1.00082: Towards Long Range SpinSpin Interactions via Mechanical Resonators Aaron Kabcenell, Jan Gieseler, Arthur Safira, Shimon Kolkowitz, Alexander Zibrov, Jack Harris, Mikhail Lukin Nitrogen vacancy centers (NVs) are promising candidates for quantum computation, with room temperature optical spin readout and initialization, microwave manipulability, and weak coupling to the environment resulting in long spin coherence times. The major outstanding challenge involves engineering coherent interactions between the spin states of spatially separated NV centers. To address this challenge, we are working towards the experimental realization of mechanical spin transducers. We have successfully fabricated magnetized high quality factor (Q\textgreater 10$^{\mathrm{5}})$, doublyclamped silicon nitride mechanical resonators integrated close to a diamond surface, and report on experimental progress towards achieving the coherent coupling of the motion of these resonators with the electronic spin states of individual NV centers under cryogenic conditions. Such a system is expected to provide a scalable platform for mediating effective interactions between isolated spin qubits. [Preview Abstract] 

D1.00083: Quantum state control of trapped Holmium atoms James Hostetter, Christopher Yip, William Milner, Donald Booth, Jeffrey Collett, Mark Saffman Neutral Holmium with its large number of hyperfine ground states provides a promising approach for collective encoding of a multiqubit register. A prerequisite for collective encoding is the ability to prepare different states in the 128 state hyperfine ground manifold. We report progress towards optical pumping and control of the hyperfine Zeeman state of trapped Ho atoms. Atoms are transferred from a 410.5 nm MOT into a 455 nm optical dipole trap. The atoms can be optically pumped using light driving the ground $6s^2, F=11$ to $6s6p, F'=11$ transition together with a $F=10$ to $F'=11$ repumper. Microwave fields are then used to drive transitions to hyperfine levels with $4\le F\le 11$. [Preview Abstract] 

D1.00084: Solving the quantum brachistochrone equation through differential geometry Chenglong You, Mark Wilde, Jonathan Dowling, Xiaoting Wang The ability of generating a particular quantum state, or model a physical quantum device by exploring quantum state transfer, is important in many applications such as quantum chemistry, quantum information processing, quantum metrology and cooling. Due to the environmental noise, a quantum device suffers from decoherence causing information loss. Hence, completing the stategeneration task in a timeoptimal way can be considered as a straightforward method to reduce decoherence. For a quantum system whose Hamiltonian has a fixed type and a finite energy bandwidth, it has been found that the timeoptimal quantum evolution can be characterized by the quantum brachistochrone equation (PRL, 96, 060503 (2006)). In addition, the brachistochrone curve is found to have a geometric interpretation: it is the limit of a oneparameter family of geodesics on a subRiemannian model (PRL 114, 170501 (2015)). Such geodesicbrachistochrone connection provides an efficient numerical method to solve the quantum brachistochrone equation. In this work, we will demonstrate this numerical method by studying the timeoptimal stategenerating problem on a given quantum spin system. We also find that the Pareto weightedsum optimization turns out to be a simple but efficient method in solving the quantum timeoptimal problems. [Preview Abstract] 

D1.00085: Persistent atomic spin squeezing at the Heisenberg limit LingNa Wu, Meng Khoon Tey, Li You Oneaxis twisting (OAT) and twoaxis counter twisting (TACT) are two widely discussed processes capable of dynamically generating spin squeezed states, which have potential applications to precision measurement and entanglement detection. TACT provides better spin squeezing (SS), but has not been demonstrated as its form of interaction does not occur naturally in known physical systems. Several proposals for realizing effective TACT transformed from OAT require stringent experimental conditions, in order to overcome the problems of nonstationary (oscillating) SS and continuously varying mean spin direction. We report a simple protocol that solves both problems by freezing SS at an optimal point and realizing effectively persistent SS by inhibiting further squeezing dynamics. Explicit procedures are outlined which favorably relax experimental demands and significantly brighten the prospects for realizing TACT. [Preview Abstract] 

D1.00086: Universal control of an oscillator with dispersive coupling to a qubit Stefan Krastanov, Reinier Heeres, Philip Reinhold, Victor V. Albert, Chao Shen, ChangLing Zou, Brian Vlastakis, Robert Schoelkopf, Liang Jiang We investigate quantum control of an oscillator mode that dispersively couples to an ancillary qubit. In the strong dispersive regime, we may drive the qubit conditioned on the selected number states of the oscillator, which enables selective numberdependent arbitrary phase (SNAP) operation and universal control of the oscillator. We provide explicit constructions for arbitrary state preparation and arbitrary unitary operation of the oscillator. Moreover, using optimal control techniques, we develop fast and efficient pulse sequences to achieve high fidelity unitary gates. This universal control scheme of the oscillator can readily be implemented using superconducting circuits. [Preview Abstract] 

D1.00087: Stabilization and feedback control of weak measurement monitored quantum oscillators Hermann Uys, Pieter du Toit, Shaun Burd, Thomas Konrad We study feedback control of quantum oscillators, monitored through periodic weak measurement. By implementing reversals of measurement perturbations based on a Bayesian estimate of the state dynamics, we demonstrate suppressed measurement noise leading to greater oscillator stability and improved quantum feedback control. [Preview Abstract] 

D1.00088: Scattering of Ultracold Atoms from an Oscillating Barrier Andrew Pyle, Charles Fancher, Megan Ivory, Kunal Das, Tommy Byrd, Kevin Mitchell, John Delos, Seth Aubin We present progress on an experiment to study 1D quantum mechanical scattering by an amplitudemodulated barrier. The barrier oscillating at frequency $\omega $ imparts or subtracts kinetic energy in discrete amounts from the scattered atoms. Simulations confirm that the atomic energy spectrum resembles a comb with a tooth spacing of $\hbar \omega $. We present an atom chipbased system to study the scattering dynamics with BoseEinstein condensates (BEC). A BEC is released from an optical dipole trap, while a modulated magnetic field gradient controls the vertical motion of the BEC as it travels towards a focused laser beam that serves as the barrier. Detection is carried out with a time of flight technique to resolve discrete atomic sidebands. This is a first step towards implementing a pump with atoms based on two such barriers modulated out of phase with one another. Ballistic quantum pumping was originally proposed for ballistic electron transport in nanowires, but has proven difficult to implement. The atomic approach is a route around the bottleneck in solid state systems, as optical superlattice experiments have recently confirmed. Work supported by W{\&}M. [Preview Abstract] 

D1.00089: Quantum beats in the field ionization of Rydberg atoms in the presence of magnetic fields Vincent C. Gregoric, Hannah Hastings, Thomas J. Carroll, Michael W. Noel By exciting a coherent superposition and varying its phase evolution, quantum beats in the selective field ionization of Rydberg atoms have been observed [R. Feynman, et al., \textit{PRA}, \textbf{92}, 043412 (2015)]. Here, we present a study exploring the effect of electric and magnetic fields on quantum beats. Beginning with a single excited state, a coherent superposition is created by a short electric field pulse in the presence of a static magnetic field. The resulting quantum beats are then observed in the field ionization spectrum. Additionally, millimeterwave spectroscopy is used to probe the state populations in this superposition. [Preview Abstract] 

D1.00090: Optical Control of Electrons in Au Nanowires Eric Jones, Gobind Basnet, Wayne Huang, Bret Flanders, Herman Batelaan Gold nanowires [1],~with diameters less than 100 nm, are novel sources for electron field emission. Their geometry confines the propagation of conduction electrons, giving rise to effects not seen in the bulk, such as ballistic currents and surface plasmon polaritons (SPPs)~[2]. Dynamics within the wire are probed with laserinduced field emission from the nanowire tip. A balanced MachZehnder interferometer is used to split and delay pulses up to 170 ps from a Ti:Saph oscillator (800 nm, 50 fs) in a pumpprobe scheme. The output beamsplitter of the interferometer is mounted on a translation stage to control the separation of the pump and probe beams with submicron precision. The beams are focused to 3 $\mu $m spots on the tip and shaft of a nanowire, mounted under vacuum at 2\times 10$^{\mathrm{7}}$ mTorr, by an offaxis parabolic mirror. Fieldemitted electrons are counted by a channel electron multiplier. We discuss experimental results of our pumpprobe experiments taken at different pump positions. Optical control of electron dynamics within these nanowires may lead to a truly ondemand source of single and multiple electron pulses. [1] B. Ozturk, I. Talukdar, and B. N. Flanders, Nanotechnology \textbf{18}, 365302 (2007). [2] B. Barwick, D. J. Flannigan, and A. H. Zewail, Nature \textbf{462}, 902 (2009). [Preview Abstract] 

D1.00091: Ultrafast state detection and 2D ion crystals in a Paul trap Michael Ip, Anthony Ransford, Wesley Campbell Projective readout of quantum information stored in atomic qubits typically uses statedependent CW laserinduced fluorescence. This method requires an often sophisticated imaging system to spatially filter out the background CW laser light. We present an alternative approach that instead uses simple pulse sequences from a modelocked laser to affect the same statedependent excitations in less than 1 ns. The resulting atomic fluorescence occurs in the dark, allowing the placement of nonimaging detectors right next to the atom to improve the qubit state detection efficiency and speed. We also study 2D Coulomb crystals of atomic ions in an oblate Paul trap. We find that crystals with hundreds of ions can be held in the trap, potentially offering an alternative to the use of Penning traps for the quantum simulation of 2D lattice spin models. We discuss the classical physics of these crystals and the metastable states that are supported in 2D. This work is supported by the US Army Research Office. [Preview Abstract] 

D1.00092: AC Stark effect in a spinorbit mixed quantum states in a fivelevel molecular system coupled by three lasers Jianbing Qi The interaction of the spin orbital motion of electrons can mix quantum states with different spin multiplicity. Thus the mixed states can carry both characteristics of the two states depending on the mixing coefficients. The spinorbit coupled rovibrational levels in diatomic alkali are ubiquitous. These levels are classified as singlet states (if the total spin is zero) and triplet states (if the total spin is one), respectively. A transition from a singlet level can only go to singlet levels and a triplet only to triplet levels. The spinorbit coupled states can be used as a gateway to access some normally prohibited transitions. By coupling the mixed states to an auxiliary quantum state with lasers, the coupling coefficient of two mixed singlettriplet molecular states can be modified by ac Stark effect via varying the Rabi frequency of the coupling lasers and the detuning of the laser frequency, We use density matrix equations and a fivelevel molecular model to show that a coupled singlettriplet pair of rovibrational levels can be used as a channel to enhance the probability of accessing target quantum states. [Preview Abstract] 

D1.00093: QUANTUM MEASUREMENT 

D1.00094: Nonlinear phonon interferometry at the Heisenberg limit Hil F. H. Cheung, Yogesh Sharad Patil, Laura Chang, Srivatsan Chakram, Mukund Vengalattore Interferometers operating at or close to quantum limits of precision have found wide application in tabletop searches for physics beyond the standard model, the study of fundamental forces and symmetries of nature and foundational tests of quantum mechanics. The limits imposed by quantum fluctuations and measurement backaction on conventional interferometers ($\delta \phi\sim1/\sqrt{N}$) have spurred the development of schemes to circumvent these limits through quantum interference, multiparticle interactions and entanglement. Here, we realize a prominent example of such schemes, the socalled SU(1,1) interferometer, in a fundamentally new platform in which the interfering arms are distinct flexural modes of a millimeterscale mechanical resonator [1]. We realize up to 15.4(3) dB of noise squeezing and demonstrate the Heisenberg scaling of interferometric sensitivity ($\delta \phi\sim1/N$), corresponding to a 6fold improvement in measurement precision over a conventional interferometer. We describe how our work extends the optomechanical toolbox and how it presents new avenues for studies of optomechanical sensing and studies of nonequilibrium dynamics of multimode optomechanical systems.\\[4pt] [1] H. F. H. Cheung \em et al. \em\ arXiv:1601.02324 (2016) [Preview Abstract] 

D1.00095: Dependence of NVEnsemble T2* on Applied Magnetic Field Connor Hart, Erik Bauch, John Barry, Jennifer Schloss, Matthew Turner, Ronald Walworth In measurements using ensembles of nitrogen vacancy (NV) centers in diamond,~the magnetic field sensitivity can be improved by~increasing the NV spin dephasing time, T2*.~ For NV ensembles, T2* is limited by inhomogeneous broadening arising from variations in the local environment sensed by individual NVs, such as magnetic fields and strain. Here, we describe a systematic study of parameters influencing the~NV ensemble~T2*, and efforts to mitigate sources~of inhomogeneity. In particular, we report a nontrivial dependence of T2* on applied external magnetic field.~These results suggest new pathways to improving the sensitivity of NVensemble magnetometry.~ [Preview Abstract] 

D1.00096: Generalized quantum measurements on a $^{87}$Rb BoseEinstein condensate Joseph D. Murphree, Azure Hansen, Justin T. Schultz, Maitreyi Jayaseelan, Nicholas P. Bigelow We investigate two applications of generalized measurements on a $^{87}$Rb BoseEinstein condensate (BEC). The first involves preparing the BEC in one of two nonorthogonal states constructed from a superposition of two atomic spin states. A positiveoperator valued measure (POVM) for this system can be defined by three vectors in the 2D spin space. A twophoton Raman process rotates these vectors into a higherdimensional space associating each with its own spin state, whose relative populations are measured using SternGerlach imaging. This allows the possibility of unambiguously determining in which state the system was prepared. For the second application, a superposition of two spin states is used to put the BEC into one of three nonorthogonal states in the trine state configuration and measured using a POVM as before. Here an unambiguous measurement is impossible, but the POVM minimizes the error probability, improving upon the error probability associated with a traditional projective von Neumann measurement. Finally, incorporating orbital angular momentum states of the BEC allows for the possibility of extending these techniques into higher dimensions. [Preview Abstract] 

D1.00097: Measurement of topological invariants with spin qubits in diamond Keigo Arai, Junghyun Lee, Chinmay Belthangady, Ronald Walsworth We present our recent measurements on topological invariants using a single spin qubit in diamond. The ground states of nitrogenvacancy (NV) color centers in diamond are used as an ideal qubit whose states can be fully controlled via the microwave frequency detuning, amplitude, and relative phase. Manipulating these parameters on a closed manifold, we study the topological invariants of three NV hyperfine states, which are topologically identical to a three interacting qubit system in the relevant parameter space. Finally, we construct a 2D topological phase diagram of the three interacting qubit system. [Preview Abstract] 

D1.00098: Towards a spin radar with Nitrogen Vacancy centers in diamond Ashok Ajoy, YiXiang Liu, Paola Cappellaro Nitrogen Vacancy (NV) centers in diamond are a promising platform for nanoscale magnetic resonance imaging. The NV spin can be used to sense the presence of external nuclear spins, and through them biomolecule structure, by exploiting anisotropic hyperfine interactions. The NV center thus effectively acts as a dipole "antenna", detecting and identifying spins at different spatial locations. The antenna dipole is typically set by the diamond and target sample geometry, and nuclear spins are often found in the NV’s dipole blind spot. In this work, we demonstrate an experimental technique by which one can controllably turn and manipulate the direction of this effective NV antenna over a wide range of approximately +40 degrees. In combination with filtered back projection techniques, this method allows reconstructing with high resolution the real space position of spins in the NV center environment. [Preview Abstract] 

D1.00099: Advances in Spin Squeezing Baochen Wu, Kevin C. Cox, Graham P. Greve, James K. Thompson Joint or collective measurements of many atoms are becoming a promising avenue for creating large amounts of quantum entanglement useful for precision measurement. We review recent results from experiments with large ensembles of lasercooled Rb atoms where we directly observe up to 59(8) times (17.7(6) dB) improvement in quantum phase variance relative to the standard quantum limit (known as spin squeezing), deterministically steer to an entangled spin state via realtime feedback, and explore prospects for realizing entanglement in free space by means of homogeneous coupling. [Preview Abstract] 

D1.00100: Coherent manipulation of an ensemble of nuclear spins in diamond for high precision rotation sensing JeanChristophe Jaskula, Kasturi Saha, Ashok Ajoy, Paola Cappellaro Gyroscopes find wide applications in everyday life from navigation and inertial sensing to rotation sensors in handheld devices and automobiles. Current devices, based on either atomic or solidstate systems, impose a choice between longtime stability and high sensitivity in a miniaturized system. We are building a solidstate spin gyroscope associated with the NitrogenVacancy (NV) centers in diamond take advantage of the efficient optical initialization and measurement offered by the NV electronic spin and the stability and long coherence time of the nuclear spin, which is preserved even at high defect density. In addition, we also investigate electromagnetic noise monitoring and feedback schemes based on the coupling between the NV electronic and nuclear spin to achieve higher stability. [Preview Abstract] 

D1.00101: MANYBODY PHYSICS IN QUANTUM SIMULATION 

D1.00102: Supermodepolariton condensation in a multimode cavity QEDBEC system Alicia Kollar, Alexander Papageorge, Yudan Guo, Varun Vaidya, Benjamin Lev Investigations of manybody physics in an AMO context often employ a static optical lattice to create a periodic potential. Such systems, while capable of exploring, e.g., the Hubbard model, lack the fully emergent crystalline order found in solid state systems whose stiffness is not imposed externally, but arises dynamically. Our multimode cavity QED experiment is introducing a new method of generating fully emergent and compliant optical lattices to the ultracold atom toolbox and provides new avenues to explore quantum liquid crystalline order. We will present our first experimental result, the first observation of a supermodepolariton condensate via a supermode superradiant phase transition. [Preview Abstract] 

D1.00103: Towards quantum manybody physics with Sr in optical lattices Sebastian Blatt, Nejc Jansa, Rodrigo G. Escudero, Andr{\'e} Heinz, Annie Jihyun Park, Stepan Snigirev, Jean Dalibard, Immanuel Bloch Within the last decade, fermionic alkaline earth atoms in optical lattices have become a platform for precision measurements, culminating in the realization of an atomic clock with the currently highest stability and accuracy at the $2 \times 10^{18}$ level. In the meantime, quantum degenerate gases of all bosonic and fermionic isotopes of Sr have been realized. With the extension of the quantum gas microscopy technique to fermionic alkali metal atoms, experiments with quantum degenerate gases in optical lattices have taken another step towards full control over the internal and external degrees of freedom of fermions in optical lattices. Here, we report on the construction of a new experiment with quantum degenerate gases of Sr in optical lattices. Our experiment aims to combine the high spatial control over the atomic degrees of freedom from quantum gas microscopy with the precision control over the internal degrees of freedom enabled by optical lattice clock techniques. [Preview Abstract] 

D1.00104: Spin dynamics and Kondo physics in optical tweezers Yiheng Lin, Brian J. Lester, Mark O. Brown, Adam M. Kaufman, Junling Long, Randall J. Ball, Leonid Isaev, Michael L. Wall, Ana Maria Rey, Cindy A. Regal We propose to use optical tweezers as a toolset for direct observation of the interplay between quantum statistics, kinetic energy and interactions, and thus implement minimum instances of the Kondo lattice model in systems with few bosonic rubidium atoms. By taking advantage of strong local exchange interactions, our ability to tune the spindependent potential shifts between the two wells and complete control over spin and motional degrees of freedom, we design an adiabatic tunneling scheme that efficiently creates a spinsinglet state in one well starting from two initially separated atoms (one atom per tweezer) in opposite spin state. For three atoms in a doublewell, two localized in the lowest vibrational mode of each tweezer and one atom in an excited delocalized state, we plan to use similar techniques and observe resonant transfer of twoatom singlettriplet states between the wells in the regime when the exchange coupling exceeds the mobile atom hopping. Moreover, we argue that such threeatom doubletweezers could potentially be used for quantum computation by encoding logical qubits in collective spin and motional degrees of freedom. [Preview Abstract] 

D1.00105: Progress towards realization of a Quantum Matter Synthesizer Gustaf Downs, Jonathan Trisnadi, Cheng Chin We present our recent progress towards building a new type of optical lattice experiment. Once completed, the Quantum Matter Synthesizer (QMS) will be able to load atoms into a fardetuned lattice projected through a high numerical aperture objective lens, image the atomic distribution and cool the atoms to the vibrational ground state, and then dynamically turn off and rearrange lattice sites to achieve the desired filling fraction and spin order. We will achieve this dynamically rearrangeable lattice by forming our 2D optical potential with Digital Micromirror Devices (DMD). Here we report the performance of our MOT and initial dRSC, our scheme for transporting atoms from our chamber into our highresolution imaging glass cell, and our structural design for stabilizing and isolating critical optical components near the glass cell as well as science goals. [Preview Abstract] 

D1.00106: INTERFACTING NANOPHYSICS AND PLASMONICS WITH COLD ATOMS 

D1.00107: Quantum optical switch controlled by a color center in a diamond nanocavity Alp Sipahigil, Ruffin E. Evans, Denis D. Sukachev, Michael J. Burek, Christian N. Nguyen, Johannes Borregaard, Mihir K. Bhaskar, Haig Atikian, Jose L. Pacheco, Ryan M. Camacho, Fedor Jelezko, Edward Bielejec, Hongkun Park, Marko Loncar, Mikhail D. Lukin Efficient interfaces between photons and quantum emitters form the basis for quantum networks and enable nonlinear optical devices operating at the singlephoton level. By coupling siliconvacancy (SiV) color centers to a diamond nanophotonic device, we realize a quantum optical switch controlled by a single atomlike crystal defect. In our approach, SiV centers are deterministically positioned in diamond photoniccrystal cavities using targeted silicon implantation. We observe that the cavity transmission is substantially attenuated by a single SiV center, is nonlinear at less than one photon per system's bandwidth and can be switched by optically controlling SiV metastable orbital states. Photon correlation measurements are used to verify optical switching at the singlephoton level. Our approach enables the realization of fully integrated, scalable nanophotonic quantum devices. [Preview Abstract] 

D1.00108: Highly nonlocal optical nonlinearities in atoms trapped near a waveguide Ephraim Shahmoon, Pjotrs Grisins, Hans Peter Stimming, Igor Mazets, Gershon Kurizki Nonlinear optical phenomena are typically local. Here we predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nanowaveguide, where longrange interactions between the atoms can be tailored. When the atoms are in an electromagneticallyinduced transparency configuration, the atomic interactions are translated to longrange interactions between photons and thus to highly nonlocal optical nonlinearities. We derive and analyze the governing nonlinear propagation equation, finding a rotonlike excitation spectrum for light and the emergence of longrange order in its output intensity. These predictions open the door to studies of unexplored wave dynamics and manybody physics with highlynonlocal interactions of optical fields in one dimension. [Preview Abstract] 

D1.00109: Development of neutral atom traps based on a microfabricated waveguide YuanYu Jau, Jongmin Lee, Grant Biedermann, Aleem Siddiqui, Matt Eichenfield, Erica Dougla Implementation of trapping neutral atoms in the evanescent fields generated by a nanostructure, such as a nanofiber or a microfabricated nanowaveguide, will naturally enable strong atomphoton interactions, which serve the key mechanisms for different type of quantum controls. At Sandia National Labs, we are aiming to develop a platform based on this concept to eventually trap cesium atoms with a microfabricated waveguide. Although, neutral atom traps using optical nanofiber has been demonstrated, there are several key issues that need to be resolved to realize trapping atoms with microfabricated structure. The subjects include the material for making the waveguide, optical power handling capability, surface adsorption of alkalimetal atoms, surface roughness of the nanostructure, coldatom source for loading the atoms into the evanescentfield traps, etc. We will discuss our studies on these related subjects and report our latest progress. [Preview Abstract] 

D1.00110: Optical characteristics of silicon nitride integrated waveguides for atom trapping Fredrik Fatemi, Marcel Pruessner, Rita Mahon, Doewon Park, Dmitry Kozak, Blake Simpkins, Jed Ziegler, Todd Stievater A number of recent experiments have demonstrated enhanced atomlight interactions by confining atoms in the evanescent field of optical nanofibers (ONF). To achieve a scalable, robust, and versatile platform analogous to ONFs, integrated waveguide approaches are being pursued. However, although the fundamental confinement principle in integrated waveguides is the same as in ONFs, the optical characteristics of these waveguides can be substantially different. In this work, we investigate experimentally and numerically birefringence in subwavelength silicon nitride rib waveguides suitable for atom trapping. We use both near and farfield imaging techniques to measure beat lengths between propagating modes, and show that typical waveguide geometries lead to high birefringence between the lowest order modes not observed in ONFs. These beat lengths can be only a few optical wavelengths long. We discuss the impact of this high birefringence, and show how it can be used to tailor novel trapping geometries. [Preview Abstract] 

D1.00111: COLD RYDBERG GASES AND PLASMAS 

D1.00112: Transition rates in proton  Rydberg atom collisions Daniel Vrinceanu Monte Carlo simulations for energy and angular momentum transfer processes in proton  Ryderg atom collisions were performed and the corresponding rates are reported.The relevance of these rates in the context of cosmological recombination is discussed. The rates are contrasted with the similar rates in electron  Rydberg atom collisions. [Preview Abstract] 

D1.00113: The importance of multilevel Rydberg interaction in electric field tuned F\"orster resonances Jorge Kondo, Donald Booth, Luis Gon\c{c}alves, James Shaffer, Luis Marcassa Manybody physics has been investigated in ultracold Rydberg atom systems, mainly because important parameters, such as density and interaction strength, can be controlled. Several puzzling experimental observations on F\"orster resonances have been associated to manybody effects, usually by comparison to complex theoretical models. In this work, we investigate the dc electric field dependence of 2 F\"orster resonant processes in ultracold $^{85}$Rb, $37D_{5/2}+37D_{5/2}\rightarrow 35L (L=O,Q)+39P_{3/2}$, as a function of the atomic density in an optical dipole trap. At low densities, the $39P$ yield as a function of electric field exhibits resonances. With increasing density, the linewidths increase until the peaks merge. Even under these extreme conditions, where manybody effects were expected to play a role, the $39P$ population depends quadratically on the total Rydberg atom population. In order to explain our results, we implement a theoretical model which takes into account the multilevel character of the interactions and Rydberg atom blockade process using only atom pair interactions. The comparison between the experimental data and the model is very good, suggesting that the F\"orster resonant processes are dominated by 2body interactions. [Preview Abstract] 

D1.00114: Longitudinally homogeneous medium of tunable length for Rydberg EIT Steffen Schmidt, Daniel Tiarks, Giovanni Girelli, Stephan D\"urr, Gerhard Rempe In electromagnetically induced transparency (EIT), an initially opaque medium is made transparent for probe light by applying a strong control beam. As this is a quantum interference effect, it relies on the coherence of the system. In Rydberg EIT, the energy of a Rydberg state depends on the density of the surrounding ground state atoms. If the density of ground state atoms is position dependent, then the densitydependent resonance shift causes dephasing which deteriorates the performance of EIT [1]. The transverse inhomogeneity can be suppressed by tightly focusing the light. To avoid problems from a longitudinal inhomogeneity, we prepare a longitudinally homogeneous medium by an appropriate design of an optical dipole trap. The trap has the additional feature that the length of the medium is tunable between 20 and 300 $\mu m$. A long medium makes it possible to remain at low atomic density, so that the dephasing rate is low, and simultaneously to reach high optical depth, so that the effects of Rydberg blockade can be large. \newline [1] S. Baur et al. Phys. Rev. Lett. 112, 073901 (2014). [Preview Abstract] 

D1.00115: Catalysis of Forster Resonances in Rubidium A.L. Win, W.D. Williams, C.I. Sukenik When two ultracold Rydberg atoms collide they may change their quantum state if the total electronic energy of the two atoms before and after the collision is about the same. This process can be made resonant by tuning the energy levels of the atoms with an electric field, via the Stark shift, so that the energy difference between incoming and outgoing channels vanishes. This condition is known as a “Forster resonance.” We have studied a particular Forster resonance in rubidium: 34p + 34p $\rightarrow$ 34s + 35s, by investigating the time dependence of the state change in an ultracold environment. Furthermore, we have added 34d state atoms to the mix and observed an enhancement of 34s atom production. We attribute this enhancement to a catalysis effect whereby the 34d atoms alter the spatial distribution of 34p atoms that participate in the energy transfer interaction. We will present results from the experiment and compare them to model calculations. [Preview Abstract] 

D1.00116: Spin Transport in Ultracold Rydberg Atoms Jacob Hollingsworth, Rick Mukherjee, Thomas Killian, Kaden Hazzard We devise a scheme to use ultracold Rydberg atoms to study models of transport where Rydberg excitations play the role of tunneling particles. In contrast to previous schemes, where ``tunnelings" between atoms separated by a distance $r$ often scale as $1/r^3$, ours scale as $1/r^6$, for which the physics is more similar to shortranged hopping models. We theoretically demonstrate that current experiments exist in a regime that allows significant transport well within the experimental lifetime  several microns in a microsecond, and derive the experimental parameters for strontium atoms that are necessary to access this regime. We also show how disorder may be introduced and controlled precisely via the depth of an applied optical lattice. We explore the dynamics, looking for signatures of ballistic, diffusive, and localized behavior as a function of the types and strength of disorder applied. [Preview Abstract] 

D1.00117: Modeling Anomalous Broadening of Driven, Dissipative Rydberg Systems Jeremy Young, Elizabeth Goldschmidt, Thomas Boulier, Steve Rolston, Trey Porto, Alexey Gorshkov A crucial feature of many current theoretical proposals for driven, dissipative manybody Rydberg systems is the narrow linewidth of the Rydberg states. However, recently it has been observed that spontaneous transitions to nearby Rydberg states can result in observed linewidths orders of magnitude larger than the bare linewidth via dipoledipole interactions. Here, we present our efforts at theoretically modeling the above experiment. We find good agreement with both the scaling behavior of the linewidth and the resonant pumping rate. [Preview Abstract] 

D1.00118: Investigation of shorttime manybody dynamics in multilevel Rydberg systems. Carlos Bracamontes, Jeremy Young, Elizabeth Goldschmidt, Thomas Boulier, Alexey Gorshkov, Steve Rolston, James Porto We present followup work to previous results in which we observe anomalous broadening in a drivendissipative system of Rydberg atoms. We address rubidium atoms in a 3D optical lattice on 5s18s transition and see substantial broadening of this line with increasing excitation strength and atomic density. We attribute the broadening mechanism to dipoledipole interactions with spontaneously populated nearby Rydberg states. This mechanism implies complex dynamics at early times as the contaminant population is built up. A full microscopic model of this manybody multilevel system has proved elusive, but initial experiments to study these dynamics using single photon counting provided qualitative information that was consistent with simple theoretical estimates. We implement optical heterodyne detection for short probe pulses to study this dynamics in depth and gain further understanding of the system. [Preview Abstract] 

D1.00119: What is the electron temperature in a plasma which evolves from a sample of ultracold Rydberg atoms? Duncan Tate, Gabriel Forest, Edwin Ward, Anne Goodsell Dense samples of cold Rydberg atoms evolve rapidly to an ultracold neutral plasma (UNP) due to ionizing collisions mediated by dipole forces, and other mechanisms. The subsequent plasma evolution is mediated by threebody recombination (TBR) of electrons and ions, and electronRydberg collisions, which can lead to deexcitation, excitation, and ionization of the Rydberg atoms. However, in contrast with UNPs formed by direct photoionization, the plasma evolves in the presence of a large reservoir of Rydberg atoms, and we have been investigating how this affects the UNP dynamics. Specifically, we excite cold Rb atoms in a MOT to a selected Rydberg state using a tuneable pulsed laser. We then measure the UNP expansion velocity using the ion timeofflight spectra, as a function of the binding energy of the initial Rydberg state ($E_b = 0  400$ K), and the initial Rydberg density. Preliminary results show that the UNP expansion velocity, which is a manifestation of the effective electron temperature, has only a weak sensitivity to $E_b$, but is strongly dependent on the Rydberg density. [Preview Abstract] 

D1.00120: Simulations of the angular dependence of the dipoledipole interaction among Rydberg atoms Jacob L. Bigelow, Jacob Hollingsworth, Jacob T. Paul, Matan Peleg, Veronica L. Sanford, Thomas J. Carroll, Michael W. Noel The dipoledipole interaction between two Rydberg atoms depends on the relative orientation of the atoms and on the change in the magnetic quantum number. We simulate the effect of this anisotropy on the energy transport in an amorphous many atom system of ultracold Rydberg atoms subject to a homogeneous applied electric field. We consider two experimentally feasible geometries and find that the effects should be measurable in current generation imaging experiments. We also examine evidence for Anderson localization. This work was supported by the National Science Foundation under Grants No. 1205895 and No. 1205897 and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number OCI1053575. [Preview Abstract] 

D1.00121: Electron effective thermalization via noncollisional mechanisms in ultracold neutral plasmas Craig Witte, Jacob Roberts Many ultracold neutral plasmas (UCPs) are formed with nonuniform electron and ion densities. We present the results of a numerical simulation that compares the velocity distribution evolution after UCP formation between uniform and nonuniform density UCPs. We find that the nonuniform density distribution couples electron collective motions in such a way as to alter the effective thermalization of the electrons in the UCP. This is relevant for understanding the establishment of equilibrium in the electron component of UCPs in experimentally relevant conditions. [Preview Abstract] 

D1.00122: Observation of Cavity Rydberg Polaritons Alexandros Georgakopoulos, Ningyuan Jia, Albert Ryou, Nathan Schine, Michael Cervia, Tahoe Schrader, Ariel Sommer, Jonathan Simon We demonstrate hybridization of optical cavity photons with atomic Rydberg excitations using electromagnetically induced transparency (EIT). The resulting dark state Rydberg polaritons exhibit a compressed frequency spectrum and enhanced lifetime indicating strong lightmatter mixing. We study the coherence properties of cavity Rydberg polaritons and identify the generalized EIT linewidth for optical cavities. Strong collective coupling suppresses polariton losses due to inhomogeneous broadening, which we demonstrate by using different Rydberg levels with a range of polarizabilities. Our results point the way towards using cavity Rydberg polaritons as a platform for creating photonic quantum materials. [Preview Abstract] 

D1.00123: COLD AND ULTRACOLD MOLECULES 

D1.00124: Controlled Ensembles of Formaldehyde Molecules at Ultracold Temperatures Martin Zeppenfeld, Alexander Prehn, Martin Ibr\"ugger, Rosa Gl\"ockner, Gerhard Rempe Applications of ultracold molecules such as quantum information processing and quantum controlled chemistry require the preparation of ultracold molecule ensembles with a high level of control over all molecular degrees of freedom. Due to the inability to apply standard atom cooling techniques such as laser cooling to most molecule species, developing new methods is essential. We present a toolbox of techniques developed in our group for controlling molecules. A microstructured electric trap allows us to trap molecules in predominantly homogeneous electric fields with trapping times of up to a minute\footnote{B.G.U. Englert et al., Phys Rev. Lett. {\bf 107}, 263003 (2011).}$^,$\footnote{A. Prehn et al., arXiv: 1511.09427 [physics.atomph] (2015).}. Optical pumping on a vibrational transition allows us to transfer the population from a large number of rotational states to a single rotational $M$sublevel\footnote{R. Gl\"ockner et al., Phys. Rev. Lett. {\bf 115}, 233001 (2015).}. Our experiment provides excellent conditions for precision spectroscopy and investigation of ultracold collisions. [Preview Abstract] 

D1.00125: Internalstate thermometry of cold polyatomic molecules Xing Wu, Thomas Gantner, Sotir Chervenkov, Martin Zeppenfeld, Gerhard Rempe We present a new method for internalstate thermometry of guided polyatomic molecules. Bright beams of polar molecules are produced by a cryogenic buffergas cell and extracted by electrostatic guiding [1]. Their rotationalstate distribution is probed via RFresonant depletion spectroscopy. With the help of a complete trajectory simulation, resolving the guiding efficiency for all the thermally populated states, we are able to determine the internal temperature in the buffergas cell based on the RF depletion spectroscopy. This thermometry method is demonstrated for various regimes of buffergas cooling, beam formation, and for molecular species of different sizes, e.g., $CH_3F$ and $CF_3CCH$. The results provide strong evidence that the collisional relaxation for rotational degrees of freedom is faster than for translational ones. In addition, the relaxation rates for states with different Kquantum number appear to be different.\\ \\ $^1$L.D. van Buuren et al., Phys. Rev. Lett. 102, 033001 (2009) [Preview Abstract] 

D1.00126: A buffer gas cooled beam of barium monohydride Geoffrey Iwata, Marco Tarallo, Tanya Zelevinsky Significant advances in direct laser cooling of diatomic molecules have opened up a wide array of molecular species to precision studies spanning manybody physics, quantum collisions and ultracold dissociation. We present a cryogenic beam source of barium monohydride (BaH), and study laser ablation of solid precursor targets as well as helium buffer gas cooling dynamics. Additionally, we cover progress towards a molecular magnetooptical trap, with spectroscopic studies of relevant cooling transitions in the $B^2\Sigma \leftarrow X^2\Sigma$ manifold in laser ablated molecules, including resolution of hyperfine structure and precision measurements of the vibrational FrankCondon factors. Finally, we examine the feasibility of photo dissociation of trapped BaH molecules to yield optically accessible samples of ultracold hydrogen. [Preview Abstract] 

D1.00127: Quantum Phases of Externally InPlane Polarized HardCore Dipoles on a ZigZag Chain Qingyang Wang, Johanes Otterbach, Susanne Yelin We describe the groundstate phase diagram of externally polarized hardcore dipoles at halffilling moving along a onedimensional zigzag chain. The dipoles are oriented to lie inplane. Together with the geometry of the chain this gives rise to a bondalternating nearest neighbor interaction due to simultaneous attractive and repulsive interactions. By tuning the ratio between the nearestneighbor interaction and hopping, various phases can be accessed by controlling the polarization angle. In ultrastrong coupling limit, the system boils down to frustrated axial nextnearestneighbor Ising (ANNNI) model. An exact phase diagram is shown in this limit. In small coupling limit, we qualitatively discuss the ordering behavior using perturbative effective fieldtheoretic arguments, together with numerical methods. We show that when chain angle is small, the system mostly exhibits BKTtype phase transitions, whereas large chain angle would drive the system into gapped dimerized phase, where the hopping strength is closely related to the orientation of dimerized pairs. [Preview Abstract] 

D1.00128: Molecular spectroscopy for producing ultracold groundstate NaRb molecules Dajun Wang, Mingyang Guo, Bing Zhu, Bo Lu, Xin Ye, Fudong Wang, Romain Vexiau, Nadia BouloufaMaafa, Goulven Qu\'em\'ener, Olivier Dulieu Recently, we have successfully created an ultracold sample of absolute groundstate NaRb molecules by twophoton Raman transfer of weakly bound Feshbach molecules. Here we will present the detailed spectroscopic investigations on both the excited and the rovibrational ground states for finding the twophoton path. For the excited state, we focus on the $A^1\Sigma^+/b^3\Pi$ singlet and triplet admixture. We discovered an anomalously strong coupling between the $\Omega = 0^+$ and $0^$ components which renders efficient population transfer possible. In the ground state, the pure nuclear hyperfine levels have been clearly resolved, which allows us to create molecules in the absolute ground state directly with Raman transfer. [Preview Abstract] 

D1.00129: Quantum Dynamics through Conical Intersections in Heteronuclear AlkaliMetal Trimers Alexander Petrov, Constantinos Makrides, Svetlana Kotochigova Multiparticle potential surfaces have a number of characteristics that are absent from the more familiar twobody potentials of their constituents. Specifically in the case of triatomic alkali systems, the lowest two doublet surfaces are degenerate at specific locations commonly known as conical intersections. The collection of these points of intersection form a “seam” that trace out a line in nuclear space. As the complex propagates along the reaction path, the degeneracy at the seam allows for a radiationless transition between the surfaces. Here we analyze the lower two doublet states of the KRbK trimer. First, we map out the seam of intersections throughout the nuclear space and determine branching vectors that provide an accurate description of spatial derivative couplings in the vicinity of conical intersections and characterize the subsequent dynamics in the immediate region. We also revisit classical simulations of the nuclear motion on multiple surfaces and investigate how chaotic motion on the complex surfaces affect the reaction in the ultracold domain. [Preview Abstract] 

D1.00130: Spectra and Autoionization Lifetimes of LongRange Rydberg Molecular States of $^{85}$Rb$_2$ Ryan Carollo, Edward Eyler, Phillip Gould, William Stwalley We present highresolution autoionization data and modeling of the $7p$ longrange Rydberg molecular states in $^{85}$Rb$_2$. Our process excites a photoassociation resonance in the $1 \, (0_g^)$ state which decays to $v''=35$ and 36 longrange levels of the $a \, ^3 \Sigma _u^+$ state and to the continuum. These bound molecules are then excited via a single UV photon to target states below the $5s + 7p$ asymptote by a frequencydoubled pulseamplified CW laser with narrow linewidth, $\sim150$ MHz. The longrange portion of the bonding potential is formed by the scattering interaction of the Rydberg electron of a perturbed $7p$ atom scattering from a nearby groundstate atom. We use timeofflight to selectively measure molecular ions, which are formed via autoionization. Using a hyperfine model of the $a \, ^3 \Sigma _u^+$ and its coupling to the $X \, ^1\Sigma_g^+$ state\footnote{E. Tiemann, private communication (2015)}, we are able to place an upper limit on the autoionization linewidth of 450 MHz, corresponding to a lifetime $\geq 3.5 \times 10^{10}$ s. Excitedstate hyperfine structure suggests a stilllower linewidth (and thus longer lifetime), but its contribution is not yet fully understood. This work is supported by NSF and AFOSR. [Preview Abstract] 

D1.00131: Enhancement of Ultracold Molecule Formation Using Shaped Nanosecond Frequency Chirps Jennifer Carini, Shimshon Kallush, Ronnie Kosloff, Phillip Gould We demonstrate that judicious shaping of a nanosecondtimescale frequency chirp can dramatically enhance the formation rate of ultracold molecules. Starting with ultracold $^{87}$Rb atoms, we apply pulses of frequencychirped light to first photoassociate the atoms into excited molecules and then, later in the chirp, deexcite these molecules into a high vibrational level of the lowest triplet state. The enhancing chirp shape passes through the absorption and stimulated emission transitions relatively slowly, thus increasing their adiabaticity, but jumps quickly between them to minimize the effects of spontaneous emission. Comparisons with quantum simulations for various chirp shapes support this enhancement mechanism. Schemes for further improvements of the formation rate will also be presented. This work is supported by DOE and BSF. [Preview Abstract] 

D1.00132: Proposal for Laser Cooling of Alkaline Earth Monoalkoxide Free Radicals Louis Baum, Ivan Kozyryev, Kyle Matsuda, John M. Doyle Cold samples of polyatomic molecules will open new avenues in physics, chemistry, and quantum science. Nondiagonal FranckCondon factors, technically challenging wavelengths, and the lack of strong electronic transitions inhibit direct laser cooling of nonlinear molecules. We identify a scheme for optical cycling in certain molecules with six or more atoms. Replacing hydrogen in alcohols with an alkaline earth metal (M) leads to alkaline earth monoalkoxide free radicals (MOR), which have favorable properties for laser cooling. MO bond is very ionic, so the metal orbitals are slightly affected by the nature of R on the ligand. Diagonal FranckCondon factors, laser accessible transitions, and a small hyperfine structure make MOR molecules suitable for laser cooling. We explore a scheme for optical cycling on the $A\X$ transition of SrOCH\textsubscript{3}. Molecules lost to dark vibrational states will be repumped on the $B\X$ transition. Extension to larger species is possible through expansion of the R group since transitions involve the promotion of the metalcentered nonbonding valence electron. We will detail our estimations of the FranckCondon factors, simulations of the cooling process and describe progress towards the Doppler cooling of MOR polyatomics. [Preview Abstract] 

D1.00133: A new apparatus for manipulating polar KRb molecules in an optical lattice. Jacob Covey, Matthew Miecnikowski, Steven Moses, zhengkun Fu, Deborah Jin, Jun Ye Ultracold polar molecules provide new opportunities for investigation of strongly correlated manybody spin systems such as manybody localization and quantum magnetism. Previously, we observed manybody spin dynamics between molecules pinned in an optical lattice, despite a filling fraction of only 5{\%}. We also performed a thorough investigation of the molecule creation process in an optical lattice and improved our filling fraction to 30{\%} by preparing overlapped Mott and band insulators of the initial atomic gases. Now, we have developed a second generation KRb apparatus that will allow application of large, stable electric fields as well as highresolution addressing and detection of polar molecules. We plan to use these capabilities to study nonequilibrium spin dynamics in an optical lattice with nearly single site resolution. We present the status and direction of the second generation apparatus. [Preview Abstract] 

D1.00134: Ultracold molecules from the bottomup Jessie T Zhang, Nicholas R Hutzler, Lee R Liu, Yichao Yu, KangKuen Ni Ultracold polar molecules exhibit strong, longrange, and tunable dipoledipole interactions that may be utilized for a wide range of studies in quantum simulation and quantum information processing. To realize the full potential of these studies, it is desirable to have a low entropy sample of ultracold polar molecules with full control over both internal and external states, as well as interparticle interactions. We work toward this goal with a new, bottomup approach using the highly polar NaCs molecule. The key steps of our scheme are trapping single Na and Cs atoms in optical dipole traps, cooling the atoms to their motional ground state using Raman sideband cooling, and finally coherently transferring them to ground state NaCs molecules via a twophoton process. This approach should enable creation of low entropy samples with full control over all degrees of freedom, as well as realizing the possibility of singlesite readout and manipulation of molecules. [Preview Abstract] 

D1.00135: Buffergas Cooling of Methyltrioxorhenium, a Parity Violation Candidate Precursor Kenneth Wang, Garrett Drayna, Christian Hallas, Sandra Eibenberger, David Patterson Chiral compounds containing heavymetal centers have been suggested as promising candidates for studying parity violation in molecular spectra, due to the strong dependence of the parity violating energy difference with atomic number. Buffer gas cooled molecular samples exhibit low internal temperature and low velocity in the laboratory frame, making them an attractive source for high precision molecular spectroscopy. We demonstrate here the first buffer gas cooling of an organometallic compound, $ \text{CH}_3\text{ReO}_3 $ (MTO). Although MTO is not chiral, it is a precursor to chiral rhenium compounds which are proposed as attractive candidates, due to their stability and low sublimation points, in the search for parity violation in molecular spectra. We propose methods to extend this source into a slow, high flux beam for ultrahigh precision spectroscopy experiments. [Preview Abstract] 

D1.00136: Ultracold photodissociation and progress towards a molecular lattice clock with $^{88}$Sr ChihHsi Lee, Bart McGuyer, Mickey McDonald, Florian Apfelback, Andrew Grier, Tanya Zelevinsky Techniques originally developed for the construction of atomic clocks can be adapted to the study of ultracold molecules, with applications ranging from studies of ultracold chemistry to searches for new physics. We present recent experimental results involving studies of fully quantum stateresolved photodissociation of $^{88}$Sr$_2$ molecules, as well as progress toward building a molecular clock. First, our system has allowed for precise, quantum stateresolved photodissociation studies, revealing not only excellent control over quantum states but also a more accurate way to describe the photodissociation of diatomic molecules and access ultracold chemistry. Second, the molecular clock will allow us to search for a possible time variation of the protonelectron mass ratio. The ``oscillator'' of such a molecular clock would consist of the frequency difference between two lasers driving a twophoton Raman transition between deeply and intermediatelybound rovibrational levels in the electronic ground state. Accomplishing this task requires exploring several research directions, including the precision spectroscopy of bound states and developing tools for the control and minimization of differential lattice light shifts. [Preview Abstract] 

D1.00137: Towards StateResolved Ultracold Chemical Reactions with KRb Molecules Yu Liu, YuTing Chen, William Tobias, KangKuen Ni Ultracold chemistry explores reactions where both the internal and external quantum states of molecules are important and ideally controlled. Ultracold collisions between pairs of $\mathrm{^{40}K^{87}Rb}$ molecules have been studied previously where evidence of bimolecular chemical reactions was observed as twobody losses of $\mathrm{^{40}K^{87}Rb}$. This reaction pathway is expected to yield products $\mathrm{^{40}K_{2}}$ and $\mathrm{^{87}Rb_{2}}$ with 10 $\mathrm{cm^{1}}$ (14.4 K) excess energy. We will present our design and construction of a new apparatus that aims to directly map out the products and their quantum states. The apparatus combines ultracold gases of $\mathrm{K}$, $\mathrm{Rb}$, and $\mathrm{KRb}$ and REMPI (ResonanceEnhanced Multiphoton Ionization) detection capabilities. This apparatus will offer possibilities to study statetostate chemistry, reversibility of chemical reactions, and controllable ultracold reactions. [Preview Abstract] 

D1.00138: Ultracold nonreactive molecules in an optical lattice: connecting chemistry to manybody physics Rick Mukherjee, Kevin Ewart, Shah Alam, Michael Wall, Andris Do\c{c}aj, Kaden Hazzard We derive effective lattice models for ultracold bosonic or fermionic nonreactive molecules (NRMs) in an optical lattice. In stark contrast to the standard Hubbard model, which is commonly assumed to accurately describe NRMs, we find that the single onsite interaction parameter $U$ is replaced by a multichannel interaction. The complex, multichannel collisional physics is unrelated to dipolar interactions, and so occurs even in the absence of an electric field or for homonuclear molecules. We find a crossover between coherent fewchannel models and fully incoherent singlechannel models as the lattice depth is increased. We devise ways to control the effective model parameters using external fields and lattice anisotropy. We show that these parameters can be determined in lattice modulation experiments, which measure molecular collision dynamics with a vastly sharper energy resolution than experiments in an ultracold gas. We will report our progress calculating this novel model's ground state phase diagram. [Preview Abstract] 

D1.00139: Singlettriplet electron scattering admixture due to fine and hyperfine interactions in Cs Rydberg molecules Samuel Markson, Seth Rittenhouse, Hossein Sadeghpour We will present the admixture of singlet electron scattering into the more dominant triplet scattering in the formation of ultracold Cs Rydberg molecules excited into nonzero electronic angular momentum states. This admixture comes about due to both spinorbit (SO) coupling in the Rydberg atom as well as the hyperfine (HF) coupling in the ground state atom. In Cs, the Rydberg SO and ground HF interactions are on par. The interaction between the Rydberg electron and the ground state atom includes both swave and pwave scattering components which can cause additional mixing of electronic Rydberg states in the bound molecules. We intend to apply the formalism to Rydberg excitation in Cs in p and d states and will give a progress report at the meeting. [Preview Abstract] 

D1.00140: Coherent Control of Ground State NaK Molecules Zoe Yan, Jee Woo Park, Huanqian Loh, Sebastian Will, Martin Zwierlein Ultracold dipolar molecules exhibit anisotropic, tunable, longrange interactions, making them attractive for the study of novel states of matter and quantum information processing. We demonstrate the creation and control of $^{23}Na^{40}K$ molecules in their rovibronic and hyperfine ground state. By applying microwaves, we drive coherent Rabi oscillations of spinpolarized molecules between the rotational ground state (J=0) and J=1. The control afforded by microwave manipulation allows us to pursue engineered dipolar interactions via microwave dressing. By driving a twophoton transition, we are also able to observe Ramsey fringes between different J=0 hyperfine states, with coherence times as long as 0.5s. The realization of long coherence times between different molecular states is crucial for applications in quantum information processing. [Preview Abstract] 

D1.00141: Realizing Parafermions in Optical Lattices Fangli Liu, Alexey Gorshkov Parafermions, which are the fractional versions of Majorana fermions, possess more exotic braiding statistics than Majorana fermions and are therefore more powerful from the point of view of topological quantum computing. We propose a scheme to realize parafermionic zero modes in optical lattices, without the use of superconductive paring. With the help of laser assisted tunneling and onsite interactions, two layers of ultracold atoms in distinct hyperfine states can be engineered to host $\pm 1/m $ fractional quantum Hall states. We then introduce a finiteextent potential barrier that pierces both layers  this gives rise to two counterpropagating edge states that sit on top of each other. Finally, laser induced coupling is used to introduce backscattering between the two edge states and to gap them out. We show that the resulting defects give rise to the topological degeneracy associated with parafermions. We also discuss methods for preparation and detection. [Preview Abstract] 

D1.00142: Resonances in the reaction ortho and paraD$_2$ + H at temperatures below 10 K I. Simbotin, R. C\^ot\'e In a previous study [Simbotin and C\^ot\'e, New J. Phys. {\bf 17}, 065003 (2015)] we reported cross sections for the reaction H$_2$ + D in the temperature regime $10^{6} < T < 10$ K, and found pronounced shape resonances, especially in the $p$ and $d$ partial waves. We found that the resonant structures were sensitive to the initial rovibrational state of H$_2$; in particular, we showed that the effect of the nuclearspin symmetry was very important, since ortho and paraH$_2$ gave significantly different results. We now investigate the reaction D$_2$ + H for vibrationally excited ortho and paraD$_2$, and compare and contrast these results with those for H$_2$ + D. We remark that this benchmark system is a prototypical example of reactions with a strong barrier, which have very small cross sections in the cold and ultracold regimes. However, shape resonances can enhance the reaction cross sections by orders of magnitude for temperatures around and below $T=1$ K. Moreover, resonant features would provide stringent tests for quantum chemistry calculations of potential energy surfaces. [Preview Abstract] 

D1.00143: Laser cooling and trapping of YO Shiqian Ding, Alejandra Collopy, Yewei Wu, Eunmi Chae, Aakash Ravi, Loic Anderegg, Benjamin Augenbraun, John Doyle, Jun Ye Using microwave mixing of rotational states and only two vibrational repump lasers, we implement a cycling transition in the yttrium (II) monoxide (YO) molecule that is closed to the 10$^6$ level. With this cycling transition, a beam of YO from a twostage cryogenic buffer gas cell is decelerated by the slowing lasers with broadband modulation and frequency chirping. The resulting decelerated molecules (less than 10 m/s) are slow enough to be loaded into a magnetooptical trap. We present progress towards loading into our radio frequency (5 MHz) MOT. [Preview Abstract] 

D1.00144: Towards an ACMOT of CaF Loic Anderegg, Eunmi Chae, Aakash Ravi, Benjamin Augenbraun, Boerge Hemmerling, Garrett Drayna, Nicholas Hutzler, Alejandra Collopy, Yewei Wu, Shiqian Ding, Jun Ye, Wolfgang Ketterle, John Doyle Ultracold diatomic molecules have rich prospects as candidates to study controlled ultracold chemistry, strongly correlated systems and precision measurements. They are also considered as possible qubits in quantum computing and simulation schemes. We report on progress towards loading CaF into a molecular magnetooptical trap (MOT). An ACMOT will be used to actively remix magnetic dark states via both polarization and magnetic field switching. In order to load a molecular MOT, we have successfully laser slowed a CaF beam to near the expected capture velocity. We describe our ACMOT apparatus, which is designed to cotrap CaF and Li. We outline our planned study of CaFLi collisions to explore the feasibility of sympathetically cooling molecules to ultracold temperatures. [Preview Abstract] 

D1.00145: Effects of Hyperfine Mixing of Rydbergground molecular potentials in Rb Jamie MacLennan, Andira Ramos, Nithiwadee Thaicharoen, Georg Raithel Rydberg molecules formed by the scattering between a groundstate atom and a Rydberg electron can offer new insight into the nature of atomic interactions and molecular structure. Shallow bound states that arise from hyperfineinduced mixing of singlet and triplet channels have recently been predicted [1] and observed for Pstates in Cs [2] and Sstates in $^{87}$Rb [3]. Here we present progress toward characterizing Rb (nD + 5S$_{1/2}$) molecules, including a comparison of the hyperfinemixing effects between the two isotopes ($^{85}$Rb and $^{87}$Rb). \\[4pt] [1] D. A. Anderson, S. A. Miller, and G. Raithel, Phys. Rev. A \textbf{90}, 062518 (2014). \\[0pt] [2] H. Sassmannshausen, F. Merkt, and J. Deiglmayr, Phys. Rev. Lett. \textbf{114}, 133201 (2015). \\[0pt] [3] F. B\"{o}ttcher \textit{et al.}, arXiv:1510.01097v1 (2015). [Preview Abstract] 

D1.00146: Hyperfine structures of the 2 $^{\mathrm{3}}\Pi (\Omega =$1), 2 $^{\mathrm{1}}\Pi (\Omega =$1), and 3 $^{\mathrm{3}}\Sigma ^{\mathrm{+}}(\Omega =$1) states of ultracold$^{\mathrm{\thinspace 85}}$Rb$^{\mathrm{133}}$Cs via short range photoassociation JinTae Kim, Toshihiko Shimasaki, David DeMille We have observed new shortrange photoassociation (PA) to the 2~$^{\mathrm{3}}\Pi (\Omega =$1), 2 $^{\mathrm{1}}\Pi (\Omega =$1), and 3~$^{\mathrm{3}}\Sigma^{\mathrm{+~}}(\Omega =$1) states of ultracold $^{\mathrm{85}}$Rb$^{\mathrm{133}}$Cs molecule, starting with $^{\mathrm{85}}$Rb and $^{\mathrm{133}}$Cs atoms trapped in their \textbar F$_{\mathrm{Rb}}=$2\textgreater and \textbar F$_{\mathrm{Cs}}=$3\textgreater hyperfine states in dark SPOT MOTs We have completed vibrational and electronic assignments of those PA states in the perturbed region where assignments were difficult due to strong mixing between electronic states through spinorbit interaction [1] Further, highresolution (\textasciitilde 10 MHz) PA spectroscopy has revealed rich hyperfine structures in the low $J$, which we can understand using various coupling schemes (Hund's case~$b_{\beta S}$ or Hund's case $b_{\beta J})$ mainly considering Fermi contact interaction. Similarly, we have also observed PA lines in the strongly perturbed singlet (1~$^{\mathrm{1}}\Pi )$ and triplet (2~$^{\mathrm{3}}\Sigma ^{\mathrm{+}})$ states, which also show similar hyperfine structures. Further, we have observed production of RbCs molecules in the rovibronic ground state through these PA lines via onephoton decay, which opens up the possibility of using these new PA lines as an efficient direct path to the rovibronic ground state. [1] Y. Lee \textit{et al}. J. Phys. Chem. A \textbf{112}, 7214 (2008) [Preview Abstract] 

D1.00147: Toward Triplet Ground State NaLi Molecules Sepehr Ebadi, Alan Jamison, Timur Rvachov, Li Jing, Hyungmok Son, Yijun Jiang, Martin Zwierlein, Wolfgang Ketterle The NaLi molecule is expected to have a long lifetime in the triplet groundstate due to its fermionic nature, large rotational constant, and weak spinorbit coupling. The triplet state has both electric and magnetic dipole moments, affording unique opportunities in quantum simulation and ultracold chemistry. We have mapped the excited state NaLi triplet potential by means of photoassociation spectroscopy. We report on this and our further progress toward the creation of the triplet groundstate molecules using STIRAP. [Preview Abstract] 

D1.00148: SPINOR GASES AND MAGNETIC PHENOMENA 

D1.00149: Exact manybody ground states of a spin1 Bose gas in TonksGirardeau limit HsiangHua Jen, Sungkit Yip We investigate the manybody ground states of a onedimensional spin1 Bose gas in TonksGirardeau (TG) limit. It is known that in TG gas limit of scalar bosons, the system becomes fermionized that bosons do not penetrate each other, and their wavefunctions take the form of noninteracting fermions. For a spin1 Bose gas with an infinite atomatom interaction in a harmonic trap, we construct the manybody ground states from the ones of a noninteracting Fermi gas along with the spin degrees of freedom. With zero magnetic field in the sector of $S_z$ $=$ $0$ and in the regime of spinincoherent Luttinger liquid where we assume negligible $a_2  a_0$, the interaction energy becomes spinindependent, and the manybody wavefunctions of a spin1 Bose gas is also SU(3) invariant. The manybody wavefunction can be derived by calculating the weightings of spin functions using the conjugacy class $G$ of $S_N$ symmetric group for the number of atoms $N$. We then study the firstorder correlation function of the density matrix, from which we extract its momentum distribution. Finitetemperature calculation of the wavefunction by including orbital excitations is also investigated to compare with the case of spinless bosons. [Preview Abstract] 

D1.00150: Quantum Spin Liquid in Herbertsmithite Miron Amusia, Vasily Shaginyan We present a theory of herbertsmithite as a quantum spin liquid (QSL) made of chargeless fermionic spinons [1]. The essence of our theory is the notion of socalled fermion condensation quantum phase transition. Main manifestation of it is unlimited increase of the quasiparticles effective mass. We analyze the dynamic magnetic susceptibility of QSL compounds, and show that spinons form a continuum, and populate an approximately flat band crossing the Fermi level. Transport properties of QSL compounds shed light on their nature. We demonstrate that the thermal transport exhibits a scaling behavior, resembling that of heavyfermion compounds, and reveal a strong magnetic field dependence of the effective mass. We propose the arrangement of the thermal transport measurements in magnetic field that could probe the lowlying elementary excitations, testing itinerant spinons excitations in Herbertsmithite. 1. M.Ya. Amusia, K.G. Popov, V.R. Shaginyan, and V. A. Stephanowich, \textit{Theory of HeavyFermion Compounds}, Springer Series in SolidState Sciences \textbf{182,} (2014). . [Preview Abstract] 

D1.00151: Magnons in a box: Condensation and Application Fang Fang, Ryan Olf, Shun Wu, Holger Kadau, G.Edward Marti, Dan StamperKurn Ultracold gases offer us a remarkable window into the quantum world, allowing direct access to a wide range of manybody and condensed matter phenomena at convenient macroscopic length and time scales. However, producing ultracold gases at ever lower entropy, and measuring statistical properties such as temperature in these low entropy regimes, is a persistent challenge. Magnons, gapless spin excitations of spinor Bose Einstein Condensate (BEC), are expected to behave like free particles. We show that magnons can be used to cool BEC in a deep trap and serve as a thermometer to measure temperatures at extremely low entropyperparticle. Unlike atoms trapped in a harmonic trap, trapped magnons experience a box potential due to near exact cancellation of the trapping potential by the meanfield interaction within the condensate. We observe the quasicondensation of magnon excitations within this naturemade box. [Preview Abstract] 

D1.00152: Apparatus to study matterwave quantum optics in spin space in a sodium spinor BoseEinstein condensate Delaram Nematollahi, Qimin Zhang, Joseph Altermatt, Shan Zhong, Matthew Goodman, Anita Bhagat, Arne Schwettmann We present our apparatus designed to study matterwave quantum optics in spin space, including our recently finished vacuum system and laser systems. Microwavedressed spinexchange collisions in a sodium spinor BoseEinstein condensate provide a precisely controllable nonlinear interaction that generates squeezing and acts as a source of entanglement. As a consequence of this entanglement between atoms with magnetic quantum numbers m=+1 and m=1, the noise of population measurements can be reduced below the shot noise. Versatile microwave pulse sequences will be used to implement an interferometer, a phasesensitive amplifier and other devices. With an added ion detector to detect Rydberg atoms via pulsedfield ionization, we plan to study the effect of Rydberg excitations on the spin evolution of the ultracold gas. [Preview Abstract] 

D1.00153: Collisional spin evolution in microwavedressed F=1 spinor BoseEinstein condensates Qimin Zhang, Delaram Nematollahi, Arne Schwettmann, Eite Tiesinga Spinexchange collisions in F=1 spinor BoseEinstein condensates, where two atoms with magnetic quantum number m=0 collide and change into a pair with m=+/1, are useful to implement matterwave quantum optics in spin space, because the collisions generate entanglement and they can be precisely controlled using microwave dressing. Here, we numerically investigate the collisional evolution of spin populations in a single spatial mode for different initial superposition states and applied microwave pulse sequences. To find the parameter regime where quantum effects dominate, we compare results from our fully quantum simulation involving a large basis set to those obtained from a semiclassical model based on quasiprobability distributions. Our simulations are motivated by our planned experiments on matterwave quantum optics in this system, including the creation and characterization of twomode squeezing between the m=+/1 spin projections as well as the construction of a nonlinear spinexchange based interferometer to measure phase with uncertainties that improve upon the shotnoise limit in the number of atoms in the m=+/1 states. [Preview Abstract] 

D1.00154: The ground state of a spin1 antiferromagnetic atomic condensate for Heisenberg limited metrology LingNa Wu, Li You The ground state of a spin1 atomic condensate with antiferromagnetic interaction can be applied to quantum metrology approaching the Heisenberg limit. Unlike a ferromagnetic condensate state where individual atomic spins are aligned in the same direction, atoms in an antiferromagnetic ground state condensate exist as spin singlet pairs, whose inherent correlation promises metrological precisions beyond the standard quantum limit (SQL) for uncorrelated atoms. The degree of improvement over the SQL is measured by quantum Fisher information (QFI), whose dependence on the ratio of linear Zeeman shift $p$ to spindependent atomic interaction $c$ is studied. At a typical value of $p=0.4c$ corresponding to a magnetic field of $28.6\,\ \mu$G with $c=h \times 50$\,Hz (for $^{23}$Na atom condensate in the $F=1$ state at a typical density of $\sim 10^{14}{\rm{cm}}^{3}$), the scaled QFI can reach $\sim 0.48 N$, which is close to the limits of $N$ for NooN state, or $0.5N$ for twinFock state. We hope our work will stimulate experimental efforts towards reaching the antiferromagnetic condensate ground state at extremely low magnetic fields. [Preview Abstract] 

D1.00155: Characterizing the nature of superfluid to Mottinsulator transitions via microwave spectroscopy Lichao Zhao, Zihe Chen, Tao Tang, Yingmei Liu Superfluid to Mottinsulator quantum phase transitions can be first order or second order in a spin1 sodium spinor BoseEinstein condensate confined by a threedimensional optical lattice. This is mainly due to the antiferromagnetic nature of spindependent interactions in the sodium system. We experimentally demonstrate that the nature of the phase transitions in spinor condensates can be characterized via microwave spectroscopy in a quantum quench scenario. A comparison between our observations and the meanfield theory is also discussed. [Preview Abstract] 

D1.00156: A Geometric Description of Raman Fingerprints on Spinor BECs Justin T. Schultz, Azure Hansen, Joseph D. Murphree, Maitreyi Jayaseelan, Nicholas P. Bigelow We employ a geometric description of a coherent, diabatic twophoton Raman interaction as a rotation on the Bloch sphere of a spin1/2 system. The spin state of the system is described by a point on the sphere and the time evolution is described by a trajectory of the sphere’s surface. The axis of rotation is determined by properties of the optical Raman beams: the pulse area, the relative intensities, relative phase, and relative frequencies. The twophoton detuning gives fine control over the sizes and phases of the imprinted features. This interpretation allows us not only to precisely engineer complex, spatially varying spin textures, but also to characterize these textures with a form of atomic polarimetry as we demonstrate on a coreless vortex in a spinor BEC. [Preview Abstract] 

D1.00157: Control of spinor dynamics in an antiferromagnetic F=1 BoseEinstein condensate Zachary Glassman, Donald Fahey, Ryan Wilson, Eite Tiesinga, Paul Lett Spinexchange collisions driving coherent population oscillations of the $F=1$ ground state magnetic sublevels can be used for precision quantum measurements in a condensed Bose gas. Entanglement generated by these dynamics enables below standard quantum limit phase estimation by way of an SU(1,1) interferometer and antiferromagnetic spinnematic squeezing. In order to observe these effects, we have simulated the spinor dynamics in the single mode approximation with both fully quantum and semiclassical models. We present a study of microwave pulse sequences, which can be used to control the spinor dynamics via energy level shifts and rotations, and discuss improved methods for future experiments in this field. [Preview Abstract] 

D1.00158: QUANTUM GASES IN LOW DIMENSIONS 

D1.00159: ManyBody Simulations of Ultracold 1D AtomIon Quantum Systems Johannes M. Schurer, Antonio Negretti, Rene Gerritsma, Peter Schmelcher We consider a atomion hybrid system consisting of an ultracold bosonic atom cloud and a single ion. The polarization interaction between the atoms and the ion scales like $1/r^4$ and is therefore longrange and attractive featuring bound states. Hence, this interaction induced an additional length and energy scale to the system and is expected to trigger the formation of density bubbles [1] or large molecular ions [2]. We investigated the influence of this interaction on the groundstate [3] as well as the dynamical [4] properties of the atomic ensemble for various intraatomic interactions and particle numbers. Furthermore, we show that the atomion scattering properties can be exploited to switch the dynamics of a bosonic Josephson junction by an ionic impurity in the weak link [5]. Our study is carried out by means of the multiconfiguration timedependent Hartree method for bosons [6], a numerical exact and ab initio method to calculate manybody quantum dynamics. \newline [1] Goold et al, PRA 81, 041601 (2010) [2] C\^{o}t\'e et al, Lett. 89, 093001 (2002) [3] Schurer et al, PRA 90, 033601 (2014) [4] Schurer et al, NJP 17 083024 (2015) [5] Schurer et al, arXiv:1511.00977 [6] Alon et al, PRA 77, 033613 (2008) [Preview Abstract] 

D1.00160: Threebody recombination in a quasitwodimensional quantum gas Bo Huang, Alessandro Zenesini, Rudolf Grimm Quantum threebody recombination in threedimensional systems is influenced by a series of weakly bound trimers known as Efimov states, which are induced by shortrange interactions and exhibit a discrete scaling symmetry. On the other hand, twodimensional systems with contact interactions are characterized by continuous scale invariance and support no Efimov physics. This raises questions about the behaviour of threebody recombination in the transition from three to two dimensions. We use ultracold caesium atoms trapped in anisotropic potentials formed by a pair of counterpropagating laser beams to experimentally investigate threebody recombination in quasitwodimensional systems with tunable confinement and tunable interactions. In our recent experiments, we observed a smooth transition of the threebody recombination rate coefficient from a threedimensional to a deeply quasitwodimensional system. A comparison between the results obtained near two Feshbach resonances indicates a universal behaviour of threebody recombination in the quasitwodimensional regime. [Preview Abstract] 

D1.00161: Measuring SpinCharge Separation in a 1D Fermi Gas Jacob A. Fry, Melissa C. Revelle, Randall G. Hulet We present progress on measurement of spincharge separation in a twocomponent, strongly interacting, 1D gas of fermionic lithium. A characteristic feature of interacting 1D Fermi gases is that the velocity of a charge excitation propagates faster than a spin excitation. We create an excitation by applying a dipole force at the center of the cloud using a sheet of light. Depending on the detuning of this beam, we can either excite both spin species equally (charge excitation) or preferentially (spin excitation)\footnote{A. Recati, P. O. Fedichev, W. Zwerger, and P. Zoller, \textbf{Phys. Rev. Lett.} 90, 020401 (2003).}. Once this beam is turned off, the excitations propagate to the edges of the atomic cloud at a velocity determined by coupling strength. A magnetically tuned Feshbach resonance enables us to vary this coupling and map out the velocities of spin and charge excitations. [Preview Abstract] 

D1.00162: Selforganization of atoms coupled to a chiral reservoir Zachary Eldredge, Christopher Jarzynski, Darrick Chang, Alexey Gorshkov Tightly confined modes of light, as in optical nanofibers or photonics crystal waveguides, can lead to large optical coupling in atomic systems, which mediates longrange interactions between atoms. These onedimensional systems can naturally possess couplings which are asymmetric between modes in different directions. In this poster, we examine the selforganizing behavior of atoms in one dimension coupled to a chiral reservoir. We determine the behavior of the selforganized solution to the equations of motion in different parameter regimes, relative to both the detuning of the pump laser and the degree of reservoir chirality. In addition to the spatial configuration of selforganized atoms, we calculate possible experimental signatures. [Preview Abstract] 

D1.00163: Detecting different correlation regimes in a 1D Bose gas using insitu absorption imaging Francisco SalcesCarcoba, Seiji Sugawa, Yuchen Yue, Andika Putra, Ian Spielman We present the realization of a single 1D Bose gas (1DBG) using a tightly focused LaguerreGauss beam as a waveguide for a 87Rb cloud. Axial confinement is provided by a weak trap that also sets the final density profile. A homogeneous 1DBG at T $=$ 0 can be fully described by the dimensionless interaction parameter $\gamma \propto $ 1/n, where n is the linear density; at sufficiently low densities the system becomes strongly interacting. An inhomogeneous (trapped) system can enter this description within the local density approximation (LDA) where the interaction parameter becomes position dependent $\gamma $(x)$\propto $ 1/n(x). The system then displays different correlation regimes over its extension which can be detected by measuring its equation of state (EoS) or the density density correlations in real space using insitu absorption imaging. [Preview Abstract] 

D1.00164: Bound and scattering properties in waveguides around freespace Feshbach resonance Gaoren Wang, Panogiotis Giannakeas, Peter Schmelcher The twobody bound and scattering properties in an onedimensional (1D) harmonic waveguide in the vicinity of freespace magnetic Feshbach resonances are investigated based on the local frame transformation approach. The multichannel characteristics of the interatomic interaction is taken into account. We examine the crossing between the bound state in the waveguide and the ground level of the transverse confinement, i.e. when the bound state crosses the scattering threshold in the waveguide and turns into a continuum state. For swave collision, the crossing occurs at the magnetic field where the effective 1D interaction strength {\$}g\textunderscore \textbraceleft 1D\textbraceright {\$} vanishes, and the effective 1D scattering length {\$}a\textunderscore \textbraceleft 1D\textbraceright {\$} diverges. This observation indicates that the molecular formation or atom loss signal in a harmonic waveguide is expected at the magnetic field where {\$}a\textunderscore \textbraceleft 1D\textbraceright {\$} is infinite. Molecule formation is absent at position of the confinement induced resonance which is characterized by the divergence of {\$}g\textunderscore \textbraceleft 1D\textbraceright {\$}. [Preview Abstract] 

D1.00165: Connections between fermions and bosons that rotate in two dimensional harmonic traps Bin Yan, Rachel Wooten, Chris Greene The quantum Hall effect (QHE) was originally observed in twodimensional electron materials in strong perpendicular magnetic fields. Theoretical treatments suggest that the QHE should also be observable in an analogous twodimensional bosonic gas. In recent years, there has been significant interest in studying the QHE and its bosonic analog in highlycontrolled atomic systems. While fermions and bosons have fundamentally different behavior, there is a connection between bosons and fermions in the presence of strong interactions. In the lowest Landau level (the strong magnetic field limit), the Hilbert subspace of N fermions with a specific total relative angular momentum, M, is isomorphic to the Hilbert subspace of N bosons with a different M. However, even though these Hilbert subspaces are isomorphic, in the presence of Coulomb repulsion their energy spectra exhibit intriguing similarities. This study solves the boson and fermion problems in their corresponding Hilbert spaces, and compares their energy level statistics, as well as the connection between their ground state wave functions. [Preview Abstract] 

D1.00166: Fewboson processes in the presence of an attractive impurity under onedimensional confinement Nirav Mehta, Connor Morehead We consider the universal fewbody physics of a single light impurity atom $(L)$ interacting with a few heavier atoms $(H)$ under strict onedimensional confinement with zerorange interactions. Due to the mass imbalance, the system is nonintegrable. All universal properties are specified by the mass ratio $\beta = m_L/m_H$ and the coupling ratio $\lambda = g_{HH}/g_{HL}$, enabling the calculation of fewbody ``phase diagrams'' on the $\lambda$$\beta$ plane. Because the threebody and fourbody eigenenergies determine the energy thresholds for inelastic scattering processes involving $HL$, $HHL$ and $HHHL$ collision partners, we are able to partition the $\lambda$$\beta$ phase space into regions according to whether or not particular inelastic processes are energetically allowed. [Preview Abstract] 

D1.00167: Nonequilibrium dynamics of an ensemble of 2D Fermi gases Haille Sharum, Scott Smale, Christopher Luciuk, Stefan Trotzky, Tilman Enss, Zhenhua Yu, Shizhong Zhang, Joseph Thywissen We study the dynamics of an ensemble of two dimensional Fermi gases near Feshbach scattering resonances. We begin our experiments with a weakly interacting or noninteracting gas and initiate strong interactions on a timescale that is fast compared to equilibration. We probe the evolution of the shortranged part of the manybody wavefunction via radio frequency spectroscopy. Alternatively, we perform spin echo measurements to reveal the dissipative (spin diffusion) and reactive (LeggettRice effect) components of transverse spin currents. [Preview Abstract] 

D1.00168: Pair condensation in a spinimbalanced twodimensional Fermi gas Peter Brown, Debayan Mitra, Peter Schauss, Stanimir Kondov, Waseem Bakr We study the phase diagram of the stronglyinteracting spinimbalanced Fermi gas in two dimensions, where the low dimensionality enhances correlations and phase fluctuations. Our interest is motivated by the connection of this system with superconductivity in the presence of a large Zeeman field. We observe pair condensation for a range of spin imbalance and interaction strengths. The measurement of the phase diagram opens the door for a detailed investigation of exotic phases such as the Sarma/broken pair phase and the elusive FFLO phase. [Preview Abstract] 

D1.00169: ATOMIC CLOCKS 

D1.00170: Gravitational wave detection with optical lattice clocks Shimon Kolkowitz, Nick Langellier, Igor Pikovski, Mikhail Lukin, Ron Walsworth, Jun Ye We discuss the prospects for using optical lattice clocks for gravitational wave detection. We compare a spacebased clock detector to other existing and proposed techniques, and analyze its potential for detecting lowfrequency gravitational waves. [Preview Abstract] 

D1.00171: Progress with a green astrocomb for exoplanet searches. Type: poster. David F. Phillips, ChihHao Li, Alexander Glenday, Dimitar Sasselov, Andrew Szentgyorgyi, Ronald L. Walsworth Searches for extrasolar planets using the precision stellar radial velocity (RV) measurement technique are approaching Earthlike planet sensitivity. Astrocombs, which consist of a laser frequency comb, coherent wavelength shifting mechanism (such as a doubling crystal and photonic crystal fiber), and a modefiltering FabryPerot cavity (FPC), provide a promising route to increased accuracy and longterm stability on the astrophysical spectrograph calibration. We first present the design of a green astrocomb from an octave spanning Ti:Sapphire laser, spectrally broadened by custom tapered PCF to the visible band via fiberoptic Cherenkov radiation for frequency shifting, and filtered by a broadband FPC, constructed by a pair of complementary chirped mirrors. We also present results from three years of operation of the astrocomb calibrating the HARPSN spectrograph at the Italian National Telescope on La Palma, Canary Islands, including its use in measurements of solar radial velocities as well as its use in searches for extrasolar planets. [Preview Abstract] 

D1.00172: Characterization of the Oxidation State of $^{\mathrm{229}}$Th Recoils Implanted in MgF$_{\mathrm{2}}$ for the Search of the Lowlying $^{\mathrm{229}}$Th Isomeric State Beau Barker, Edmund Meyer, Mike Schacht, Lee Collins, Marianne Wilkerson, XinXin Zhao The lowlying (7.8 eV) isomeric state in $^{\mathrm{229}}$Th has the potential to become a nuclear frequency standard. $^{\mathrm{229}}$Th recoils from $^{\mathrm{233}}$U decays have been collected in MgF$_{\mathrm{2}}$ for use in the direct search of the transition. Of interest is the oxidation state of the implanted $^{\mathrm{229}}$Th atoms as this can have an influence on the decay mechanisms and photon emission rate. Too determine the oxidation state of the implanted $^{\mathrm{229}}$Th recoils we have employed laser induced florescence (LIF), and planwave pseudopotential DFT calculations to search for emission from thorium ions in oxidation states less than $+$4. Our search focused on detecting emission from Th$^{\mathrm{3+}}$ ions. The DFT calculations predicted the Th$^{\mathrm{3+}}$ state to be the most likely to be present in the crystal after Th$^{\mathrm{4+}}$. We also calculated the band structure for the Th$^{\mathrm{3+}}$ doped MgF$_{\mathrm{2}}$ crystal. For LIF spectra a number of excitation wavelengths were employed, emission spectra in the visible to nearIR were recorded along with timeresolved emission spectra. We have found no evidence for Th$^{\mathrm{3+}}$ in the MgF$_{\mathrm{2}}$ plates. We also analyzed the detection limit of our apprentice and found that the minimum number of Th$^{\mathrm{3+}}$ atoms that we could detect is quite small compared to the number of implanted $^{\mathrm{229}}$Th recoils. The number of implanted $^{\mathrm{229}}$Th recoils was derived from a $\gamma $ray spectrum by monitoring emission from the daughters of $^{\mathrm{228}}$Th. These were present in the MgF$_{\mathrm{2}}$ plates due to a $^{\mathrm{232}}$U impurity, which decays to $^{\mathrm{228}}$Th, in the source. LAUR1620442 [Preview Abstract] 

D1.00173: Stability improvements for the NIST Yb optical lattice clock R.J. Fasano, M. Schioppo, W.F. McGrew, R.C. Brown, N. Hinkley, T.H. Yoon, K. Beloy, C.W. Oates, A.D. Ludlow To reach the fundamental limit given by quantum projection noise, optical lattice clocks require advanced laser stabilization techniques. The NIST ytterbium clock has benefited from several generations of extremely high finesse optical cavities, with cavity linewidths below 1 kHz. Characterization of the cavity drift rate has allowed compensation to the mHz/s level, improving the mediumterm stability of the cavity. Based on recent measurements using Ramsey spectroscopy with synchronous interrogation, we report a fractional instability $\sigma_y(1\textrm{ s})\leq 10^{16}$, dominated by atom number fluctuation noise. We also provide updates on our cryogenic sapphire cavity with a reduced thermal noise floor, which will improve our Dicklimited fractional instability at 1 s to below $10^{16}$. [Preview Abstract] 

D1.00174: Towards a portable optical clock based on a twophoton transition Shreyas Potnis, Shira Jackson, Amar Vutha Optical clocks based on narrow linewidth atomic transitions have achieved an unprecedented level of precision. These clocks rely on tight confinement of atoms by light, to mitigate Doppler shifts and atomic recoil, with the trapping light appropriately tuned to a ``magic'' wavelength to eliminate light shifts. An alternative approach is construct optical clocks using inherently Dopplerfree twophoton transitions, which can lead to a substantially simplified architecture. The short cycle time and large atom numbers available with such a scheme enable rapid, high signaltonoise measurements, paving the way for portable and autonomous clocks. We report on experimental progress towards constructing an optical clock based on the $4s^{2}\,^{1}S_{0}\rightarrow4s3d\,^{1}D_{2}$ twophoton transition in laser cooled $^{40}\mathrm{Ca}$ atoms. [Preview Abstract] 

D1.00175: FUNDAMENTAL CONSTANTS AND TESTS OF BASIC LAWS 

D1.00176: Towards quantum control of molecular ions David Hanneke, Edward Kleiner, Alexander Frenett Many atoms and molecules possess interesting spectroscopic transitions, but lack dissipative transitions useful for control and detection of internal states. In particular, molecules are candidates for quantum memories, lowtemperature chemistry studies, tests of fundamental symmetries, and searches for timevariation of fundamental constants, but most lack a convenient cycling transition. By cotrapping a molecular ion with an atomic ion, the atom can provide all dissipation and detection. We present a system capable of such quantum control and report progress towards its use. We also present candidate molecules with analysis of potentially interesting transitions and systematic effects. [Preview Abstract] 

D1.00177: Search for a coupling of the proton spin to gravity Derek Jackson Kimball, Jordan Dudley, Yan Li, Dilan Patel We present an overview of progress in our search for a longrange coupling between rubidium (Rb) nuclear spins and the mass of the Earth [D. F. Jackson Kimball et al., Annalen der Physik {\textbf{525}}(7), 514–528 (2013)], which can be interpreted as a search for a longrange monopoledipole interaction or a spingravity coupling. The experiment consists of simultaneous measurement of the spin precession frequencies of overlapping ensembles of Rb85 and Rb87 atoms contained within an evacuated, antirelaxationcoated vapor cell. Because of the nuclear structure of Rb85 and Rb87, the experiment is particularly sensitive to anomalous spindependent interactions of the proton [D. F. Jackson Kimball, New J. Phys. {\textbf{17}}, 073008 (2015)]. We have studied a number of important systematic effects related to vector and tensor light shifts, optical pumping effects, the ac and nonlinear Zeeman effects, and magnetic field gradients. We anticipate that our experiment can improve sensitivity to anomalous longrange spinmass couplings of the proton compared to previous experiments by more than an order of magnitude. [Preview Abstract] 

D1.00178: Gravitational Interactions for Dirac Particles and Antiparticles Ulrich D. Jentschura, Jonathan H. Noble The coupling of the Dirac equation to gravity has been a matter of some debate over the last few decades. However, the development of the socalled spinconnection formalism which couples the Dirac particle to a curved spacetime background seems to have settled the question. This formalism implies that it is not permissible in a fully relativistic theory to simply add the gravitational potential into the Dirac equation as one would otherwise add the Coulomb potential. Furthermore, the fact that the Dirac equation describes both particles and antiparticles simultaneously is sometimes underappreciated by the community. In a series of recent papers [Phys. Rev. A 87 (2013) 032101; Phys. Rev. A 88 (2013) 022121; Phys Rev A 90 (2014) 022112; Phys. Rev. A 91 (2015) 022112; Phys. Rev. A 92 (2015) 012101], related questions have been studied in detail. A symmetry relation has been established for the interactions of particles versus antiparticles in relation to their gravitational interactions, firmly establishing the equivalence principle for antiparticles in the sense that if the mass term in the Dirac equation describes the inertial mass of particles and antiparticles (and they have tested to be equal to good accuracy), then the same. [Preview Abstract] 

D1.00179: Determination of the proton charge radius from elastic electronproton scattering Marko Horbatsch, Eric A. Hessels Precisely measured electronproton elastic scattering cross sections [Phys. Rev. Lett. 105, 242001 (2010)] are reanalyzed to evaluate their strength for determining the rms charge radius ($R_{\rm E}$) of the proton. More than half of the cross sections at lowest $Q^2$ are fit using two singleparameter formfactor models, with the first based on a dipole parametrization, and the second on a linear fit to a conformalmapping variable. These low$Q^2$ fits extrapolate the slope of the form factor to $Q^2 = 0$ and determine $R_{\rm E}$ values of approximately 0.84 and 0.89 fm, respectively. Fits spanning all $Q^2$, in which the single constants are replaced with cubic splines at larger $Q^2$, lead to similar results for $R_{\rm E}$. We conclude that the scattering data are consistent with $R_{\rm E}$ ranging from at least 0.84 to 0.89 fm, and therefore is consistent with both of the discrepant determinations of $R_{\rm E}$ made using muonic and electronic hydrogenatom spectroscopy. Phys. Rev. C 93, 015204 (2016) [Preview Abstract] 

D1.00180: Frequencyoffset separated oscillatory fields: A demonstration of a new technique for a measurement of the helium n=2 triplet P fine structure D. W. Fitzakerley, K. Kato, M. C. George, A. C. Vutha, T. D. G. Skinner, N. Bezginov, E. A. Hessels We perform a proofofprinciple demonstration of the frequencyoffset separated oscillatory field (FOSOF) technique [Phys. Rev. A 92,052504 (2015)]. For the FOSOF technique, the two separated field have frequencies which are offset from each other, so that the relative phases of the fields varies linearly in time. This proofofprinciple demonstration measures the $2^3$P$_1$~$m$=1 to $2^3$P$_2$~$m$=1 transition in atomic helium and demonstrates the usefulness of the FOSOF technique for highprecision atomic measurements. [Preview Abstract] 

D1.00181: Progress towards a precision measurement of the n=2 triplet P fine structure of atomic helium K. Kato, D. W. Fitzakerley, M. C. George, A. C. Vutha, C. H. Storry, E. A. Hessels We report progress on the measurement of the $J$=1 to $J$=2 2$^3$P finestructure interval of atomic helium. The measurement uses a liquidnitrogencooled DC discharge source of metastable helium and the atomic beam is laser cooled in the transverse directions. The atoms are excited to 2$^3$P by a 1083nm diode laser, and the finestructure transition is driven by microwaves using the frequencyoffset separated oscillatory fields technique [Phys. Rev. A 92, 052504 (2015)]. The transition is detected by further laser excitation to a Rydberg state, followed by Stark ionization. [Preview Abstract] 

D1.00182: A tabulation of the boundstate energies of atomic hydrogen E.A. Hessels, M. Horbatsch We present tables for the boundstate energies for atomic hydrogen which include the hyperfine structure [1], and thus this work extends the work of Rev. Mod. Phys. 84, 1527 (2012). The tabulation includes corrections of the hyperfine structure due to the anomalous moment of the electron, due to the finite mass of the proton, and due to offdiagonal matrix elements of the hyperfine Hamiltonian. Simple formulas valid for all quantum numbers (not found previously in the literature) are presented for the hyperfine corrections. The tabulated energies have uncertainties of less than 1 kHz for all states. This accuracy is possible because of the recent precision measurement [Nature, 466, 213 (2010); Science, 339, 417 (2013)] of the proton radius. The effect of this new radius on the energy levels is also tabulated, and the energies are compared to precision measurements of atomic hydrogen energy intervals. [1] arXiv 1601.01057 [Preview Abstract] 

D1.00183: Association and dissociation of Feshbach molecules in a microgravity environment Jose P D'Incao, Jason R Willians NASA’s Cold Atom Laboratory (CAL) is a multiuser facility scheduled for launch to the ISS in 2017. Our flight experiments with CAL will characterize and mitigate leadingorder systematics in dualatomicspecies atom interferometers in microgravity relevant for future fundamental physics missions in space. Here, we study the RF association and dissociation of weakly bound heteronuclear Feshbach molecules for expected parameters relevant for the microgravity environment of CAL. This includes temperatures on the picoKelvin range and atomic densities as low as $10^8$/cm$^3$. We show that under such conditions, thermal and loss effects can be greatly suppressed, resulting in high efficiency in both association and dissociation of extremely weakly bound Feshbach molecules and allowing for high accuracy determination coherent properties of such processes. Our theoretical model for $^{41}$K$^{87}$Rb mixture includes thermal, loss, and density effects in a simple and conceptually clear manner. We derive several conditions in terms of the temperature, density and scattering lengths, determining the regime in which one can achieve efficient association and dissociation. This research is supported by the National Aeronautics and Space Administration. [Preview Abstract] 

D1.00184: Observations of the $4 \;{}^1\Sigma_u^+$ state of H$_2$ Alexander Chartrand, Robert Ekey, Elizabeth McCormack Resonantlyenhanced multiphoton ionization via the $EF\;{}^1\Sigma_g^+$, $v'=6$ doublewell state has been used to probe the energy region of the high vibrational levels of the $4\;{}^1\Sigma_u^+$ state of H$_2.$ Theoretical {\it ab initio} potential energy curves\footnote{G. Staszewska and L. Wolniewicz, {\it J. Mol. Spectrosc.} {\bf 212}, 208212 (2002)} for this state predict a deep innerwell and shallow outer well due to an avoided crossing with the $B''\bar{B} \;^1\Sigma_u^+$ curve. Transitions to the $4\;^1\Sigma_u^+$ state have not been assigned previously because absorption from the $(1s\sigma)^2$ ground state is forbidden due to the $f$ character of the inner well. However, transitions from the $EF\;^1\Sigma_g^+$ state with inner well $s$ character and combined doublyexcited and $d$ character outer well are allowed. The high vibrational levels converging on the third dissociation limit should exhibit rotational constant values dependent on the varying amounts of inner and outerwell character for a given $v$. We report experimental energies for the $v=812$ levels and compare favorably to the predicted adiabatic rovibrational energies$^1$. The $v=9$ level is the exception since it lies just above the avoided crossing, which makes predicting its energy difficult. [Preview Abstract] 

D1.00185: Sexual Harassment Reported Among a Sample of Undergraduate Women in Physics Lauren M. Aycock, Eric Brewe, Kathryn B. H. Clancy, Renee Michelle Goertzen, Zarha Hazari, Theodore Hodapp The field of physics lags behind most other scientific fields in gender parity of students earning bachelor's degrees. The transition from enrollment in high school physics to graduating with physics degree represents the biggest decrease in the proportion of female students for any step in physics educational attainment. Sexual harassment contributes to an unwelcome climate. It is unknown how prevalent sexual harassment is in the field of physics and whether it's a contributing factor to the field's inability to recruit and retain female students. Our goal was to measure a quantitative baseline for sexual harassmentassociated with physicsobserved and experienced by a sample of female undergraduate students. As part of a larger conference evaluation survey, we conducted an internetbased survey (n$=$632) of attendees of the APS Conference for Undergraduate Women in Physics to measure the extent to which they personally experienced or observed sexual harassment in a context associated with physics. We will present results from this survey. Opinions, findings, or conclusions expressed in this work do not necessarily reflect the views of the NSF, DOE, or APS. [Preview Abstract] 

D1.00186: Radiative and rovibrational collisional relaxation of sodium dimer Burcin Bayram, Tim Horton, Jacob McFarland Radiative and rovibrational collisional relaxation of sodium dimer of the A$^{\mathrm{1}}\Sigma^{\mathrm{+}}_{\mathrm{u}}$ (8,30) state have been measured by direct observation of the decay fluorescence. Sodium molecular vapor is created in a heatpipe oven at 600 K and excited using a 6ns pulsed dye laser pumped by a Nd:YAG, operating at 532 nm. The preliminary lifetime measurement was done by directly acquiring lifetime data through boxcar averager from the stored oscilloscope trace of the fluorescence. Analysis of the exponential decay of the fluorescence allows us to obtain the radiative lifetime. By introducing the argon buffer gas and varying the pressure of the heatpipe, a collisional cross section between excited sodium dimer and ground state argon atom collision can be extracted using SternVolmer relation. [Preview Abstract] 

D1.00187: Light assisted collisions in ultra cold Tm atom Alexey Akimov, Ivan Cojocaru, Sergey Pyatchenkov, Stepan Snigirev, Ilia Luchnokov, Denis Sukachev, Elena Kalganova, Vadim Sorokin Recently laser cooled rare earth elements attracted considerable attention due to the high orbital and magnetic moments. Such a systems allow lowfield Feshabach resonances enabling tunable in wide range interactions. In particular, thulium atom has one hole in 4f shell therefore having orbital moment of 3 in the ground state, magnetic moment of 4 Bohr magnetons in ground state. While magnetic moment of the thulium atom is less than that of Erbium or Dysprosium simpler level structure, possibility to capture thulium atoms and the dipole trap at 532~nm make thulium atom an extremely attractive subject for quantum simulations. Nevertheless collisional properties of thulium atom are not yet explored in details, in particular light assisted collision of thulium atom were not yet investigated. In this contribution, we performed studies of light assisted collisions near in Magneto optical trap operating on narrow 530.7 nm transition. We found, that light assisted inelastic binary collisions losses rate is around $\beta \sim 10^{9}{\mbox{cm}^{\mbox{3}}} \mathord{\left/ {\vphantom {{\mbox{cm}^{\mbox{3}}} {\mbox{s}}}} \right. \kern\nulldelimiterspace} {\mbox{s}}$. Possible mechanism of losses from the trap are discussed [Preview Abstract] 

D1.00188: Complex Kohn calculations on an overset grid Loren Greenman, Robert Lucchese, C. William McCurdy An implentation of the overset grid method for complex Kohn scattering calculations is presented, along with static exchange calculations of electronmolecule scattering for small molecules including methane. The overset grid method uses multiple numerical grids, for instance Finite Element Method  Discrete Variable Representation (FEMDVR) grids, expanded radially around multiple centers (corresponding to the individual atoms in each molecule as well as the centerofmass of the molecule). The use of this flexible grid allows the complex angular dependence of the wavefunctions near the atomic centers to be welldescribed, but also allows scattering wavefunctions that oscillate rapidly at large distances to be accurately represented. Additionally, due to the use of multiple grids (and also grid shells), the method is easily parallelizable. The method has been implemented in ePolyscat, a multipurpose suite of programs for general molecular scattering calculations. It is interfaced with a number of quantum chemistry programs (including MolPro, Gaussian, GAMESS, and Columbus), from which it can read molecular orbitals and wavefunctions obtained using standard computational chemistry methods. The preliminary static exchange calculations serve as a test of the applicability [Preview Abstract] 

D1.00189: Electron capture by bare ions on water molecules Roberto Rivarola, Pablo Montenegro, Juan Monti, Omar Foj\'on Single electron capture from water molecules by impact of bare ions is theoretically investigated at intermediate and high collision energies. This reaction is of fundamental importance to determine the deposition of energy in biological matter irradiated with ion beams (hadrontherapy), dominating other ionizing processes of the target at lowintermediate impact velocities and giving principal contributions to the energetic region where electronic stopping power maximizes. The dynamics of the interaction between the aggregates is described within the one activeelectron continuum distorted wave–eikonal initial state theory. The orbitals of the target in the ground state are represented using the approximate selfconsistent complete neglect of differential orbitals (SCCNDO) model. The contribution of different molecular orbitals on the partial cross sections to selected nprincipal quantum number projectile states is discriminated as well as the collaboration of these nstates on total cross sections. The latter ones are dominated by capture to n=1 states at high enough energies decreasing their contribution as n increases. [Preview Abstract] 

D1.00190: Dynamics of Bloch State Positronium Emission from MOF Targets Studied via Rydberg TOF Spectroscopy Alina Pi\~{n}eiro Escalera, Adric Jones, Allen Mills Recent advances in the efficient production\footnote{\small D. B. Cassidy, et. al., Phys. Rev. Lett. {\bf 108}, 043401 (2012).} and detection\footnote{\small A. C. L. Jones, et. al., Phys. Rev. Lett. {\bf 114}, 153201 (2015).} of Rydberg positronium (Ps) have made it possible to perform energy and angle resolved timeofflight (TOF) spectroscopy with Ps. We report here TOF measurements of Ps emission from the metaloxide framework (MOF) targets, MOF5 and ZIF8. MOFs are a recently synthesized\footnote{\small H. Li, et. al., Nature {\bf 402}, 276 (1999).} class of chemical structures, characterized by high longrange order and large surface area to volume ratios (i.e., they are highly porous and uniform, crystalline materials). Ps is found to be emitted predominantly in a series of monoenergetic peaks, providing clear evidence of Ps Bloch states. Measuring the relative populations of the monoenergetic peaks, as a function of implantation energy and target temperature, provides insight into the targetdependent dynamics of Bloch state Ps. [Preview Abstract] 

D1.00191: Prominent conjugate processes in the PCI recapture of photoelectrons revealed by high resolution Auger electron measurements of Xe Yoshiro Azuma, Satoshi Kosugi, Norihiro Suzuki, Eiji Shigemasa, Hiroshi Iwayama, Fumihiro Koike The Xe ($N_{\mathrm{5}}O_{\mathrm{2,3}}O_{\mathrm{2,3}})$ Auger electron spectrum originating from 4$d^{\mathrm{1}}_{\mathrm{5/2}}$ photoionization was measured with the photon energy tuned very close above the ionization threshold. As the photon energy approached the 4$d^{\mathrm{1}}_{\mathrm{5/2}}$ photoionization threshold, Rydberg series structures including several angular momentum components were formed within the Auger profile by the recapture of the photoelectrons into highlying final ion orbitals. Our spectrum with resolution much narrower than the lifetime width of the corresponding core excited state allowed us to resolve detailed structures due to the orbital angular momenta very clearly. Unexpectedly, conjugate peaks originating from the exchange of angular momentum between the photoelectron and the Auger electron through PostCollisionInteraction were found to dominate the spectrum. The new assignments were in accord with the quantum defect values obtained for the high Rydberg series for singly charged ionic Xe$+$5$p(^{\mathrm{1}}S_{\mathrm{0}})$\textit{ ml}. [Preview Abstract] 

D1.00192: Controlling Electron Dynamics of Oriented Molecules Using Attosecond Pulses S. Miyabe, R. Lucchese, T. Rescigno, K. Midorikawa, C. W. McCurdy Attosecond pulses offer routes to study and potentially manipulate ultrafast electron dynamics of atoms and molecules on their intrinsic time scale, and therefore attracted attention from various disciplines. In this report we show that for a molecule, oriented in space and excited by an attosecond pulse, the amount of electronic coherence left in the ion depends not only on the orientation of the electric field polarization vector in the molecularframe, but also on the angular distribution in molecularframe of electrons ejected in different ionization channels. In our numerical simulation we use onephoton single ionization amplitudes calculated using the complexKohn variational method, and we express the amount of coherence in the ion in terms of the (N+1)electron reduced density matrix of the full Nelectron system of the ion plus ionized electron. [Preview Abstract] 

D1.00193: Theoretical studies on the mechanisms of laser rust removal Yupei Wang, Zunyue Zhang, Guigeng Liu, Feng Song Our studies introduce the threelayer model of laser rust removal by rotational mirror scanner and develop dry laser cleaning model Firstly, theoretically simulate the temperature field of the rotational mirror scanner. Use the superposition model of the instantaneous thermal source point from a point to a line, from a line to an area, to simulate the temperature field distribution of rust and iron with thermal source on its surface and how it varies with time. And then take the temperature field distribution of rotational mirror scanner as the thermal load and use ANSYS to solve the thermal conductivity equations with complicated boundary conditions, and calculate the temperature field distribution it can be found that the temperature of the rust surface reaches the melting even the boiling point of the rust, so the rust can be removed by the ablation effect. From the thermal stress distribution of rust and iron in the depth orientation, the thermal stress existed in the rust and iron is large enough to remove the last rust layer in one time. So ablation layer, thermal stress removal layer and substrate consist of the threelayer model of laser rust removal by rotational mirror scanner. [Preview Abstract] 

D1.00194: Rapid prototyping of versatile atom chips for atom interferometry applications. Brian Kasch, Matthew Squires, Spencer Olson, Bethany Kroese, Eric Imhof, Rudolph Kohn, Benjamin Stuhl, Stacy Schramm, James Stickney We present recent advances in the manipulation of ultracold atoms with exvacuo atom chips (i.e. atom chips that are not inside to the UHV chamber). Details will be presented of an experimental system that allows direct bonded copper (DBC) atom chips to be removed and replaced in minutes, requiring minimal reoptimization of parameters. This system has been used to create BoseEinstein condensates, as well as magnetic waveguides with precisely tunable axial parameters, allowing double wells, pure harmonic confinement, and modified harmonic traps. We investigate the effects of higher order magnetic field contributions to the waveguide, and the implications for confined atom interferometry. [Preview Abstract] 

D1.00195: Beam splitter for squeezed light Weizhi Qu, Jian Sun, Eugeniy Mikhailov, Irina Novikova, Heng Shen, Yanhong Xiao A conventional beam splitter can split classical light beams, but when used for squeezed light, the nonclassical property is often lost at the beam splitter output. Here, we demonstrate a beam splitter made of moving atoms that can split squeezed light. Squeezed vacuum is generated by a degenerate fourwavemixing (FWM) process in one location (Ch1) of a wallcoated Rb vapor cell, and then due to coherent diffusion of ground state coherence of the atoms within the cell, squeezed vacuum can be generated in a different location (Ch2) of the cell where no squeezing would exist without the presence of the Ch1, because of a relatively weak laser input. We attribute the phenomenon to FWM enhanced by coherence transfer. This effectively forms a beam splitter for squeezed light. We built a simple model that produces results in qualitative agreement with our experimental observations. [Preview Abstract] 

D1.00196: Highfidelity spatial addressing of $^{43}\text{Ca}^+$ qubits using nearfield microwave control Diana Prado Lopes Aude Craik, Norbert Linke, David Allcock, Martin Sepiol, Thomas Harty, Christopher Ballance, Derek Stacey, Andrew Steane, David Lucas Individual addressing of qubits is essential for scalable quantum computation. Spatial addressing allows unlimited numbers of qubits to share the same frequency, whilst enabling arbitrary parallel operations. We present the latest experimental results obtained using a twozone microfabricated surface trap designed to perform spatial, nearfield microwave addressing of longlived $^{43}\text{Ca}^+$ "atomic clock" qubits held in separate trap zones (each of which feature four integrated microwave electrodes) [1],[2]. Microwave near fields generated by multielectrode chip ion traps are often difficult to faithfully simulate and a simple method of characterizing and testing trap chips before placement under ultrahigh vacuum would significantly speed up trap design optimization. We describe a printed circuit board antenna for use in mapping microwave nearfields generated by iontrap electrodes. The antenna is designed to measure fields down to $100\mu$m away from trap electrodes and to be impedance matched at a desired spot frequency for an improved signal to noise ratio in field measurements. References: [1] D. P. L Aude Craik et al, arXiv:1601.02696 (2016); [2] D. P. L Aude Craik et al, Appl. Phys. B 114, 3 10 (2014) [Preview Abstract] 

D1.00197: Study of the Incident Angles and SPP(Surface Plasmon Polaritons) in the Nano Scaled Materials Richard Kyung, JayYoung Cho In this study, SPP(Surface Plasmon Polaritons) in multilayered nano structures, which consist of metals and dielectrics, have been analyzed using numerical and computational simulation. The purpose of this research is to find incident angles, and observe dispersions and plasmon polaritons occurring inside the materials when a laser beam is absorbed by the structure. The setup of the models consisted of air, metal oxide, metal, and prism. Numerical computer programs such as COMSOL and Matlab are used to analyze the phenomenon. Modes of SPP(Surface Plasmon Polaritons) have been observed and calculated for the multilayered metals and metal oxides. The accurate incident angle, dispersion, magnetic field inside the material and the effective index are found to be different for each model. [Preview Abstract] 

D1.00198: The weak measurement process and the weak value of spin for metastable helium $2^{3}S_{1}$ Vincenzo Monachello, Peter Barker, Robert Flack, Basil Hiley An experiment is being designed and constructed in order to measure the weak value of spin for an atomic system. The principle of the ``weak measurement" process was first proposed by Aharonov, Albert and Vaidman [1], and describes a scenario in which a system is weakly coupled to a pointer between welldefined pre and postselected states. This experiment will utilise a pulsed supersonic beam of spin1 metastable Helium (He*) atoms in the $2^{3}S_{1}$ state. The spin of the preselected He* atoms will be weakly coupled to its centreofmass. During its flight, the atomic beam will be prepared in a desired quantum state and travel through two inhomogeneous magnets (weak and strong) which both comprise the ``weak measurement" process. The deviation of the postselected $m_{s} =+1$ state as measured using a microchannel plate, phosphor screen and CCD camera setup will allow for the determination of the weak value of spin. This poster will report on the methods used and the experimental realisation. \begin{thebibliography}{1} \bibitem{AAV} Aharonov Y, Albert D Z and Vaidman L 1988 {\it Phys. Rev. Lett.} {\bf 60} 135154 \end{thebibliography} [Preview Abstract] 

D1.00199: Two Dimensional Grating MagnetoOptical Trap in $^{\mathrm{87}}$Rb Eric Imhof, Bethany Kroese, Matthew Squires We present the realization of a two dimensional grating magnetooptical trap (2D GMOT) in $^{\mathrm{87}}$Rb. Ongoing efforts to characterize the output beam are detailed. We describe our recent work to load a 3D grating MOT with a 2D GMOT, and our expectations for performance, loading rates, and efficiency gains. Our system integrates exvacuo atom chips to provide precisely tunable magnetic fields for ease of alignment and integration into larger cold atom experiments. [Preview Abstract] 

D1.00200: Manipulating polarization distribution of tightly focused vector optical fields Guigeng Liu, Chenghou Tu, Yupei Wang, Dan Wang, Xi Cheng, Juan Liang, HuiTian Wang We present a method to manipulate the polarization distribution of the focal plane, which is realized by controlling the polarization and amplitude of incident optical fields. Vector optical fields with arbitrary amplitude and polarization distribution can be generated based on a spatial light modulator and a common path interferometer with the aid of a 4f system, and the polarization distribution in focal fields is numerically studied. When incident optical fields is centrosymmetric, the ellipticity of focal fields is the same as that of incident fields when the ellipticity keeps constant; however, if the ellipticity of incident optical fields is not constant, the ellipticity for focal fields is different from the input one. For the case that the intensity of incident fields is not centrosymmetric, the ellipticity of its focal fields is not same as input fields when its ellipticity keeps constant and orientation is inhomogeneous, and it is also the case for the condition that the ellipticity is not constant. These findings are the result of interferences of brokensymmetry input fields. The results can be helpful in trapping of anisotropic particles and exciting the anisotropic materials. [Preview Abstract] 

D1.00201: Simple Digital FeedForward Circuit to Compensate for AOM Thermal Lensing Joshua Hill, James Aman, Thomas Killian I demonstrate a simple digital feedforward circuit which, when combined with twofrequency radio frequency (RF) electronics, maintains constant total RF power driving an acoustooptic modulator (AOM). Consistency in total power is desirable to mitigate thermal lensing effects that otherwise displace and misshape the laser beam when the primary frequency drive RF power is changed to, for example, alter the laser power in a diffracted beam. The Arduinobased feedforward circuit is costeffective, quick to implement, and easily modified. [Preview Abstract] 

D1.00202: Progress Towards Laser Cooling and Trapping Gadolinium Upendra Adhikari, Clayton Simien Lanthanide elements are of interest because of their potential for investigating next generation optical clock transitions, novel nonS ground state ultracold collisions, and the physics of quantum degenerate dipolar gases. We present our progress towards laser cooling and trapping atomic Gadolinium (Gd). A magnetooptical trap is the first step towards precision measurements, ultracold collision studies, and for probing dipolar physics of Gd. The design, construction, and performance of the apparatus will be presented. [Preview Abstract] 

D1.00203: Laser and Optical Subsystem for NASA's Cold Atom Laboratory James Kohel, James Kellogg, Ethan Elliott, Markus Krutzik, David Aveline, Robert Thompson We describe the design and validation of the laser and optics subsystem for NASA's Cold Atom Laboratory (CAL), a multiuser facility being developed at NASA's Jet Propulsion Laboratory for studies of ultracold quantum gases in the microgravity environment of the International Space Station. Ultracold atoms will be generated in CAL by employing a combination of laser cooling techniques and evaporative cooling in a microchipbased magnetic trap. Laser cooling and absorption imaging detection of bosonic mixtures of ${}^{87}$Rb and ${}^{39}$K or ${}^{41}$K will be accomplished using a highpower (up to 500~mW exfiber), frequencyagile dual wavelength (767~nm and 780~nm) laser and optical subsystem. The CAL laser and optical subsystem also includes the capability to generate highpower multifrequency optical pulses at 784.87~nm to realize a dualspecies Bragg atom interferometer. [Preview Abstract] 

D1.00204: Sensitivity improvements to the YbF electron electric dipole moment Isabel Rabey, Jack Devlin, Ben Sauer, Jony Hudson, Mike Tarbutt, Ed Hinds The electron is predicted to have a small electric dipole moment (EDM). The Standard Model (SM) predicts the EDM to be too small to ever detect at $d_{e}<10^{38}$ e.cm. However, many extensions of the SM that suggest additional processes, predict the electron’s EDM to be within a measurable regime of both current and proposed experiments. This poster presents some of the technical improvements made to the YbF electron EDM experiment since the last measurement. We have increased the statistical sensitivity of our interferometer by increasing the number of YbF molecules that participate in the experiment and by increasing their detection probability. We demonstrate several hardware developments that combine laser, microwave and rf fields which, when applied to YbF, can pump six times more population into the initial measurement state. In the detection region we have used techniques developed for molecular laser cooling, including resonant polarisation modulation, to dramatically increase the number of scattered photons by a factor of 10. Including other improvements, the statistical uncertainty of our measurement is expected to be reduced by a factor of 90, allowing us to search for physics beyond the SM and below the recent upper limit of $d_{e}<8.9\times10^{29}$ e.cm. [Preview Abstract] 

D1.00205: TwoPhoton Spectroscopy in Rb for an Optical Frequency Standard Kyle Martin, Gretchen Phelps, Nathan Lemke, Daniel Blakley, Christopher Erickson, John Burke The Air Force Research Laboratory is pursuing optical atomic clocks for navigation and timing applications. Optical clocks are of particular interest owing to their very high oscillation frequencies. We present an optical rubidium atomic frequency standard (ORAFS), based upon a twophoton transition at 778 nm, that utilizes readily available commercial offtheshelf components. Compared to existing GPS clocks, ORAFS offers reduced shortterm instability ($7 \times 10^{13}/ \sqrt{\tau}$), improved manufacturability, and competitive size, weight, and power, making it an attractive candidate for future space operation. [Preview Abstract] 

D1.00206: Using Tensor Light Shifts to Measure and Cancel a Cell's Quadruopolar Frequency Shift Larry Hunter, Stephen Peck, Nathanael Lane, Daniel Ang We have developed a new technique that uses the tensor light shift to measure and cancel the frequency shift produced by the quadrupolar anisotropy of a vapor cell. We demonstrate the technique on the 6S$_{\mathrm{1/2}}$, $F \quad =$ 4 level of Cs using the D1 transition. The method extends our ability to study quadrupolar wall interactions beyond diamagnetic atoms. We have deduced the twist angle per wall adhesion for cesium on an alkene coating to be about 1.4 mrad. This value is about 37 times larger than the twist angle observed in $^{\mathrm{131}}$Xe, suggesting that it is not produced by the interaction of the nuclear quadrupole moment with a collisional electricfield gradient. Alternative mechanisms that may be responsible for the observed quadrupolar frequency shifts are discussed. By cancelling the cellinduced quadrupole shift we have extended our cells' effective spinrelaxation times by as much as a factor of two. This cancellation improves magnetometer sensitivity in highly anisotropic cells and could reduce systematic uncertainties in some precision measurements. [Preview Abstract] 
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