Bulletin of the American Physical Society
49th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 63, Number 5
Monday–Friday, May 28–June 1 2018; Ft. Lauderdale, Florida
Session M01: Poster Session II 
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Room: Hall D 

M01.00001: Angular Dependence of Rydberg Atom Pair Interactions in a Blockaded Rb Gas Akbar Jahangiri Jozani, Luis Felipe Gon\c{c}alves, Luis G. Marcassa, James P. Shaffer We present our work on the angular dependence of Rydberg blockade in an external electric field. Experimental work is compared to detailed Rydberg atom pair interaction calculations. The interaction between 50S Rb atoms effectively trapped in 1dimension is investigated in an electric field. The electric field polarizes the atoms so that an angularly dependent dipoledipole interaction as well as a Van der Waalslike force determine the Rydberg blockade. In the experiments, an external electric field is tilted with respect to the trapping axis. Our calculations show that the effective interaction potential, V$_{eff}$, for electric fields of $\sim$13 V/cm and internuclear distances around the blockade radius R$_{bl}$, leads to a dipoledipole interaction parameter, C$_3$, approximately 7 times stronger than the free atom dipole moments in the electric field would suggest, which is in excellent agreement with experiment. The stronger effective dipole moments leading to a larger C$_3$ coefficient are the result of mixing of the asymptotic molecular states with high angular momentum molecular states induced by the static electric field around R$_{bl}$. [Preview Abstract] 

M01.00002: Ultrafast extreme ultraviolet photoemission without space charge Thomas Allison, Peng Zhao, Christopher Corder, Jin Bakalis, Amanda Muraca, Xinlong Li, Matthew Kershis, Michael White Time and Angleresolved photoelectron spectroscopy from surfaces can be used to record the dynamics of electrons and holes in condensed matter on ultrafast time scales. However, ultrafast photoemission experiments using extremeultraviolet (XUV) light have previously been limited by either spacecharge effects, low photon flux, or limited tuning range. In this article, we describe spacechargefree XUV photoelectron spectroscopy experiments with up to 5 nA of average sample current using a tunable cavityenhanced highharmonic source operating at 88 MHz repetition rate. The source delivers $ > 10^{11}$ photons/s in isolated harmonics to the sample over a broad photon energy range from 18 to 37 eV with a spot size of $58 \times 100 \; \mu$m$^2$. From photoelectron spectroscopy data, we place conservative upper limits on the XUV pulse duration and photon energy bandwidth of 93 fs and 65 meV, respectively. The high photocurrent and lack of space charge distortions of the photoelectron spectra enable timeresolved XUV photoemission experiments in a qualitatively new regime. [Preview Abstract] 

M01.00003: Calculations of longrange threebody interactions for Li($2\,^{2}S$)Li($2\,^{2}P$)Li$^+$($1\,^{1}S$) PeiGen Yan, LiYan Tang, ZongChao Yan, James F Babb We theoretically investigate longrange interactions for a threebody system involving a ground state Li atom, an excited P state Li atom and a ground state Li ion, denoted by Li($2\,^{2}S$)Li($2\,^{2}P$)Li$^+$($1\,^{1}S$), with highly accurate variationallygenerated nonrelativistic wave functions in Hylleraas coordinates. Using degenerate perturbation theory for the energies up to secondorder, we evaluate the coefficients $C_3$ of the firstorder induced and dipolar interactions, the coefficients $C_4$, $C_6$ and $C_8$ of the secondorder additive interactions and the coefficients $C_5$ and $C_7$ of the secondorder nonadditive interactions. Specific values of these coefficients will be given for different configurations of the three nuclei. The calculations are given for three likenuclei for the cases of hypothetical infinite mass Li nuclei, and of real finite mass $^6{}$Li or $^7{}$Li nuclei. The results may be useful in the study of ultracold plasma. [Preview Abstract] 

M01.00004: Current Status of Atomic Spectroscopy Databases at NIST Alexander Kramida, Yuri Ralchenko, Gillian Nave, Joseph Reader NIST's Atomic Spectroscopy Group maintains several online databases that can be accessed via https://www.nist.gov/pml/atomicspectroscopydatabases. Our main Atomic Spectra Database (ASD), now v. 5.5.2, contains critically evaluated data for \textgreater 270,000 spectral lines and 111,000 energy levels of almost all elements in the periodic table. Several thousand spectral lines and energy levels of C I, Cu II, V III, Y V, Sn III, Pt VIVIII have been added. Most of these additions are important for astrophysics, technology, and fusion research. A new LIBS interface to ASD is designed for modeling laserinduced breakdown plasma spectra. The Grotrian diagram interface has been reimplemented with enhanced interactive features. We continue weekly updates of our bibliography databases ensuring comprehensive coverage of current literature on atomic spectra. Our other popular databases, such as the Handbook of Basic Atomic Spectroscopy Data, searchable atlases of spectra of PtNe and ThAr lamps, and nonLTE plasmakinetics code simulations, continue to be maintained. The ThAr spectrum atlas has been redesigned implementing interactive plots and tables. [Preview Abstract] 

M01.00005: Spectroscopic study of the 7p J$=$1/2 and 7p J$=$3/2 states in neutral cesium133 Will Williams, MariaTeresa Herd, Bruce Hawkins Doppler free spectroscopy was performed on the 7p J$=$1/2 and 7p J$=$3/2 states in neutral cesium133 using a frequency doubled titanium sapphire laser stabilized to a temperature stabilized ultralow expansion optical cavity. The absolute frequencies for the centers of gravity of the two states were measured representing an improvement of a factor of 650 and 500 over previously reported measurements, respectively.[1] The magnetic dipole and electric quadrupole constants were also measured and found to be consistent with previously published values. [1] H. Kleiman, J. Opt. Soc. Am. \textbf{52}, 441 (1962) [Preview Abstract] 

M01.00006: Plasmoncoupled Resonance Energy Transfer: Beyond Dipole Approximation Kobra Nasiri Avanaki, Wendu Ding, George C. Schatz In this work, we present a comprehensive theoretical and computational study on plasmoncoupled resonance energy transfer (PCRET) in inhomogeneous absorbing and dispersive media beyond dipole approximation. The method extends the Förster theory for the RET continuations between large particles (size comparable to the distance between them), in which the higher multipole transitions specifically magnetic dipole and electric quadrapole transitions play significant roles. In our new formulation, we show that the transition matrix elements for RET can be expressed in terms of the donor and acceptor transition dipole/quadrapole moments and the external polarization fields generated by the donor, evaluated at the position of the acceptor. Numerical calculations based on finite difference timedependent (FDTD) method were performed on example particles, and compared with the analytical results in vacuum. The method yields a numerically simple and computationally practical approach for PCRET calculations in relatively large particles particularly in biology, optical switching, solar cells, where energy transfer processes typically take place in inhomogeneous absorbing and dispersive media. [Preview Abstract] 

M01.00007: Observation of Mollow triplet transfer in 3He atoms Yuanzhi Zhan, Xiang Peng, Sheng Li, He Wang, Liang Zhang, Jingbiao Chen, Hong Guo We experimentally observed the Mollow triplet (MT) induced with an oscillating magnetic field and studied the dressed states of 3He atoms. The MT signatures from the ground states of 3He atoms are transferred to the metastable states by metastabilityexchange collisions (MECs) and then measured with optical detection. The transfer process is simulated with angular momentum equations, and the simulation results are corresponding to the experimental data. The frequency interval of the sidebands is linear with the amplitude of the resonant oscillating magnetic field, which shows the possibility applying the measurement of the amplitude of the oscillating magnetic fields. The center peak of MT can be controlled by the optical pumping laser, which leads to realize the new scheme of optical modulation. [Preview Abstract] 

M01.00008: Monte Carlo and numerical study of pumping $K_{\alpha}$ resonance fluorescence in highZ nanovehicles for enhancing radiation therapy Maximillian Westphal, Sultana Nahar, Anil Pradhan Using the Monte Carlo code GEANT4 developed by CERN as well as a custom code called PHOTX, we have studied fluorescence and Auger electrons in a variety of nanoparticles as a method to improve tumor irradiation. We used GEANT4 to simulate photons from quasimonochromatic, monochromatic, and traditional broadband medical Xray sources interacting with heavy element nanoparticles designed to enhance Xray absorption [1]. Nanoparticles were composed of gold, platinum, or gadolinium, were varied in size from 220 nm, and were varied in shape including rods, spheres, and cubes. We also have made developments to the code PHOTX to better implement Rabi floppings in order to determine intensities needed to pump $K_{\alpha}$ resonance fluorescence in highZ nanovehicles [2].\newline [1] M. S. Westphal et al., Phys. Med. Biol, 62: 63616378, 2017.\newline [2] S. N. Nahar and A. K. Pradhan, JQSRT, 155: 3248, 2015. [Preview Abstract] 

M01.00009: The Ruby Phosphorescence Laboratory: Measuring the $^2$ETerm RoomTemperature Lifetime of Cr$^{3+}$. Anthony Calamai, J. Hinds, W. Dulaney, T. Dula, J. Burris, B. Hester Many existing advanced laboratory experiences associated with the metastable $^2$E term of Cr$^{3+}$ in ruby, which gives rise to the Rlines at 692.7 and 694.3 nm, focus on a roomtemperature measurement of the radiative lifetime of the $^2$E term.These projects typically use commercially available ruby spheres for which the manufacturer(s) only state an $\sim $ 2percent chromium concentration. The uncertainty in Cr$^{3+}$ concentration represents one source of systematic error for this laboratory experience. In our local work developing a costeffective laboratory experience in atomic phosphoresce, we noted a lack of consistency in the literature for the lifetime of the Cr$^{3+}$ $^2$E term. We present our results and corrections for systematic issues that make this project a more rewarding experience for students. Our result for the roomtemperature radiativelifetime for the $^2$E term is 3.3 $\pm $ 0.1 ms; which, unlike some more recent reports (e.g. [1]), compares favorably with that of Nelson and Sturge [2]. [1] Espositi, C.D. and Bizzocchi, L., J. Chem. Ed., V84, 1316, (2007). [2] Nelson, D.F. and Sturge, M.D., Phys. Rev., V137 #4A, A1117, (1965). [Preview Abstract] 

M01.00010: Atomic data of lowcharged Sn ions for lithography applications James Colgan, A. J. Neukirch, D. P. Kilcrease, J. Abdallah, M. E. Sherrill, C. J. Fontes, P. Hakel The intense emission of tin plasma in the 13.5~nm wavelength band has long been recognized for its potential as a powerful EUV source with important lithography applications. The efforts to predict the plasma properties of Sn that produce these intense emission features are complicated by the complex atomic structure of the Sn ions in question. We have examined the atomic structure and opacity of Sn at low temperatures ($<$ 50 eV), where these ions dominate the absorption features. In recent studies, we found that the use of intermediatecoupling, as compared to full configurationinteraction, is not adequate to obtain accurate line positions of the important boundbound transitions in Sn. One requires full configurationinteraction to properly describe the strong mixing between the various n=4 subshells that give rise to the $\Delta$n=0 transitions that dominate the opacity spectrum at low temperatures. Since calculations that include full configurationinteraction for large numbers of configurations quickly become computationally prohibitive, we have explored hybrid calculations. Our calculations are performed using the Los Alamos suite of atomic physics codes. Preliminary results indicate that our models find good agreement with measurements from laserproduced plasmas. [Preview Abstract] 

M01.00011: Double photoionization of Beryllium atoms using affective charge approximation. Hari P. Saha We plan to report the results of our investigation on double photoionization Kshell electrons from Beryllium atoms. We will present the results of triple differential cross sections at excess energy of 40 eV using our recently extended MCHF method [1]. We will use multiconfiguration Hartree Fock method to calculate the wave functions for the initial state. The final state wave functions will be obtained in the angle depended Effective Charge approximation [24] which accounts for electron correlation between the two final state continuum electrons. We will discuss the effect of core correlation and the valence shell electrons in the triple differential cross section. The results will be compared with the available accurate theoretical calculations and experimental findings. [1] Hari P. Saha, Phys. Rev. A 87, 042703 (2013). [2] M.R.H. Rudge, Rev. Mod. Phys. 40, 564 (1968). [3] D. Proulox and R. Shakeshaft,, Phys. Rev A 48, R875 (1993). [4]; M. Pont and R. Shakeshaft, Phys. Rev. A51, R2676 (1995). [Preview Abstract] 

M01.00012: Photon Ionization along the Fe Isonuclear Sequence J.P. Colgan, M. S. Pindzola A timedependent closecoupling method is used to calculate one and two photon ionization cross sections along the Fe isonuclear sequence. Specific calculations are made for the ground configurations of Fe+14, Fe+15, Fe+16, and Fe+17. These calculations are in support of efforts to compare theory and experiment for iron opacities in hot dense plasmas. [Preview Abstract] 

M01.00013: Photoionization of C$_{\mathrm{\mathbf{60}}}$\textbf{: Effects of correlation on cross sections and angular distributions of valence subshells} A. Ponzi, P. Decleva, S. T. Manson Calculations of the photoionization of all of the 32 valence subshells, from the outermost 6h$_{\mathrm{u\thinspace }}$to the innermost 2a$_{\mathrm{g}}$, of the free C$_{\mathrm{60}}$ molecule have been performed using a timedependent density function theory (TDDFT) methodology within the framework of a fully molecular model [1]. Cross sections and photoelectron angular distribution $\beta $ parameters have been obtained and the results have been broadened to simulate vibrational structure. In addition, the calculations are performed at the ordinary density functional theory (DFT) level, basically centralfield calculations, in an effort to understand the role of correlation in the photoemission process. The spectra are fraught with narrow autoionizing and shape resonances which make then quite difficult to analyze, along with the much broader confinement resonances [2]. The narrow shape resonances show up quite clearly in the photoionization at energies above the lowest 2a$_{\mathrm{g\thinspace }}$threshold and in the 2a$_{\mathrm{g\thinspace }}$cross section itself where autoionization is not possible. [1] A. Ponzi, P. Decleva and S. T. Manson, Phys. Rev. A 92, 023405 (2015); [2] J.P. Connerade, V. K. Dolmatov and S. T. Manson, J. Phys B \textbf{33}, 2279 (2000). [Preview Abstract] 

M01.00014: Insights on the Dissociation Dynamics of Ammonia Through CoreHole Molecular Frame XRay Photoelectron Angular Distributions Cynthia Trevisan, Joshua Williams, Thorsten Weber, Thomas Rescigno, Reinhard D\"orner, Till Jahnke, Markus Sch\"offler, Allen Landers, Clyde McCurdy We present experimental and theoretical results for the angular dependence in the body frame of electrons ejected from the core orbitals of ammonia that verify the imaging effect predicted earlier by which the molecular frame photoelectron angular distributions (MFPADs) for removing an electron from a 1s orbital effectively image the geometry of a class of molecules. Ammonia with a 1s vacancy undergoes double Auger decay to produce, in one channel, 3 protons and a neutral N atom, allowing the determination of the MFPAD in a fourparticle coincidence experiment. Calculations have predicted an imaging effect in a class of molecules whereby the electron ejected by core photoionization has the tendency to follow molecular bonds if averaged over directions of polarization of the incident Xray beam. We combine experimental results to quantum chemistry calculations to investigate the dissociation dynamics of ammonia after double Auger decay. Our measurements employ the COLTRIMS method and the calculations were performed with the Complex Kohn Variational method. [Preview Abstract] 

M01.00015: Inner shell photoionization of Mg and Ca isonuclear sequence using RMCTD Aarthi Ganesan, P. C. Deshmukh, S. T. Manson The influence of removing outer electrons on the inner 2s subshell photoionization cross section and photoelectron angular distribution is studied along the isonuclear sequences of Mg and Ca using the relativistic random phase approximation \textit{with} relaxation (RRPAR) [1] and the relativistic multiconfiguration TammDancoff (RMCTD) approximation [2]. Earlier calculations of isonuclear sequences concluded that the photoionization cross sections of inner shells remain unaffected by the removal of outershell electrons, except for a shift in the threshold [3]. Studies were carried out using the RRPA [4, 5] and the RRPAR formalism to include relaxation effects for 2s subshell of Ar and Mg [6] which showed that the innershell crosssections are affected somewhat by corerelaxation, while the angular distribution from the innershells is affected by the removal of outer electrons \textit{even} in the absence of corerelaxation. The present work shows the variation of the 2s cross section and photoelectron angular distribution from the isonuclear ions of Mg and Ca using RMCTD. Also, the effect of core relaxation of the 2s subshell of the isonuclear sequence of Ca is reported using RRPAR, in addition to RMCTD. [1] V. Radojevic \textit{et al} Phys. Rev. A. \textbf{40, }727 (1989); [2] V. Radojevic and, W. R. Johnson, Phys. Rev. A\textbf{ 31, }2991 (1985); [3] S. T. Manson and J. W. Cooper, Phys. Rev. \quad \underline {\textbf{165, }}\underline {126} (1968); [4] W. R. Johnson and, C. D. Lin, Phys. Rev. A \quad \underline {\textbf{20, }}\underline {964} (1979); [5] G. Nasreen \textit{et al} Phys. Rev. \quad A \quad \underline {\textbf{40, }}\underline {6091} (1989); [6] G. B. Pradhan \textit{et al} Phys. Rev. A \quad \underline {\textbf{80, }}\underline {053416} (2010). [Preview Abstract] 

M01.00016: Photoionization studies of singlycharged halogen anions @C$_{\mathrm{60}}$ Ruma De, Dakota Shields, Mohamed Madjet, Steven T. Manson, Himadri Chakraborty The ground states of endofullerene molecules comprised of atomically closedshell singlycharged halogen anions Cl$^{\mathrm{}}$, Br$^{\mathrm{}}$, and I$^{\mathrm{}}$ confined in C$_{\mathrm{60}}$ are modeled in a spherical KohnSham local density approximation (LDA) by employing the Leeuwen and Baerends exchangecorrelation functional [1]. The core of sixty C$^{\mathrm{4+}}$ ions is jelliumized [2] to ignore the carbon $K$shell structures. A timedependent LDA (TDLDA) method [3] is subsequently applied to calculate the photoionization parameters of the molecules in the dipole coupling frame. The cross sections for the bonding and antibonding hybrid levels of the molecules in comparison with the free anion valence n$p$ results display two broad energy regions: (i) plasmonenhanced lowenergy domain and (ii) higher energy region of broad oscillations from the coherence of cavity and confinement effects. However, results compared among these molecules reveal significant differences in the details. Further comparisons with the results from Ar,Kr,Xe@C$_{\mathrm{60}}$, the nearby closedshell neutrals in the periodic table, unravel effects of transitions from neutrals to anions within identical electron configurations. [1] R. van Leeuwen et al, Phys. Rev. A \textbf{49}, 2421 (1994); [2] M. E. Madjet et al., Phys. Rev. A \textbf{81}, 013202 (2010); [3] Choi et al., Phys. Rev. A \textbf{95}, 023404 (2017). [Preview Abstract] 

M01.00017: Photoemissions from hybrid states in metastable halogenendofullerene molecules Dakota Shields, Ruma De, Mohamed Madjet, Steven T. Manson, Himadri Chakraborty For the Cl@C$_{\mathrm{60}}$ endofullerene we consider the transfer of a C$_{\mathrm{60}} \quad \pi $ electron of $p$ angular character to the outer 3$p$ shell of confined Cl forming a metastable molecule Cl$^{\mathrm{}}$@C$_{\mathrm{60}}^{\mathrm{+}}$. The ground state of this molecule is modeled in a spherical local density approximation (LDA) augmented by the Leeuwen and Baerends exchangecorrelation functional [1] where the core of sixty C$^{\mathrm{4+}}$ ions is jelliumized [2]. A timedependent LDA (TDLDA) method [3] is subsequently applied to calculate the dipole photoionization parameters of the molecule. Cross sections for the photoemission from levels hybridized between the C$_{\mathrm{60}}$ level containing the $p$ hole and the Cl$^{\mathrm{}}$ 3$p$ level show the coherence between C$_{\mathrm{60}}$ plasmonic and atomic Coulomb dynamics. At higher energies, the mixing of confinement and cavity oscillations [4] determines the structures in the spectra. Calculations are also extended to similar hybrid levels of metastable Br$^{\mathrm{}}$@C$_{\mathrm{60}}^{\mathrm{+}}$ and I$^{\mathrm{}}$@C$_{\mathrm{60}}^{\mathrm{+}}$ Detailed comparison among the results provides deeper insights into the role of evolving halogen structures to influence the molecular photoionization. [1] R. van Leeuwen et al, Phys. Rev. A \textbf{49}, 2421 (1994); [2] M. E. Madjet et al., Phys. Rev. A \textbf{81}, 013202 (2010); [3] Choi et al., Phys. Rev. A \textbf{95}, 023404 (2017); [4] Potter et al., Phys. Rev. A \textbf{82}, 033201 (2010). [Preview Abstract] 

M01.00018: InterchannelCouplingInduced Structure in Atomic Photoionization of Outer Shells Above InnerShell Thresholds David Keating, Steven Manson, Pranawa Deshmukh Interchannel coupling is a very important contributor to the atomic photoionization cross section, especially in the cross sections of outer subshells near the thresholds of inner subshells where there is a discontinuity between the cross section below the opening of the threshold and just above the opening of the threshold [1]. To explore these discontinuities, a theoretical study of the photoionization cross sections of the noble gas atoms has been performed using the relativistic random phase approximation (RRPA) methodology [2]. In order to fully investigate the effects of interchannel coupling, calculations have been performed with and without interchannel coupling, which is possible within the framework of the RRPA methodology, allowing us to assess the importance of various levels of interchannel coupling. The results show significant effects in essentially all case, thereby demonstrating that threshold. [1] W. Drube et al, J. Phys. B 46, 245006 (2013); [2] W. R. Johnson and C. D. Lin, Phys. Rev. A 20, 964 (1979). [Preview Abstract] 

M01.00019: Ionization, single and double electron capture in protonAr collisions Alba Jorge, Clara Illescas, Luis Mendez, Ismanuel Rabadan The formation of anions in collisions of positive ions with atoms has been an usual subject of study in atomic physics due to its importance in different fields, such as astrophysics, plasma physics and surface physics. Special interest has been focused on the formation of H$^$ in proton collisions with different targets, for which both theoretical and experimental studies have been carried out. From a theoretical point of view, the double electron capture process giving rise to the formation of H$^$ turns out to be impracticable with oneelectron methods, since its probability is two orders of magnitude smaller than those of oneelectron processes. A theoretical study on the H$^+$ + Ar collision has been carried out with a manyelectron semiclassical treatment, with an expansion in a basis of electronic functions of the ArH$^+$ quasimolecule and the twoactive electron switchingClassicalTrajectoryMonteCarlo method (sCTMC). Total cross sections for formation of H, H$^$ and electron production in H$^+$ + Ar collision at energies between 100 eV and 200 keV will be presented at the conference. [Preview Abstract] 

M01.00020: Quantum versus classical description of inelastic processes in chargedparticle collisions with the water molecule. Alba Jorge, Marko Horbatsch, Clara Illescas, Tom Kirchner Inelastic processes following the impact of fast ions on molecules of biological importance have received a lot of attention in recent years. Special interest has been focused on the ionization of the water molecule due to its relevance in hadron therapy. The well known Classical Trajectory Monte Carlo (CTMC) method, commonly used for describing the initial state and time evolution of atomic systems, can be applied to the characterization of molecular ones as well, e.g., through multicenter potentials. A classical description of molecular orbitals (MOs) poses, however, some important differences compared to atomic orbitals, such as the nondegeneracy of the MOs and the electron interaction with a noncentral potential. The Li$^{3+}$ + H$_2$O collision system has been studied theoretically with the quantummechanical TwoCenter Basis Generator Method (TCBGM), reporting cross sections which agree with measured data. A detailed comparison of these two methodologies on the level of orientationdependent results for individual MOs sheds light on the accuracy of the classical description of the water molecule. This comparison will be presented at the conference. [Preview Abstract] 

M01.00021: Destruction of veryhigh$n$ Rydberg atoms in RydbergRydberg collisions R G Fields, R Brienza, F B Dunning, S Yoshida, J Burgdörfer The destruction of veryhigh$n$ strontium Rydberg atoms in RydbergRydberg collisions is examined in an atomic beam. ~Rydberg blockade is exploited to produce a string of Rydberg atoms with approximately equal initial spatial separations but a distribution of velocities leading to subsequent collisions and Rydberg atom destruction through Penning ionization, which is monitored by measuring the time evolution of the high$n$ population. ~The data are analyzed using a Monte Carlo collision code that models Rydberg atom production together with their subsequent motions and collisions. ~Comparisons between model predictions and experimental data point to large collisional loss cross sections, on the order of 10$^{\mathrm{5}}$ cm$^{\mathrm{2}}$, that match those expected for hardsphere collisions, i.e., $\sigma =$ 4$\pi $R$_{n}^{\mathrm{2}}$ where R$_{n}=$ 2$n^{\mathrm{2}}$ is the atomic radius. [Preview Abstract] 

M01.00022: Quantum Rovibrational dynamics of CS in collision with H$_2$ Benhui Yang, Peng Zhang, Chen Qu, Phillip Stancil, J. Bowman, N. Balakrishnan, R. Forrey Carbon monosulfide has been widely observed in a variety interstellar regions. An accurate prediction of its abundance requires collisional rate coefficients with ambient gases. Available collisional rate coefficients are limited to rigidrotor calculations for a small range of rotational transitions in the vibrational ground state. In this work, we report the first sixdimensional (6D) PES for the CSH$_2$ system. The PES was computed using highlevel electronic structure theory and fitted using invariant polynomial method. Quantum scattering calculations were performed for rotational and rovibrational transitions of CS induced by H$_2$. Cross sections for rotational transitions from $j_1$=05 are compared with the results obtained within a rigidrotor model. For rovibrational transitions, statetostate and total quenching cross sections and rate coefficients were calculated for the vibrational quenching in CS($v_1=1, j_1$)+H$_2$($v_2=0, j_2$) $\rightarrow$ CS($v_1^{\prime}=0, j_1^{\prime}$)+H$_2$($v_2^{\prime}=0, j_2^{\prime}$) collisions, $j_1$=05. Cross sections for collision energies in the range 1 to 5000 cm$^{1}$ and rate coefficients ranging from 5 to 1000 K are presented for both paraH$_2$ ($j_2$=0) and orthoH$_2$ ($j_2$=1) collision partners. [Preview Abstract] 

M01.00023: Electronimpact excitation of Fe II Swaraj Tayal, Oleg Zatsarinny New extensive calculations are reported for electron collision strengths, rate coefficients and transitions probabilities for the wide range of transitions in Fe II. The collision strengths were calculated using the Bspline BreitPauli Rmatrix method. The MCHF method in connection with adjustable configuration expansions and semiempirical fineturning procedure is employed for an accurate representation of the target wave functions. The closecoupling expansion contains 340 finestructure levels of Fe II and includes all levels of the $3d^64s$, $3d^54s^2$, $3d^7$, $3d^64p$ configurations, plus a few lowest levels of the $3d^54s4p$ configuration. The effective collision strengths are obtained by averaging the electron collision strengths over a Maxwellian distribution of velocities at electron temperatures in the range from $10^2$ to $10^5$ K, and were tabulated for the 57630 transitions between all included finestructure levels. The present results considerably expend the existing data sets for Fe II, allowing more detailed treatment of the available measured spectra from different space observatories. Comparison with other calculations for collision rates and available experimental radiative rates is used to assess the likely uncertainties in the existing data sets. [Preview Abstract] 

M01.00024: Electron Impact Excitation Cross Sections for S$^{\mathrm{2+}}$ Swaraj Tayal, Oleg Zatsarinny Improved electron impact excitation cross sections calculation for finestructure transitions in S$^{\mathrm{2+}}$ have been performed using the Bspline BreitPauli Rmatrix method. The flexible nonorthogonal sets of spectroscopic and correlation radial functions are employed for an accurate representation of the target states and scattering functions. The closecoupling expansion includes 109 bound levels covering all possible terms of the ground 3s$^{\mathrm{2}}$3p$^{\mathrm{2}}$ and excited 3s3p$^{\mathrm{3}}$, 3s$^{\mathrm{2}}$3p3d, 3s$^{\mathrm{2}}$3p4s, 3s$^{\mathrm{2}}$3p4p, 3s$^{\mathrm{2}}$3p4d, 3s$^{\mathrm{2}}$3p5s, 3s$^{\mathrm{2}}$3p4f, 3s$^{\mathrm{2}}$3p5p, 3s3p$^{\mathrm{2}}$3d, and 3s3p$^{\mathrm{2}}$4s configurations. The calculated excitation energies of the target levels are in excellent agreement with experiment and represent an improvement over the previous calculations. The present results of cross sections are compared with a variety of other closecoupling and distortedwave calculations. The oscillator strengths are in good agreement with other theories and available experimental results. [Preview Abstract] 

M01.00025: Electronimpact excitation cross sections for Fe I Kedong Wang, Oleg Zatsarinny, Klaus Bartschat Extensive calculations are reported for electron collision strengths, rate coefficients, and transitions probabilities for a wide range of transitions in Fe I. The collision strengths were calculated using the Bspline BreitPauli Rmatrix approach [1]. The MCHF method in connection with adjustable configuration expansions and a semiempirical finetuning procedure was employed to accurately represent the target wavefunctions. The closecoupling expansion contained 221 $LS$ states of Fe I, including all levels of the $3d^6 4s^2$, $3d^7 4s$, $3d^8$, $3d^6 4s4p$, and $3d^7 4p$ configurations. Effective collision strengths were obtained by averaging the electron collision strengths over a Maxwellian distribution of speeds at electron temperatures from $10^2$ to $10^5$ K. The tabulated results for 24,531 transitions between all the above $LS$ terms considerably expand the few existing, sparse datasets for Fe I. They allow a more detailed analysis of the measured spectra from various space observatories and the nonlocal thermodynamic equilibrium modeling of latetype stars [2], for which large amounts of collisional data for the atomic species of interest are required. [1] O.~Zatsarinny, Comp.\ Phys.\ Commun.~{\bf 174} (2006) 273. [2] P.~S.~Barklem, A\&ARv~{\bf 24} (2016) 9. [Preview Abstract] 

M01.00026: Cross Sections and Spin Asymmetries for Electron Collisions with Lead. M. Van Eck, K. McNamara, D. V. Fursa, I. Bray, O. Zatsarinny, K. Bartschat We present angleintegrated and angledifferential cross sections as well as spin asymmetries for elastic and inelastic electron collisions with lead atoms. The results were obtained using the fully relativistic convergent closecoupling (RCCC)~[1] and the Dirac Bspline Rmatrix (DBSR)~[2] methods. They will be compared with experimental data and predictions from previous calculations. In particular, the spin asymmetries for the optically forbidden inelastic transitions from the ($6p^2)^3P_0$ ground state to other states of the $6p^2$ manifold, measured by Geesmann {\it et al.}~[3], are known to be very challenging for theory~[2]. We analyze the sensitivity of the predictions to the quality of the target description as well as the number of channels included in the closecoupling expansion. [1] D.\ V.\ Fursa and I.\ Bray, Phys.\ Rev.\ Lett.~{\bf 100} (2008) 113201. [2] O.\ Zatsarinny and K.\ Bartschat, Phys.\ Rev.\ A~{\bf 77} (2008) 062701. [3] H.\ Geesmann, M.\ Bartsch, G.\ F.\ Hanne, and J.\ Kessler, J.\ Phys.\ B~{\bf 24} (1991) 2817. [4] O.\ Zatsarinny, Y.\ Wang, and K.\ Bartschat, J.\ Phys.\ B~{\bf 46} (2013) 035202. [Preview Abstract] 

M01.00027: Electron Impact Excitation of Adenine in the VUV. J William McConkey, Joshuah Trocchi, Jeffery Dech, Wladek Kedzierski Dissociative excitation of adenine (C$_{\mathrm{6}}$H$_{\mathrm{5}}$NH$_{\mathrm{2}})$ into excited atomic fragments has been studied in the electron impact energy range from threshold to 300 eV. A crossed beam system coupled to a vacuum ultraviolet (VUV) monochromator is used to study emissions in the wavelength range from 110 to 200 nm. The beam of adenine vapor from a stainless steel oven is crossed at right angles by the electron beam and the resultant VUV radiation is detected in a mutually orthogonal direction. Excitation of H Lyman$\alpha $, the strongest feature in the spectrum, is considered in detail. [Preview Abstract] 

M01.00028: Anionic ground and metastable states formation in lowenergy electron fullerenes interactions: Regge pole investigation Alfred Z Msezane, Zineb Felfli Regge poles are generalized bound states. The hollow cage structure of fullerenes is conducive to metastable anionic states formation during the gentle electronfullerenes collisions. Our robust Regge pole methodology is used to probe for longlived metastable anionic formation in the fullerenes C$_{n} (n=$20, 24, 26, 28, 44, 70, 92 and 112) through the calculated elastic scattering total cross sections (TCSs). All the TCSs are found to be characterized by RamsauerTownsend minima, shape resonances and dramatically sharp resonances manifesting ground and metastable anionic formation during the collisions. The ground states anionic binding energies are found to match the measured electron affinities (EAs). Surprisingly, the small C$_{\mathrm{24}}$, exhibiting mild atomic behavior, has the largest EA, 3.79 eV among the investigated fullerenes. Therefore it could be suitable for use in organic solar cells to resist fullerene degradation by the photooxidation mechanism [1]. The large C$_{\mathrm{92}}$ and C$_{\mathrm{112}}$ and the small C$_{\mathrm{24}}$ fullerenes could be used to catalyze the oxidation of water to peroxide through their first metastable anions as well as serve as an inexpensive single nanocatalyst for water purification [2]. 1. E. T. Hoke \textit{et al}, \textit{Adv. Energy Mat.} \textbf{2,} 1351 (2012) 2. S. J. Freakley \textit{et al}, \textit{Science} \textbf{351}, 959 (2016) [Preview Abstract] 

M01.00029: Electron transfer, ionization, and excitation in collisions between protons and the ions Na$^{10+}$ and Mg$^{11+}$. Thomas Winter Coupledstate cross sections are being determined for electron transfer, ionization, and excitation in collisions between keVenergy protons and the hydrogenic ions Na$^{10+}$ and Mg$^{11+}$ initially in the ground state, 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$^{5+}$, and work reported at the 2016 and 2017 DAMOP meetings on the target ions N$^{6+}$, O$^{7+}$, F$^{8+}$, and Ne$^{9+}$. As in the more recent works, a basis of 60 Sturmians on each center is being used, as well as bases of several hundred Sturmians on the target nucleus and a single $1s$ function on the proton. For excitation and ionization, various singlecenter bases are also considered. The extent to which simple scaling rules with target nuclear charge $Z$ are valid is being examined further for direct excitation as well as ionization and electron transfer at intermediate energies near where the cross sections peak. [Preview Abstract] 

M01.00030: Target Kshell ionization for 3545 MeV $\rm{\bf F}^{\bf 7,8,9+}$ + Ar resulting in single and double capture David La Mantia, Nuwan Kumara, Asghar Kayani, John Tanis Cross sections for target Ar Kshell ionization associated with single and double electron capture, as well as the corresponding total capture cross sections, were determined for 3545 MeV $\rm{F}^{7+,8+,9+}$ projectiles. Previous work for Ar Kshell ionization was performed for fullystripped fluorine projectiles.\footnote{D. S. La Mantia, {\it et al}, NIMB {\bf 408}, 187 (2016)} This work was performed at Western Michigan University with the tandem Van de Graaff accelerator. The various chargestate beams collided with argon atoms in a differentially pumped cell. Surface barrier detectors were used to detect the chargechanged projectiles and a Si(Li) xray detector, placed at $90^{\rm{o}}$ to the incident beam, was used to measure coincidences of the Ar K x rays with the chargechanged ions. The results are compared to previous experiments where coincidence techniques were not employed.\footnote{J. R. Macdonald and F. W. Martin, PRA {\bf 4}, 1965 (1971)} The coincidence cross sections are about three orders of magnitude smaller than the total cross sections and the ratios for double to single capture are found to vary strongly with the incident charge state, with the ratios for $\rm{F}^{9+}$ exceeding unity. Possible explanations for this anomalous behavior are discussed. [Preview Abstract] 

M01.00031: Secondary electron production from ion precipitation at Jupiter: simultaneous and nonsimultaneous target and projectile processes in collisions of O$^{\mathrm{q+}}+$ H2 (q$=$08) Heman Gharibnejad, David Schultz, Thomas Cravens With the goal of improving the modeling of the effects of secondary electrons produced by energetic ion precipitation in Jupiter's atmosphere, we compute inelastic processes that occur simultaneously on the projectile (O$^{\mathrm{q+}}$, q$=$08)) and target (H2). Here projectile and target electron transitions, such as single ionization, are replaced by processes that include both nonsimultaneous and simultaneous electronic transitions on the target and projectile. These include, for example, single ionization, single ionization with simultaneous single projectile excitation, single ionization with double projectile excitation, single ionization with single projectile stripping, and single ionization with double projectile stripping. Using this set of simultaneous processes, we show, via Monte Carlo ion transport simulation, that improved representation of the energy deposition, measured by the stopping power, is obtained as compared to solely relying on nonsimultaneous processes. [Preview Abstract] 

M01.00032: Excited state positronium formation from C$_{\mathrm{60}}$ and C$_{\mathrm{240\thinspace }}$molecules PaulAntoine Hervieux, Anzumaan Chakraborty, Himadri Chakraborty There exists a broad landscape of positronium (Ps) formation studies by implanting positron beams on atoms, molecules, polymers, solids, liquids, surfaces/films, metalorganicframeworks and embedded nanostructures. Recently, ground state Ps formation studies using the C$_{\mathrm{60}}$ molecule as a target have been carried out [1,2]. Due to the dominant electron capture from the fullerene shell region and the spatial dephasing across the shellwidth, a powerful diffraction effect was found to underpin the process of Ps formation in C$_{\mathrm{60}}$. In the current work, we access excited state Ps formations from both C$_{\mathrm{60}}$ and C$_{\mathrm{240}}$ fullerenes. Results reveal significant structures in the cross section as a function of both the impact energy and the Ps level  structures that arise from positronfullerene shortrange interactions. Fullerenes are modeled by a localdensity approximation (LDA) approach [3] and the Ps formation is treated by the continuum distortedwave finalstate (CDWFS) approximation [4]. The work may motivate application of the Ps formation spectroscopy to gas phase nanoparticles and access fullerenelevel as well as Psleveldifferential measurements. [1] Hervieux et al., Phys. Rev. A \textbf{95}, 020701 (R) (2017); [2] Chakraborty et al., J. Phys.: Conf. Series \textbf{875}, 072002 (2017); [3] Choi et al., Phys. Rev. A \textbf{95}, 023404 (2017); [3] Fojon et al., Phys. Rev. A \textbf{54}, 4923 (1996). [Preview Abstract] 

M01.00033: Positronium formation in the forward direction in positronC$_{\mathrm{60\thinspace }}$collisions PaulAntoine Hervieux, Himadri Chakraborty Following the impact of positrons with matter the formation of exotic electronpositron boundpair, the positronium (Ps), is a vital process in nature. Varieties of target systems from atoms to smaller molecules to condensed matters have been accessed by the Ps formation spectroscopy. However, clusters and fullerenes in gasphase have largely been one uncharted target territories until the calculations recently reported by us [1,2]. To further motivate applications of this spectroscopy to fullerene targets and to access targetlevel as well as Psleveldifferential measurements, we now compute Ps formation cross sections in the forward collision direction within a very narrow angular range which is likely measurable by the existing technologies. The electronic structure of a C$_{\mathrm{60}}$ molecule is described by the localdensity approximation with LB94 exchangecorrelation functional [3]. The positron impact on C$_{\mathrm{60}}$ leading to the Ps formation is treated by the continuum distortedwavefinalstate approximation [4]. Comparisons with the angleintegrated result reveal more prominent diffraction resonances in the forward angle signal. [1] Hervieux et al., Phys. Rev. A \textbf{95}, 020701 (R) (2017); [2] Chakraborty et al., J. Phys.: Conf. Series \textbf{875}, 072002 (2017); [3] Choi et al., Phys. Rev. A \textbf{95}, 023404 (2017); [4] Fojon et al., Phys. Rev. A \textbf{54}, 4923 (1996). [Preview Abstract] 

M01.00034: Measurement of Vibrational Feshbach Resonances Mediated by Nondipole PositronMolecule Interactions. J. R. Danielson, M. R. Natisin, C. M. Surko, A. R. Swann, G. F. Gribakin Experiments have shown that lowenergy (sub eV) annihilation spectra of positrons on molecules are typically dominated by relatively sharp features that have been identified as vibrational Feshbach resonances (VFR) involving fundamental modes. A theory by Gribakin and Lee,\footnote{Gribakin and Lee, Phys. Rev. Lett. {\bf 97}, 193201 (2006).} is successful in describing quantitatively annihilation spectra for several small molecules, where they are dominated by {\it dipoleactive} fundamental modes. Presented here are measurements of positronmolecule annihilation using a recently developed cryogenic positron beam with significantly improved energy resolution.\footnote{Natisin, et. al., Phys. Rev. Lett. {\bf 119}, 113402 (2017).} Data for 1,2transdichloroethylene and tetrachloroethylene show clear signatures of a resonance at the location of {\it nondipoleactive} CC stretch modes. The magnitudes of these resonances are consistent with a simple model that predicts resonances due to {\it quadrupole} coupling. This work provides evidence that positronmolecule bound states can be populated by {\it nondipole} interactions. Further implications of this work will be discussed. [Preview Abstract] 

M01.00035: Elastic scattering of ${\it o}$Ps by $\text{H}_2$ at low energies J.Y. Zhang, M.S. Wu, Y. Qian, X. Gao, Y.J. Yang, K. Varga, Z.C. Yan, U. Schwingenschlogl We investigate the lowenergy scattering of orthpositronium by $\text{H}_2$ from first principles of quantum mechanics using explicitly correlated Gaussians as basis functions. Using the confined variational method, we obtain highly accurate $S$wave phase shifts and pickoff annihilation parameters for different incident momenta. With the leastsquares fit of these data to the effectiverange theory expansions, we determine the $S$wave scattering length $A_s = 2.09 a_0$ and the zeroenergy value of pickoff annihilation parameters $^1\!\text{Z}_\text{eff}=0.186$. The present value of $^1\!\text{Z}_\text{eff}$ is in good agreement with the experimental values $0.194(4)$ (PRA ${\textbf 20}$, 347 (1979)) and $0.186(1)$ (JPB ${\textbf 16}$, 4065 (1983)). In addition, the present value of $S$wave scattering length $2.09a_0$ agrees well with the experimental value $2.1(2)a_0$ estimated with the experimental momentumtransfer cross section (JPB ${\textbf 36}$, 4191 (2003)). [Preview Abstract] 

M01.00036: WannierBloch approach to localization in highorder harmonic generation in solids Alexis Chacon, Edyta Osika, Noslen Suarez, Lisa Ortmann, Jose Antonio PerezHernandez, Bartlomiej Szafran, Marcelo F Ciappina, Fernando Sols, Alexandra Landsman, Maciej Lewenstein The emerging field of highorder harmonic generation (HHG) in solids opens new avenues in attosecond science to interrogate the nature of the electronhole structure and dynamics. It is well known that harmonic emission in the gas phase is a ``spatially localized" process. However, in solids that question is still of intense debate, i.e. what the degree of localization is and how to measure it. In this contribution by isolating nearestneighbor harmonic contribution, we develop a model where a connection between the wellunderstood HHG in atom to the HHG in solids is presented. It is done by means of a treatment of the electron wavefunction of the lattice structure as a set of Wannier states in the valance band and Bloch functions in the conduction one. [Preview Abstract] 

M01.00037: Characterization of induced nanoplasmonic fields near Au nanoellipsoids: a classical trajectory approach Erfan Saydanzad, Jianxiong Li, Uwe Thumm Attosecond streaking spectroscopy is a powerful method for studying the dynamics of photoelectronic processes. We have extended our numerical simulations for metal nanospheres [13] to ellipsoidal Au nanoparticles. By sampling over classical photoelectron trajectories, we simulated streaked photoelectron energy spectra as a function of the time delay between the extreme ultraviolet and assisting infrared (or visible) streaking laser pulses. Our calculated streaking spectra show a pronounced shape dependence at equal nanoellisoid volume, even after averaging over the nanoparticle orientations, which can be characterized by the delaydependent energy variance of streaking traces. [1] E. Saydanzad, J. Li, and U. Thumm, Phys. Rev. A 95, 053406 (2017). [2] J. Li, E. Saydanzad, and U. Thumm, Phys. Rev. A \textbf{94}, 051401(R) (2016); Phys. Rev. A \textbf{95}, 043423 (2017). [3] E. Saydanzad, J. Li, and U. Thumm, in preparation. [Preview Abstract] 

M01.00038: Macroscopic HHG simulations using microscopic TDSE calculations Ran Reiff, Andreas Becker, Agnieszka JaronBecker Modelling high harmonic generation from a gas jet or other macroscopic collection of atoms requires combining microscopic solution of the time dependent Schrodinger equation (TDSE) and simulation of the response of billions of atoms. We present a method of interpolation of TDSE results as a function of laser intensity at a given wavelength. These (precalculated) data are then used in simulations of the macroscopic propagation of the high harmonic signals using the discrete dipole approximation. Results for different atoms, represented via singleactive electron potentials, and driver wavelengths will be presented. [Preview Abstract] 

M01.00039: Determining the branching ratios of sitespecific water and hydronium formation from ethanol T. Severt, K. Borne, F. Ziaee, B. Jochim, P. Feizollah, B. Kaderiya, P. Kanaka Raju, K. D. Carnes, D. Rolles, A. Rudenko, I. BenItzhak, N. Ekanayake, M. Nairat, N. P. Weingartz, B. M. Farris, B. G. Levine, J. E. Jackson, M. Dantus In ethanol, water and hydronium cations may be formed by single or double hydrogen migration, respectively. Due to the geometric structure of ethanol, the migrating hydrogens can originate from either the CH$_3$ or CH$_2$ sites to form bonds with the OH moiety. To determine the sitespecific branching ratios of water and hydronium formation induced by an ultrafast intense laser field, we employ coincidence momentum imaging to measure the fragmentation of a variety of isotopologues of ethanol. We also briefly highlight how this method can be used to determine the sitespecific branching ratios of H$_2^+$ and H$_3^+$ formation. [Preview Abstract] 

M01.00040: Native frames: Analyzing threebody fragmentation of CO$_2$ Peyman Feizollah, T. Severt, Bethany Jochim, Ben Berry, Kanaka Raju P., M. Zohrabi, Jyoti Rajput, U. Ablikim, B. Kaderiya, Farzaneh Ziaee, A. Rudenko, D. Rolles, K. D. Carnes, B. D. Esry, I. BenItzhak Threebody fragmentation of molecules, and methods to analyze and interpret the results, have drawn much attention during the past several years. In this work, we employ the novel nativeframes method to analyze and understand threebody fragmentation processes in CO$_2$. In our measurements, 3D momentum imaging is used to study different fragmentation channels resulting from the interaction of intense laser pulses with polyatomic molecules such as CO$_2$ and its ions . We demonstrate that, using the nativeframes method, one gains access to detailed information about the fragmentation process by completely separating the concerted and sequential breakup contributions. We present the branching ratios of different competing processes as well as the angular dependence of the breakup channels. Also, the kinetic energy release in the fragmentation process is used to identify the states, of the parent or intermediate molecule, that are involved in the breakup. [Preview Abstract] 

M01.00041: Timeresolved twophotontwopath photoemission spectroscopy of Ag(111) and Au(111) surfaces Marcelo Ambrosio, Uwe Thumm While timeresolved photoelectron spectra address transient collective and singleelectron effects in solids with unprecedented resolution [14], their interpretation is challenging and requires numerical modeling. We quantummechanically modeled twophotontwopath photoemission spectra from metal surfaces, including Fresnel transmission and reflection of the incident IR pulse at the surface in terms of generalized Volkov final states, which we find in numerical applications to Ag(111) and Au(111) surfaces to significantly influence the photoemission process [4]. To compare [5] with measured RABBITT (reconstruction of attosecond beating by interference of twophoton transitions) spectra [1], we phenomenologically added pulsedelayindependent contributions of secondary XUV and IR photoelectrons and adjusted surfaceelectronicstructure parameters to recently measured energyresolved synchrotronradiation photoemission spectra [6] [1] R. Locher \textit{et al.}, Optica \textbf{2}, 405 (2015). [2] Z. Tao \textit{et al.}, Science \textbf{353}, 62 (2016). [3] M. Lucchini \textit{et al.}, Phys. Rev. Lett. \textbf{115}, 137401 (2015). [4] M. J. Ambrosio and U. Thumm, Phys. Rev. A \textbf{94}, 063424 (2016); Phys. Rev. A \textbf{96}, 051403 (2017). [5] M. J. Ambrosio and U. Thumm, in preparation. [6] F. Roth \textit{et al.}, J. Electron. Spectrosc. Relat. Phenom., in press (2017). [Preview Abstract] 

M01.00042: Electronic localization effects in timeresolved photoelectron spectroscopy from Cu(111) surfaces Marcelo Ambrosio, Uwe Thumm Attosecond photoelectron spectroscopy allows the observation of electronic processes with attosecond time resolution (1 as $=$ 10$^{\mathrm{18}}$ s). Recent applications to solid surfaces and isolated nanoparticles [15] are starting to allow the scrutiny of electronic dynamics in matter with added spatial resolution, probing the electronic band structure and dielectric response in nanoplasmonically enhanced lightinduced [6]. Based on a quantummechanical model for photoelectron emission by an attosecond pulse train from the $d$band of a Cu(111) surface into a delayed assisting laser pulse [5], we calculate twopathway twophoton interferograms as functions of the photoelectron energy and pulse delay [7]. Our results characterize the dependence of photoelectron interferograms on the surface electronic structure and photoelectron transport and agree with the experimental spectra in Ref. [4]. [1] U. Thumm \textit{et al.}, Fundamental of Photonics and Physics, Vol. 1, (Wiley, New York, 2015). [2] R. Locher \textit{et al.}, Optica \textbf{2}, 405 (2015). [3] Z. Tao \textit{et al.}, Science \textbf{353}, 62 (2016). [4] M. Lucchini \textit{et al.}, Phys. Rev. Lett. \textbf{115}, 137401 (2015). [5] M. J. Ambrosio and U. Thumm, Phys. Rev. A \textbf{94}, 063424 (2016). [6] J. Li \textit{et al.}, Phys. Rev. A \textbf{95}, 043423 (2017). [7] M. J. Ambrosio and U. Thumm, Phys. Rev. A \textbf{96}, 051403 (2017). [Preview Abstract] 

M01.00043: Relative Delay among Br and Kr 4p, 4s, and 3d Photoionization Hannah Killian, Maia Magrakvelidze, Himadri Chakraborty We study the photoionization WignerSmith (WS) time delays and dipole quantum phases of bromine and krypton using KohnSham timedependent local density approximation (TDLDA) [1] with the Leeuwen and Baerends exchangecorrelation functional [2]. The focus of the investigation is electron correlations effects on the absolute as well as relative delays in emissions from both valence 4$p$ and 4$s$, and core 3$d$ levels. Particular emphasis is paid to unravel the role of correlations to induce structures in the delay as a function of energy at resonances and Cooper minima. The results should encourage attosecond measurements of iodine photoemission and probe the WStemporal landscape of an openshell atomic system. [1] Magrakvelidze et al, Phys. Rev. A \textbf{91}, 063415 (2015). [2] van Leeuwen et al, Phys. Rev. A 49, 2421 (1994). [Preview Abstract] 

M01.00044: Longitudinal Momentum of Electron at the Tunneling Exit Tao Li, Xu Wang The longitudinal momentum of the electron at the exit of tunneling ionization is an important parameter to make sense of the tunneling process. It is usually assumed to be zero, but recent experiments show that some nonzero values must be included in order to explain the measured electron spectra. Here we try to shed some light on this topic by numerically solving the timeindependent Schr\"{o}dinger equation(TISE) and the timedependent Schr\"{o}dinger equation(TDSE) of an atom in strong laser fields. We look for longitudinal momentum, defined as the derivative of the phase of the wave function, at the position of the tunneling exit. We find that the longitudinal momentum is nonzero even in the adiabatic (static) limit. And nonadiabaticity may further increase this momentum, especially for weak laser field strengths. [Preview Abstract] 

M01.00045: Decay of an autoionizing Intruder State resolved in time Jeremy Ponsot, Nicolas Douguet, Bejan Ghomashi, Luca Argenti Polyelectronic atoms can exhibit autoionizing Rydberg series whose quantum defects and reduced widths change sharply with energy, due to the interaction between the main configurations of the series and a different configuration, energetically close to the series limit, known as intruder states. Modern timeresolved photoelectron spectroscopies offer the chance to resolve the decay of such intruder states in time. Here, the evolution of an intruder state is studied by solving the timedependent Schroedinger equation on a grid for a 1D model with zerorange potentials. The intruder state, excited from the ground state by a short light pulse, decays first to a transientlybound wavepacket, formed by several terms of the autoionizing series, and subsequently to the continuum. The characteristic times of these two stages of the decay are recognized in the dipoletransition amplitude from the ground state, which is analytically known. Preliminary results for the decay of intruder states in realistic atomic targets~[1,2] will also be presented. [1] L. Argenti et al., J. Phys. B 39, 2773 (2006). [2] K. Schulz et al., Phys. Rev. A 54, 3095 (1996). [Preview Abstract] 

M01.00046: Resonant Anisotropic Emission in Checkerboard RABBITT Spectroscopy Bejan Ghomashi, Nicolas Douguet, Luca Argenti A variant of RABBITT pumpprobe spectroscopy [1] in which the attosecond pulse train comprises both even and odd harmonics of the fundamental IR probe frequency [2] is explored to measure timeresolved photoelectron emission in systems that exhibit autoionizing states. It is shown that the group delay of both onephoton and twophoton resonant transitions is directly encoded in the energyresolved photoelectron anisotropy as a function of the pumpprobe timedelay. This principle is illustrated for a 1D model with symmetric zerorange potentials that supports both bound states and shape resonances. The outcome of a RABBITT experiment for this system is computed analytically, using secondorder perturbation theory [3], as well as numerically, by solving the timedependent Schr\"{o}dinger equation on a grid. [1] P. M. Paul et al., Science, 292, 1689 (2001). [2] G. Laurent et al., Phys. Rev. Lett. 109, 083001 (2012). [3] \'{A}. Jim\'{e}nez Gal\'{a}n et al., Phys. Rev. Lett. 113, 263001 (2014). [Preview Abstract] 

M01.00047: Loss of coherence in atomic ionization with attosecond pulses Saad Mehmood, Coleman Cariker, Tor Kjellsson, Eva Lindroth, Luca Argenti The ions that emerge from the ionization of an atomic target with short light pulses are only partly coherent, since the possible ionic states are entangled with different photoelectron wavepackets [1]. Here we use a newly developed ab initio program that solves the timedependent Schroedinger equation for polyelectronic atoms, to study how the parameters of sequences of short ionizing pulses affect the residual ion coherence for helium and argon targets. The program originates from the merge between a timedependent closecoupling code for twoactiveelectron atoms [2] and the Stock Bspline closecoupling structure program [3]. [1] S Pabst et al., Phys. Rev. Lett. 106, 053003 (2011). [2] L Argenti and E Lindroth, Phys. Rev. Lett. 105, 053002 (2010). [3] T Carette et al., Phys. Rev. A 87, 023420 (2013). [Preview Abstract] 

M01.00048: Timedependent photoionization of atomic and molecular systems using a hybrid Gaussian and Finiteelements discrete variable representation basis set Nicolas Douguet, Heman Gharibnejad, Barry Schneider, Luca Argenti We present preliminary results of a computational method to solve the timedependent Schr\"{o}dinger equation for an atomic or molecular system interacting with a short laser pulse. The multielectron system is described by combining the MESA (Molecular Electronic Structure Applications) quantum chemistry package with Gaussians functions and the FiniteElement Discrete Variable Representation (FEDVR) [1] basis. The matrix elements between boundfree and freefree functions are computed via the accurate 3dimensional adaptive quadrature grid of Rescigno and McCurdy [2]. The method assumes a separable representation [2] and neglects exchange interactions involving FEDVR functions. The hybrid basis will be used to propagate an electronic wavepacket under the action of a short pulse. [1] T. N. Rescigno and C. W. McCurdy, Phys. Rev. A {\bf 62} 032706 (2000), [2] C. W. McCurdy and T. N. Rescigno, Phys. Rev. A {\bf 39} 4487 (1989). [Preview Abstract] 

M01.00049: Binary gas mixture in a high speed channel Dr. Sahadev Pradhan The viscous, compressible flow in a 2D wallbounded channel, with bottom wall moving in? the positive $x$direction, simulated using the direct simulation Monte Carlo (DSMC) method,? has been used as a test bed for examining different aspects of flow phenomenon and separation performance of a binary gas mixture at Mach number \textit{Ma }$=$\textit{ (U\textunderscore w / }$\backslash $\textit{sqrt(}$\gamma $\textit{ k\textunderscore B T\textunderscore w /m)?) }in the range\textit{0.1 \textless Ma \textless 30}, and Knudsen number \textit{Kn }$=$\textit{ 1/(}$\backslash $\textit{sqrt(2) }$\pi $\textit{ d\textasciicircum 2 n\textunderscore d H)}in the range? \textit{.1 \textless Kn \textless 10}. The generalized? analytical model is formulated which includes the fifth order differential equation for the? boundary layer at the channel wall in terms of master potential ($\chi )$, which is derived? from the equations of motion in a 2D rectangular $(x  y)$coordinate. The starting point? of the analytical model is the NavierStokes, mass, momentum and energy conservation? equations in the $(x  y)$coordinate, where $x$and $y$are the streamwise? and wallnormal directions, respectively. The linearization approximation is used ((Pradhan {\&} Kumaran\textit{, J. Fluid Mech }); (Kumaran {\&} Pradhan, \textit{J. Fluid Mech })), where the equations of motion are truncated at linear order in the velocity and pressure perturbations to the base flow, which is anisothermal compressible Couette flow. Additional assumptions in the? analytical model include high aspect ratio \textit{(L \textgreater \textgreater H)}, constant temperature in the base state (isothermal condition), and low? Reynolds number (laminar flow). The analytical solutionsare compared with direct simulation Monte Carlo (DSMC) simulations and found good agreement (with a difference of less than 10{\%}), provided the boundary conditions are accurately incorporated in the analytical solution. [Preview Abstract] 

M01.00050: Femtosecond TimeResolved Energy Transfer Dynamics in Excited Doped Helium Nanodroplets Catherine Saladrigas, Stephen R. Leone, Daniel M. Neumark, Oliver Gessner Helium nanodroplets offer superb possibilities to study hostdopant energy and charge transfer processes in complex systems approaching macroscopic dimensions. When electronically excited, the droplet can undergo a variety of relaxation mechanisms. We are interested in studying the energy transfer processes that occur when a dopant atom is introduced into an excited droplet environment. In a previous, static experiment, energy transfer to noble gas dopants was observed. At sufficiently high droplet excitation energies, the energy transfer results in indirect ionization of the dopant. We are preparing a complimentary time resolved experiment to observe the timescales of the energy transfer processes and learn how they compete with internal droplet relaxation mechanisms. Using a high harmonic generated femtosecond XUV pulse to electronically excite the droplet and a femtosecond UV probe pulse to deplete the energy transfer signal, we can detect the photoelectrons produced from the energy transfer with velocity map imaging as a function of pumpprobe time delay. Based on the time it takes for signals to rise back in after an initial depletion, we can gain information on the timescales of energy transfer. Preliminary results and future directions will be presented. [Preview Abstract] 

M01.00051: Characterization of a UV prism compressor for UVIR pumpprobe experiments Kurtis Borne, Farzaneh Ziaee, Kanaka Raju Pandiri, Balram Kaderiya, Yubaraj Malakar, Travis Severt, Itzik BenItzhak, Artem Rudenko, Daniel Rolles, Ruaridh Forbes We report on the characterization of a setup for UVIR pumpprobe experiments on gasphase molecules using thirdharmonic generation (THG) of a Ti:Sapphire laser. Using a Calcium Fluoride prism compressor, we have been able to reduce the UV (266 nm) pulse duration in the interaction region from 100 fs to \textless 50 fs. We measure these pulse durations via crosscorrelation of the UV pulse with the fundamental IR using a differencefrequency generation (DFG) crystal, as well as a crosscorrelation in Ar gas using a cold target recoil ion momentum spectrometer (COLTRIMS). Results of the pulse characterization will be presented along with data on the timedependent UVinduced photodissociation of CH$_{\mathrm{3}}$I. [Preview Abstract] 

M01.00052: Adaptive strongfield control of vibrational population in NO$^{2+}$ E. Wells, O. Voznyuk, Adam Broin, R. Averin, Bethany Jochim, M. Zohrabi, K.D. Carnes, I. BenItzhak An adaptive closedloop system incorporating coincidence timeofflight feedback is used to determine the optimal intense laser pulse shapes for manipulating the branching ratio of NO$^{2+}$. Selection between the NO$^{2+}$ and N$^+$ + O$^+$ final products requires control of the vibrational population distribution in the transient NO$^{2+}$, with $v \ge$ 12 of the NO$^{2+}$ X $^2\Sigma^+$ state dissociating to N$^+$ + O$^+$. The ability to both suppress and enhance NO$^{2+}$ relative to N$^+$ + O$^+$ is observed, with the effectiveness of shaped pulses surpassing near Fourier transformlimited pulses by about an order of magnitude in each direction, depending on the pulse energy. The control is subsequently investigated using velocity map imaging, identifying plausible dissociation pathways leading to N$^+$ + O$^+$. Combining this analysis with a welldefined control objective supports the conclusion that the primary control mechanism involves selectively populating nondissociative NO$^{2+}$ vibrational states. The optimized pulse complexity increases as the laser intensity increases, complicating determination of the molecular dynamics underlying this control. [Preview Abstract] 

M01.00053: Creating photonic fractional quantum Hall states and braiding anyons Shovan Dutta, Erich Mueller We present and analyze a protocol in which polaritons in a noncoplanar optical cavity form fractional quantum Hall states. We model the formation of these states and present techniques for subsequently creating anyons and measuring their fractional exchange statistics. In this protocol, we use a rapid adiabatic passage scheme to sequentially add polaritons to the system, such that the system is coherently driven from $n$ to $n+1$particle Laughlin states. Quasiholes are created by slowly moving local pinning potentials in from outside the cloud. They are braided by dragging the pinning centers around one another and the resulting phases are measured interferometrically. The most technically challenging issue with implementing our procedure is that maintaining adiabaticity and coherence requires that the twoparticle interaction energy $V_0$ is sufficiently large compared to the singlepolariton decay rate $\gamma$, $V_0 /\gamma \gg 10 N^2 \ln N$, where $N$ is the number of particles in the target state. While this condition is very demanding for presentday experiments where $V_0 /\gamma\sim 50$, our protocol presents a significant advance over the existing protocols in the literature. [Preview Abstract] 

M01.00054: Transfer of Orbital Angular Momentum from Laguerre Gausian Beam to Trapped Rydberg Atoms Koushik Mukherjee, Pradip Mondal, Sonjoy Majumder, Bimalendu Dev The transfer mechanism of the orbital angular momenta (OAM) of light to trapped groundstate atoms under paraxial approximation is well known. Here, we show the formalism of transferring optical OAM, under paraxial approximation, from a LaguerreGaussian(LG) beam to trapped Rydberg atoms. Our derivation shows that optical OAM can be directly transferred or shared to the electronic state of Rydberg atom at the level of dipole transitions. The Gaussian part of the profile of the LG beam, which is generally neglected, is found to have an important effect on the OAM transfer to the Rydberg atoms. Our numerical calculations using Rydberg Rubidium atoms trapped in a harmonic potential show that the otherwise forbidden transitions become sufficiently probable. [Preview Abstract] 

M01.00055: Searching for axion stars with a global network of optical atomic magnetometers C. A. Palm, A. Penaflor, A. Guest, D. F. Jackson Kimball The GNOME collaboration (the Global Network of Optical Magnetometers to search for Exotic physics) is using a worldwide network of optical atomic magnetometers to search for correlated transient signals heralding new physics [Pospelov et al., Phys. Rev. Lett. {\textbf{110}}, 021803 (2013)]. Potential search targets for the GNOME include compact darkmatter objects such as axion stars [Jackson Kimball et al., arxiv:1710.04323]. We discuss the particular implementation and characteristics of the Hayward GNOME magnetometer and analyze prospects for detecting a terrestrial encounter with an axion star by the GNOME. [Preview Abstract] 

M01.00056: Isotope shift in the search for the nuclear island of stability and new physics Anna Viatkina, Victor Flambaum, Amy Geddes We derive a meanfield relativistic formula for the isotope shift of an electronic energy level with arbitrary angular momentum. We use this formula to predict the spectra of superheavy metastable neutronrich isotopes belonging to the hypothetical island of stability. These results may be applied to the search for such superheavy atoms in astrophysical spectra. In addition, it has been recently suggested to use measurements of King plot nonlinearity in a search for hypothetical new light bosons. However, one can find nonlinear corrections to the King plot appearing already in the Standard Model framework. We investigate contributions to the nonlinearity arising from relativistic effects in the isotope field shift, the nuclear polarizability, and manybody effects. It is found that the nuclearpolarizability term can lead to significant deviation of the King plot from linearity. We then proceed with a rough analytical estimate of the nonlinearity arising solely from the effect of a hypothetical scalar boson. Our predictions place theoretical sensitivity limits on the search for new interactions and should help to identify the most suitable atoms for corresponding experiments. [Preview Abstract] 

M01.00057: Precise rotation angle measurement $8.44$ dB beyond the standard quantum limit Yiquan Zou, LingNa Wu, Qi Liu, XinYu Luo, ShuaiFeng Guo, JiaHao Cao, Meng Khoon Tey, Li You We demonstrate an interferometric measurement precision beyond the standard quantum limit (SQL) using a spin1 Dicke state containing more than 10000 entangled atoms. The high quality Dicke state is deterministically generated through controlled quantum phase transition in a BoseEinstein condensate of ground state $F=1$ $^{87}$Rb atoms. Compared to the twinFock state (spin$1/2$ Dicke state) we reported earlier[1], the spin1 Dicke state allows for a higher precision using SU(2) threemode interferometry, which couples the three Zeeman states $F=1,m_F=0,\pm1\rangle$ symmetrically using a resonant radiofrequency field. We achieve a rotation angle measurement sensitivity $8.44$dB below the twomode SQL of $1/\sqrt N$ and $2.42$dB below the threemode SQL of $1/(2\sqrt N)$. \\ \\ {[1] Luo, X. Y., Zou, Y. Q., Wu, L. N., Liu, Q., Han, M. F., Tey, M. K., You, L. Science, {\bf 355}, 620 (2017).} [Preview Abstract] 

M01.00058: Standard Frequency Reference Error Evaluation for a Transportable Atom Gravimeter Jiafeng Cui, Yaoyao Xu, Xiaochun Duan, Kun Qi, Lele Chen, Dekai Mao Based on our former laboratoryconfined atom gravimeters, we developed our first generation of the mobile atom gravimeter Systematic errors on this apparatus have been evaluated to give the absolute gravity value g. A new method to calibrate the standard frequency reference for the atom gravimeter by the instrument itself is described here which has potential application for field measurement. Atomic gravimeters are based on twophoton stimulated Raman transitions The frequency difference at the atoms hyperfine transition is driven by stable wave generator which is further referenced to a commercial 10MHz frequency standard. Any deviation from 10MHz could cause a gravity measurement error. Inspired by microwave atomic fountain clock, the calibration is done by compare the wave generator output frequency to the atomic transition through Ramsey interaction and then inverse analyze the frequency standard deviation. The Ramsey microwave cavity is replaced by the Raman laser pulses which is more adaptive to our present setup for assessing systematic error for g value The standard frequency reference is measured to a relative precision of 1E10, and the corresponding error is constrained below 1 µGal in our gravity measurement. [Preview Abstract] 

M01.00059: Measurement of the Rydberg constant using highly excited positronium atoms David Cassidy Exciting positronium (Ps) atoms to Rydberg states effectively turns off the annihilation process and therefore significantly increases their lifetimes. Since Rydberg atoms may have large electric dipole moments, optically exciting Ps atoms also makes it possible to steer, decelerate, and even trap them using inhomogeneous electric fields. Here I will report the first demonstration of Stark manipulation of Ps atoms, and discuss future applications, including precision spectroscopy of Rydberg Ps levels. By slowing down Rydberg Ps atoms and exciting them to circular states it may be possible to perform optical transitions and measure the Rydberg constant at a useful level of precision. Useful in this context means it could contribute to the ongoing proton radius problem. A measurement of Ps would be a useful addition to other work in this area since the protonfree Ps system can offer a ``pure'' measurement of the Rydberg constant. [Preview Abstract] 

M01.00060: Dualaxis pipulse SERF magnetometer for biomedical applications Elena Zhivun, Michael Bulatowicz, Alexander Hryciuk, Thad Walker We present a new twoaxis vector SERF magnetometer with suppressed technical 1/f noise on both sensitive axes. It reaches a probe sensitivity of 2\,fT$\times$Hz$^{1/2}$ ($\hat{x}$) and 8\,fT$\times$Hz$^{1/2}$ ($\hat{y}$) at 10\,mHz, outperforming the DC SERF magnetometer in the same setup (27\,fT$\times$Hz$^{1/2}$). The lowest probe noise of 0.7\,fT$\times$Hz$^{1/2}$ ($\hat{x}$) and 1.5\,fT$\times$Hz$^{1/2}$ ($\hat{y}$) is reached at 10\,Hz, comparable to the DC SERF probe noise at the same frequency (0.3\,fT$\times$Hz$^{1/2}$). The magnetometer operates by applying a superposition of a DC offset field and a $\pi$pulse comb while remaining in the SERF regime. The resulting alkali precession signals for $B_x$ and $B_y$ fields are orthogonal to each other and synchronous to the pulse repetition rate. [Preview Abstract] 

M01.00061: Magnetic gradiometer array operating in closedloop mode Nicholas Nardelli, Abigail Perry, Sean Krzyzewski, Branislav Korenko, Svenja Knappe We report on the development of a multichannel magnetic imaging system consisting of 24 gradiometers for use in magnetoencephalography. Each gradiometer consists of two chipscale atomic magnetometers separated by 2 cm, operating in the spinexchange relaxation free (SERF) regime. They share a laser beam for pumping and probing to reduce the common mode noise from the laser, and atomic vapor pressure is independently controlled by optically heating at telecom wavelength. Most SERF atomic magnetometers operate in openloop mode but we operate our system in closedloop mode where we maintain the magnetometer at zero field by feeding back the magnetic error signal onto a set of coils. This increases the stability of the system as well as increasing the commonmode rejection of the gradiometer. Operating in closedloop also increases the dynamic sensing range since the feedback keeps the magnetometers functioning within the linear range of the dispersion. Working simultaneously, the gradiometers achieve sensitivities ranging from 10  13 fT/Hz\textasciicircum 1/2 and are able to function in the presence of background fields up to 70 nT. We are investigating the role that crosstalk plays in limiting the sensitivity of the system which may limit the possible gradiometer density [Preview Abstract] 

M01.00062: Sensing the Local Charge and Strain Environment of Nitrogen Vacancy Centers in Diamond Prabudhya Bhattacharyya, Satcher Hsieh, Thomas Mittiga, Bryce Korbin, Francisco Machado, Chong Zu, Thomas Smart, Soonwon Choi, Viktor Struzhkin, Raymond Jeanloz, Norman Yao The Nitrogen Vacancy (NV) center in diamond has emerged as a promising candidate for nanoscale sensing, in part, because of its sensitivity to a myriad of external parameters. However, coupling to local \emph{internal} strain and electric fields (i.e. in the diamond host) can suppress this sensitivity to external signals. This is especially important in high density ensembles, where one leverages spin correlations to perform enhanced spectroscopy. We demonstrate that in such samples, spectral features typically attributed to internal strain in fact result from electric fields originating from local charged defects. We distinguish between the effects of strain and electric fields by using diamond anvil cells to characterize the elastic response of NV centers in the gigapascal regime. Under these conditions, we investigate the charge dynamics of the NV center and reconstruct the complete strain tensor within the anvil cell. [Preview Abstract] 

M01.00063: Atombased RF field measurement using allinfrared laser fields Eric Peterson, Nithiwadee Thaicharoen, Kaitlin Moore, David Anderson, Robert Powel, Georg Raithel Atombased sensors for electric fields could serve as an atomic measurement standard for field quantities, and could substantially expand the capabilities and fields of use of existing antenna technologies. Recently, a rapidly expanding body of research has shown that Rydberg electromagnetically induced transparency (EIT) in atomic vapors presents a novel venue to measuring electric fields, over a broad range of frequencies and strengths. Many of these works employ a 780nm probe laser and a 480nm coupling laser. Motivated by the needs the development of commercially viable electricfield sensors might present, we investigate a 3photon Rydberg EIT scheme which uses only inexpensive diode lasers. The dependence of the 3photon EIT signals on laser propagation directions and dressingbeam detuning is characterized. Further, the 3photon optical technique has performed well in initial tests to measure microwave electric fields. [Preview Abstract] 

M01.00064: Local cooling and control of a 2D nuclear spin lattice using NV centers in diamond Tamara Sumarac, Elana Urbach, Helena Knowles, Javier SanchezYamagishi, Igor Lovchinsky, Soonwon Choi, Renate Landig, Alexei Bylinskii, Hongkun Park, Mikhail Lukin ~Two dimensional materials can provide a regular nuclear spin lattice, which makes them an excellent platform for studying interacting 2d spin dynamics. Traditional NMR techniques are not sensitive enough to measure small sample volumes of thin materials. Nitrogen vacancy (NV) centers in diamond can act as nanoscale magnetic field sensors with the ability to measure magnetic field created by very few nuclear spins. This makes the NV center an ideal probe for studying nuclear spin dynamics in 2d materials. In this experiment we use an NV center combined with an external radio frequency field to locally initialize, control and readout nuclear spin states inside hexagonal boron nitride (hBN), with a goal of developing a room temperature platform for studying manybody dynamics. [Preview Abstract] 

M01.00065: ABSTRACT WITHDRAWN 

M01.00066: Probe Detuning Dependence of Free Induction Decay in Nuclear Magnetic Resonance Han Seb Moon, Ye Jin Yu, Sungho Min We investigated on the dependence of Free Induction Decay (FID) on the detuning range of probe light in Nuclear Magnetic Resonance (NMR) experiment. Detuning range varies around a resonance frequency of $^{\mathrm{87}}$Rb atom. We use $^{\mathrm{129}}$Xe$^{\mathrm{87}}$Rb gas mixture including N$_{\mathrm{2}}$ and H$_{\mathrm{2}}$ in hot vapor condition. $^{\mathrm{129}}$Xe is a NMR element and $^{\mathrm{87}}$Rb has two roles as mentioned above, one is FID detector as a magnetometer and the other is pumping agent making $^{\mathrm{129}}$Xe hyperpolarized. We measured FID signal by means of detection of optical rotation of probe light detuned to near the resonance region, F$=$1 $\to $ F'$=$2 of $^{\mathrm{87}}$Rb. [Preview Abstract] 

M01.00067: Suppressing Rubidium backpolarization in nuclear spin comagnetometer by radiation trapping assisted depolarization pumping. Kaifeng Zhao, Attaallah Almasi, Mark Limes, Michael Romalis Back polarization of Rb by noble gases causes a systematic error for determining the ratio of precession frequencies in noble gas \textasciicircum 3He\textasciicircum 129Xe comagnetometer that is being developed in our group [1]. We investigate a new active depolarization scheme for Rb atoms using a linearly polarized laser tuned to the Rb D2 transition. The depolarization process is assisted by radiation trapping of D2 light in opticallythick Rb vapor in the absence of N2 quenching gas, which is typically used in most optical pumping experiments. Instead we use hybrid optical pumping with opticallythin K vapor to create a large Rb polarization when needed. We show preliminary results demonstrating active control of Rb polarization over a large dynamic range. [1] M. E. Limes, D. Sheng, and M. V. Romalis, Phys. Rev. Lett. 120, 033401, 2018 [Preview Abstract] 

M01.00068: Atomic combination clocks. Nitzan Akerman, Roee Ozeri The stability and accuracy of atomic clocks are limited by the susceptibility of their internal electronic transitions to external fields. So far atomic clocks were realized using a single species of atom or ion. These atomic species and transitions were selected due to their relative low susceptibility to some environmental perturbations while other properties were typically compromised. We propose to utilize an entangled superposition state of multiple atomic species to form a reference clock frequency. This superposition is selected such that the susceptibilities of the respective transitions, in individual species, destructively interfere leading to improved stability and reduced systematic shifts. One example is the optical quadrupole transitions in a $^{\mathrm{40}}$Ca$^{\mathrm{+}}$  $^{\mathrm{174}}$Yb$^{\mathrm{+}}$ twoion crystal. Here the blackbody radiation shift is reduced to the level of 10$^{\mathrm{19}}$ fractional uncertainty as well as diminishing the susceptibility to first order Zeeman shift while benefiting from the small inherent second order Zeeman shift as compare to species with hyperfine structure. Our method is general and applicable to other combinations as well. It extends the space of possibilities in the search for better atomic reference and thus advances the field of quantum precision metrology and atomic clocks in particular. [Preview Abstract] 

M01.00069: Siteresolved probing of the manybody localization transition in one dimension Julian Leonard, Alexander Lukin, Matthew Rispoli, Robert Schittko, Sooshin Kim, Vedika Khemani, Adam Kaufman, M. Eric Tai, Markus Greiner Manybody localization (MBL) challenges our understanding of thermalization in quantum systems. While nonequilibrium systems usually relax and approach thermal equilibrium, MBL systems remain in a state far from equilibrium. We study this behavior in a BoseHubbard chain that is subject to a controlled disorder potential. We start with a system at unity filling and prepare it in an outofequilibrium state by quenching the tunneling rate from zero a to a finite value. By performing siteresolved full counting statistics, we are able to locally measure the atom number distribution and extract the onsite entropy. We observe the breakdown of thermalization at a critical disorder strength, time dynamics in the thermal, the critical, and the MBL regimes, and an increasing densitydensity correlation length when approaching the critical point. [Preview Abstract] 

M01.00070: Generation of Quantum Dark Solitons via a Localized Driven Impurity Simeon Mistakidis, Garyfallia Katsimiga, Georgios Koutentakis, Panayotis Kevrekidis, Peter Schmelcher The manybody nonequilibrium dynamics of a Bose Einstein Condensate upon a single and/or a periodic passing of a localized material impurity is investigated. The resulting defect formation consisting of gray solitons, occurring only for moderate impurity velocities, is examined comparing the meanfield to a correlated approach. In the former case gray solitons are formed and are found to interact remaining robust throughout the evolution. In contrast within the manybody scenario quantum dark solitons are formed which decay into daughter solitary waves soon after their generation. A multitude of excitations including darkantidark states and domainwall complexes building upon the distinct concurrently populated orbitals is observed. Signatures of these higherlying orbital excitations emerge in the total density, and can be clearly captured by inspecting the one and two body coherences. Utilizing singleshot simulations we demonstrate that the correlated character of the dynamics can be experimentally inferred from both the insitu singleshot images as well as the corresponding variance. Finally, the dependence of the defect characteristics on the interatomic interaction and the particle number is discussed. [Preview Abstract] 

M01.00071: Strongly interacting ytterbium173 in statedependent potentials Nelson Darkwah Oppong, Luis Riegger, Oscar Bettermann, Moritz Hoefer, Immanuel Bloch, Simon Foelling Ytterbium173 features a metastable excited state, the socalled clock state, which we employ to implement twoorbital systems with tunable interactions. The existence of a weakly bound molecular state in the interorbital scattering potential leads to large spinexchange interaction as well as an orbital Feshbach resonance. We probe a strongly interacting Fermi gas of ytterbium173 in the presence of an orbital Feshbach resonance and determine the properties of the interacting system in different external confinements. By adding statedependent mobility to the large spinexchange present in ytterbium173, Kondolike Hamiltonians can be implemented. Our implementation of a statedependent optical lattice localizes excitedstate atoms while groundstate atoms remain mobile. We probe the spinexchange interaction dynamics in this system and find that it can be resonantly tuned in mixed confinement. [Preview Abstract] 

M01.00072: Interactioninduced Bloch Oscillation in a Harmonically Trapped and Fermionized Quantum Gas in One Dimension Lijun Yang, Lihong Zhou, Wei Yi, Xiaoling Cui Motivated by a recent experiment by F. Meinert {\it et al}, arxiv:1608.08200, we study the dynamics of an impurity moving in the background of a harmonically trapped onedimensional Bose gas in the hardcore limit. We show that due to the hidden ``lattice" structure of background bosons, the impurity effectively feels a quasiperiodic potential via impurityboson interactions that can drive the Bloch oscillation under an external force, even in the absence of real lattice potentials. Meanwhile, the inhomogeneous density of trapped bosons imposes an additional harmonic potential to the impurity, resulting in a similar oscillation dynamics but with a different period and amplitude. We show that the sign and strength of the impurityboson coupling can significantly affect the above two potentials in determining the impurity dynamics. [Preview Abstract] 

M01.00073: Longlived twodomain spin structures in a nondegenerate gas Sean Graham, Dorna Niroomand, Robert Ragan, Jeffrey McGuirk We demonstrate that linear differential potentials give rise to longlived longitudinal spin domains with decoupled transverse and longitudinal spin dynamics. At ultracold temperatures, coherent spinrotating interactions lengthen the diffusion time of spin domains in nondegenerate gases. The spin dynamics are further altered by applying linear differential potentials of varying gradients. At specific gradients, we observe stable spin domains for a range of densities and temperature. In the hydrodynamic limit, the measured optimal gradients agree well with a quantum Boltzmann theory. [Preview Abstract] 

M01.00074: Onset of thermalization in a nearly integrable 1D Bose gas Neel Malvania, JeanFelix Riou, Laura Zundel, Joshua Wilson, Lin Xia, David Weiss Because of their many conserved quantities, integrable systems long after a quench are not reliably described by statistical mechanics. A small amount of nonintegrability compromises the conserved quantities, but it is not theoretically clear that this is always sufficient to recover the statistical mechanics result. We attempt to clarify the situation using outofequilibrium 1D Bose gases, excited in socalled quantum Newton's cradles [Kinoshita, T. et al. \textit{Nature} \textbf{440}, 900, (2006)]. The evolution of momentum proceeds due to three mechanisms: spontaneous emission of lattice light, the effect of which we model in a semiclassical Monte Carlo simulation; inelastic 3body loss, for which we measure the collisional energy dependence and then calculate the associated heating; and diffractive (i.e., elastic momentum changing) 3body collisions. Diffractive collisions, which can only arise from nonintegrable terms in the Hamiltonian, can lead to evaporative cooling. By measuring the energy change of the gases as a function of time, we can infer the thermalization rate, which we find to be nonzero. Using 3body inelastic loss as a calibration, we infer the diffractive 3body collision rate from the thermalization rate. We then compare the thermalization rate to theoretical expectations due to the leading nonintegrable term, virtual transverse excitation during a 3body collision [Mazets, I. E. et al. \textit{N. J. Phys.} \textbf{12}, 055023 (2010)], to determine whether proximity to integrability reduces the effectiveness with which diffractive 3body collisions cause thermalization. [Preview Abstract] 

M01.00075: Reflectance of mirrors exposed to a strontium beam John Huckans, Maxim Olshanii The chemical reactivity of strontium, which opacifies vacuum viewports exposed to strontium sources, is a concern for atomic physics experiments where a laser beam counterpropagates relative to a strontium beam. Some experiments use heated sapphire viewports to reduce strontium deposition. Here, we study another approach wherein the laser beam counterpropagates after first reflecting off an invacuum mirror at 45o exposed to the strontium flux. We show that an SiO2protected reflective surface is a solution for strontium depositions up to 1.5μm. A reaction with SiO2 creates a transparent film, maintaining the back surface reflectivity. Deposition on inert sapphire results in much lower reflectance. Our results provide guidance for Zeemandecelerated strontium experiments, and an alternative to heated sapphire viewports. We provide fluxdependent viability estimates. [Preview Abstract] 

M01.00076: DSMC Simulations of High Mach Number TaylorCouette Flow Dr. Sahadev Pradhan The main focus of this work is to characterise the TaylorCouette flow of an ideal gas between two coaxial cylinders at Mach number \textit{Ma }$=$\textit{ (U\textunderscore w / }$\backslash $\textit{sqrt\textbraceleft kb T\textunderscore w / m\textbraceright )}in the range 0.01 \textless Ma \textless , and Knudsen number \textit{Kn }$=$\textit{ (1 / (}$\backslash $\textit{sqrt\textbraceleft 2\textbraceright }$\backslash $\textit{pi d\textasciicircum 2 n\textunderscore d (r\textunderscore 2  r\textunderscore 1))) }in the range 0.001 \textless Kn \textless , using twodimensional (2D) direct simulation Monte Carlo (DSMC) simulations. Here, \textit{r\textunderscore 1}and \textit{r\textunderscore 2}are the radius of inner and outer cylinder respectively, \textit{U\textunderscore w}is the circumferential wall velocity of the inner cylinder, \textit{T\textunderscore w}is the isothermal wall temperature, \textit{n\textunderscore d}is the number density of the gas molecules, $m$and $d$ are the molecular mass and diameter, and \textit{kb}is the Boltzmann constant. The cylindrical surfaces are specified as being diffusely reflecting with the thermal accommodation coefficient equal to one. In the present analysis of high Mach number compressible TaylorCouette flow using DSMC method, wall slip in the temperature and the velocities are found to be significant. Slip occurs because the temperature/velocity of the molecules incident on the wall could be very different from that of the wall, even though the temperature/velocity of the reflected molecules is equal to that of the wall. Due to the high surface speed of the inner cylinder, significant heating of the gas is taking place. The gas temperature increases until the heat transfer to the surface equals the work done in moving the surface. The highest temperature is obtained near the moving surface of the inner cylinder at a radius of about (1.26 r\textunderscore 1). [Preview Abstract] 

M01.00077: Towards simulating manybody quantum dynamics with strontium atoms in optical tweezers. Alexandre Cooper, Jacob Covey, Ivaylo Madjarov, Brian Timar, Emily Qiu, Alexander Baumgärtner, Manuel Endres Ultracold atoms in optical tweezers provide a versatile platform for simulating interacting manybody quantum systems. The ability to assemble single atoms in various spatial configurations, selectively address and control their quantum states, and introduce longrange interactions between them enables studying complex Hamiltonians that are otherwise difficult to access. We report on progress towards creating defectfree arrays of strontium atoms in optical tweezers with tunable Rydberg interactions. Strontium has narrow optical transitions and magic wavelengths, which enable robust cooling, trapping, and coherent manipulation of single atoms. We explore strategies for imaging and cooling atoms in optical tweezers, as well as scaling to larger arrays. We further explore approaches to engineering longrange interactions between strontium atoms via Rydberg states. Our work offers promising research avenues for studying nonequilibrium dynamics of disordered systems, realizing novel states of matter, and simulating spin models with tunable parameters. [Preview Abstract] 

M01.00078: On the question of cooling without spontaneous emission via the bichromatic force Leland Aldridge, David DeMille The optical bichromatic force (BCF) has been experimentally shown to produce forces that exceed the saturated radiative force on both atoms and, recently, molecules. Cooling of atoms with BCF also has been observed, even on time scales shorter than the average time for spontaneous decay. This has been claimed as evidence for cooling without spontaneous emission. A mechanism for such cooling has been proposed, based on entropy exchange between atoms and laser photons. We present results that bear on this claim, from simulations of BCF on an ensemble of twolevel atoms with no spontaneous decay. Our approach uses classical fields and is fully reversible; hence, by construction, atomphoton entropy exchange is absent in our simulations. We show that on sufficiently short time scales, a bounded degree of cooling (positionmomentum phase space compression by a factor of less than two) can occur, due to transfer of entropy into the internal states of the ensemble. On longer time scales, all evidence for cooling disappears unless spontaneous emission is restored in the system. [Preview Abstract] 

M01.00079: Characterization and Suppression of Systematic Errors in the ACME II Measurement of the Electron Electric Dipole Moment Cole Meisenhelder, Daniel G. Ang, David DeMille, John M. Doyle, Gerald Gabrielse, Jonathan Haefner, Nicholas R. Hutzler, Zack Lasner, Brendon R. O'Leary, Cristian D. Panda, Adam D. West, Elizabeth P. West, Xing Wu Measurement of the electron electric dipole moment (eEDM) provides a powerful probe for physics beyond the Standard Model. Currently, ACME II is working towards improving by an order of magnitude upon the 2014 limit on the eEDM of $d_e< 0.9\times10^{28}\ \text{e}\cdot \text{cm}$ . As part of the current experimental generation we have worked to characterize and suppress both the leading sources of systematic error from ACME I and systematics found at our new level of sensitivity. We describe in detail how eEDM mimicking effects can arise from both the coupling of nonreversing electric fields to magnetic field gradients, and the imperfect alignment of laser polarizations. To search for systematic effects we have exaggerated over forty experiment parameters and observed no evidence of a shift in the eEDM measurement. We discuss the techniques that allowed for the suppression of these effects below our current level of statistical uncertainty. [Preview Abstract] 

M01.00080: Optical Pumping Methods for Nuclear $\beta$ Decay John Behr, Erin Broatch, Anya Forestell, James McNeil, Alexandre Gorelov Having completed a nuclear $\beta$ decay asymmetry experiment with the best percentage accuracy ever achieved (0.35\%) [B. Fenker et al., accepted by Phys. Rev. Lett.], we are trying to improve the vector polarization of our lasercooled atoms from our present 99.1 $\pm$ 0.1\%. We cycle on and off a MOT, and optically pump $^{37}$K atoms with trap off. We use circularly polarized light on the 4S$_{1/2}$ $\rightarrow$ 4P$_{1/2}$ transition, using RF sidebands on a diode laser to excite transitions from both F=1 and F=2 ground states. We test techniques with stable $^{41}$K atoms, which have very similar hyperfine splitting to $^{37}$K. Upgrades to improve our systematic uncertainties include: preparing the initial atomic state before optical pumping with faster liquid crystal variable retarders, replacing 0.25 mm thick SiC substrate mirrors in front of the beta detectors with 0.012 mm mylar to minimize $\beta$ straggling, and using a 50 $\mu$s exposure CMOS camera to explore polarization changes across the trapped atom cloud. We must avoid coherent population trapping effects. Diagnostics of the polarization include the time dependence of the excited state population after optical pumping light is applied, probed by measuring fluorescence and by nonresonant photoionization. [Preview Abstract] 

M01.00081: Searching for Dark Matter and Exotic Physics with Atomic Clocks and the GPS Constellation Conner Dailey, Benjamin Roberts, Geoffrey Blewitt, Andrei Derevianko Dark matter (DM) constitutes 85\% of all matter in the Universe, yet conclusive evidence for DM in terrestrial experiments remains elusive. One possibility is that DM is composed from ultralight quantum fields whose selfinteractions lead to the formation of DM objects in the form of stable topological defects. As the Earth moves through the halo of DM objects, interactions with such DM clumps could lead to measurable variations in GPS signals that propagate through the satellite constellation at galactic velocities. We use the network of GPS atomic clocks as a 50,000km aperture DM detector [1]. Recently, we (the GPS.DM collaboration) mined over 16 yr of archival GPS data, and found no evidence for DM in the form of domain walls, which enabled us to improve present limits on certain DMordinary matter coupling strengths by up to 6 orders of magnitude [2]. Here we highlight recent advances made in the GPS.DM collaboration, including (1) a method based on Bayesian analysis that allows us to increase the sensitivity by 2 orders of magnitude, and allows the search for more general DM geometries, e.g. monopoles and strings; (2) our new capability to generate 1s GPS atomic clock data with precision $<$0.1 ns; and (3) new developments in signal detection algorithms. [Preview Abstract] 

M01.00082: Demonstration and Characterization of Scalable Quantum Gate Operations with Trapped Ion Qubits Chao Fang, Stephen Crain, James Joseph, Geert Vrijsen, Rachel Noek, Jungsang Kim The potential for trapped atomic ions to serve as a scalable quantum computing platform relies on the capability to individually address each ion in order to execute a complete set of singlequbit and fully connected twoqubit gates. In this work we perform quantum logic gates by addressing a linear chain of $^{\mathrm{171}}$Yb$+$ ions in a surface trap using two tightly focused laser beams and an elliptical global beam to drive Raman transitions. The two individual addressing beams can be independently steered in two dimensions using tilting microelectromechanical systems (MEMS) mirrors [1]. We present the demonstration of individually addressed singlequbit gates and progress towards M{\o}lmerS{\o}rensen type twoqubit gates. The individual qubit addressing fidelity and crosstalk are characterized. We also present our work towards twoqubit gates between arbitrary pairs of ions in a chain. [1] S. Crain et al., Appl. Phys. Lett. 105, 181115 (2014) [Preview Abstract] 

M01.00083: Impact of surface cleaning and ionelectrode distance on trapped ion motional heating Jonathon Sedlacek, Jules Stuart, Colin Bruzewicz, Robert McConnell, Jeremy Sage, John Chiaverini Motional heating of trapped ions can limit the fidelity of quantum logic operations as well as the accuracy and precision of ionbased atomic clocks. Hence, there is a clear need to characterize and understand the underlying mechanisms of this heating, and ultimately, reduce its magnitude. Here, we perform both \textit{in situ} and \textit{ex situ} plasma cleaning as well as \textit{ex situ} ion milling to reduce the motional heating rates measured using surfaceelectrode ion traps at room temperature. Following surface treatment, we observe a significant change in the electrodetemperature dependence of the measured heating rate. Results showing the ionelectrode distance dependence having $1/d^{4}$ scaling in an uncleaned trap will also be presented. Strategies to mitigate motional heating and constraints put on current theoretical models will be discussed. [Preview Abstract] 

M01.00084: Trapping long ion chains in a cryogenically cooled trap for quantum simulation Harvey Kaplan, Guido Pagano, Wen Lin Tan, Paul Hess, Jessica Hankes, Jiehang Zhang, Antonios Kyprianidis, Patrick Becker, Philip Richerme, Eric Birckelbaw, Micah Hernandez, Yukai Wu, Chris Monroe Long ion chains trapped in a linear Paul trap presents a promising platform for quantum simulation of spin systems. As the number of spins increases, the size of the Hilbert space grows exponentially, and spin systems quickly become intractable to simulate classically, for about 50 spins, where each spin is simulated by an ion. The ion chain lifetime is limited by collisions with background gas, which shortens the lifetime as the number of trapped ions grows. Here we present a new ion trapping system using 171Yb+ in a blade trap in a cryogenic vacuum. The pressure is significantly improved by using differential cryopumping. We present progress with building the apparatus, and measurements to understand the vibrations at the trap, the pressure in the vacuum, and the extent to which the ion crystal spacing can be manipulated. Using a 355 nm frequency comb, we have performed coherent spin manipulations through a Raman process, which will serve as the method for generating long range spinspin couplings. This novel apparatus will enable the simulation of manybody quantum systems that are intractable for classical simulators. [Preview Abstract] 

M01.00085: Ultracold Potassium for Atom chip based Interferometry Shuangli Du, Andrew Rotunno, Andrew Pyle, Seth Aubin We report on progress to cool K to BEC on an atom chip for atom interferometry experiments. We are developing a spindependent atom interferometer based on AC Zeeman traps, which will have enhanced sensitivity and spatial resolution. K are well suited for AC Zeeman force. In particular, $^{\mathrm{41}}$K has a small hyperfine splitting of 254 MHz, which is low enough to enable easy coupling to an atom chip. Also, $^{\mathrm{41}}$K benefits from suppressed sensitivity to magnetic field noise at 24 G and 45 G. Our apparatus uses an atom chip to trap ultracold atoms 100$\mu $m from the chip.This close proximity to the chip ensures that the atoms experience a strong RF and microwave field gradients that are necessary for using AC Zeeman. We have successfully trapped over 3x10$^{\mathrm{6}}$ atoms at 100$\mu $K with a P of 10$^{\mathrm{6}}$. At present, we are working to cool $^{\mathrm{41}}$K directly or with Rb. Once the $^{\mathrm{41}}$K atoms have been cooled to sub$\mu $K levels, or to BEC, then they can be used for interferometry experiments. An interferometer based on $^{\mathrm{41}}$K BEC is a stepping stone towards the creation of a multimode interferometer that can work with ultracold thermal atoms or a degenerated Fermi gas. [Preview Abstract] 

M01.00086: Towards cooling SrF molecules to the ultracold temperature regime Yuqi Zhu, Matthew Steinecker, David DeMille Given the recent demonstration of trapping strontium monofluoride (SrF) molecules in a magnetic quadrupole trap, we have started working towards cooling SrF to the ultracold temperature regime ($T \ll 100 \:\mu$K). Here we present some plans for sympathetic cooling of SrF molecules with cotrapped rubidium (Rb) atoms, and describe progress towards our initial goal of studying interactions of a spinpolarized RbSrF mixture in a magnetic trap. We are also investigating the prospects for Raman sideband cooling (RSC) of SrF in an optical lattice as a way to further cool the molecules without the need for collisions. Preliminary to implementing RSC, the polarizability of ground state SrF has been calculated. We highlight the complexity associated with the anisotropic structure of molecules, and suggest plausible cooling schemes in the presence of this complexity. [Preview Abstract] 

M01.00087: Multichannel square well scattering model for chaotic collisions Nirav Mehta, Christopher Ticknor, Kaden Hazzard A simple manychannel model that consists of squarewell channel potentials with constant couplings inside the well is presented. The number of channels, potential depths, channel couplings and threshold splittings are all tunable parameters, affording enough flexibility to reproduce essential features of chaotic scattering in a simple, semianalytical model. For scattering with one open channel, the position, width and Fano $q$ parameter are extracted for each resonance. The Brody parameter, which characterizes the distribution of energy level spacings and the degree of chaos is calculated. Its behavior as a function of various model parameters is studied. Finally, the effect of an open channel resonance on the background of dense Feshbach resonances is studied. [Preview Abstract] 

M01.00088: Association of single ultracold molecules in optical tweezers Yichao Yu Ultracold polar molecules have longrange, anisotropic, tunable interactions that could be used to study a wide variety of phenomena in quantum manybody physics, quantum information, and quantum simulations. We present a scheme to create fullycontrolled ultracold molecules with singlesite resolution from the ground up, starting with individuallycontrolled atoms. We use optical tweezers to extract and trap single Na and Cs atoms from magnetooptical traps. Both atoms are cooled to their motional ground state in the tweezers using Raman sideband cooling with greater than 92\% probability in order to improve the fidelity of molecule formation. We present details of our approach, as well as our observation of the association of NaCs molecules in the optical tweezers. [Preview Abstract] 

M01.00089: Approaching a final temperature prediction of an ensemble of atoms undergoing cavityassisted cooling in the superradiant regime Ron Pepino, Murray Holland We present results that determine the final temperature of an ensemble of atoms being supercooled in an optical resonator in the parameter regime of superradiance. We verify that one can perform a classical treatment of the light field and still recover the important lasing and superradiant physics.~This treatment yields a set of equations that contain no spin correlations. As a consequence this work ultimately shows that the quantum spinspin correlations between atoms can be safely neglected in computational models in certain parameter regimes. Such a treatment may significantly reduce the size of the Hilbert space and therefore computational complexity needed to compute the final temperature. [Preview Abstract] 

M01.00090: A nearresonant alloptical }$^{\mathrm{\mathbf{6}}}$\textbf{Li atom trap for fewbody experiments Sachin Sharma, B. P. Acharya, A. H. N. C De Silva, N. W. Parris, B. J. Ramsey, Kevin. L. Romans, A. Dorn, Daniel Fischer Momentumresolved scattering experiments with laser cooled targets have been performed with MOTRIMS (MagnetoOptical Trap  Recoil Ion Momentum Spectroscopy) for the last two decades. However, the inhomogeneous magnetic field in a MOT impairs the electron momentum measurement limiting MOTRIMS to ion detection only. The development of MOTReMi (MagnetoOptical Trap Reaction Microscope) made it possible to achieve coincident e$^{\mathrm{}}$ion detection by pulsing the inhomogeneous magnetic field. Nevertheless, using this approach comes at the cost of measurement efficiency and a loss of target density. Here we report on the first realization of a nearresonant alloptical $^{\mathrm{6}}$Li atom trap which does not require an inhomogeneous magnetic field. The temperature and density of the atom cloud were found to be approximately 2 mK and 10$^{\mathrm{9}}$ atoms/cm$^{\mathrm{3}}$ respectively, making it ideal for momentumresolved e$^{\mathrm{}}$ion coincidence experiments. Moreover, this technique only requires minor adjustments to the polarization and geometry of the laser beams, with respect to a conventional MOT configuration, making it applicable in existing MOTRIMS experiments. [Preview Abstract] 

M01.00091: Twisted vortex beams for tailored topological spin textures in spinor BoseEinstein condensates Maitreyi Jayaseelan, Justin T. Schultz, Joseph D. Murphree, Zekai Chen, Nicholas P. Bigelow Optical imprinting techniques have proven useful for creating interesting topological spin textures such as skyrmions, halfquantum vortices, spin monopoles, and nonAbelian vortices in spinor condensates. These protocols manipulate the populations and phases of the atomic spin states via multiphoton Raman processes. However, the AC Stark shift from the radially varying intensities of the optical beams causes an undesirable intensitydependent phase across the cloud, creating a nonuniform twist of the spin texture. One protocol used to correct for this phase twist has used additional optical pulses of a single laser beam with power and detuning set to unwind this extra radial phase. Instead, we investigate singular beams with an additional radial phase profile to compensate for the AC Stark shift that the atomic states accrue during a Raman process. These beams can be created with spatial light modulators, which allow for the control of the azimuthal and radial phase and intensity profiles of optical beams. The intensitydependent phase for the atoms and radial phase of the optical beam can cancel during the Raman process, creating a nontwisted spin texture. [Preview Abstract] 

M01.00092: Work on Improving Precision Laser Spectroscopy of Helium Fine Structure Garnet Cameron, Cory Nook, J.T. Florence, Kadijah Alnasser, David Shiner Various precision techniques are tested when results of experiments on helium fine structure are compared. The results provide a sensitive test of the quantum electrodynamics of the electronelectron interaction, and a test of nuclear fewbody theory using the isotope shift determination of the nuclear size. With planned improvements, an important input to the value of the fine structure constant, $\alpha $, is also possible. Improvements and verification of laser intensity stabilization and reliability have been implemented at better than 100 ppm. Continuing work to improve integration time with higher counts rates is ongoing and requires various modifications to the apparatus and optical techniques, along with refinements in the LabView data collection and system stability. Quantum interference corrections are being calculated and tested as well as data in general to identify limiting sources of uncertainty. [Preview Abstract] 

M01.00093: Prospects for a Third Generation ACME Search for an Electron Electric Dipole Moment Xing Wu, Daniel Ang, Xinyi Chen, David DeMille, John Doyle, Gerald Gabrielse, Jonathan Haefner, Nicholas Hutzler, Zack Lasner, Cole Meisenhelder, Cristian Panda, Adam West, Elizabeth West The observation of an electron electric dipole moment (eEDM) would reveal new sources of timereversal symmetry violation and indicate physics beyond the Standard Model. The most stringent upper limit on the eEDM, \textbar d$_{\mathrm{e}}$\textbar \textless 9.4 x10$^{\mathrm{29}}$~e\textbullet cm, was set by the first generation of the ACME experiment by means of measuring electron spin precession in a beam of thorium monoxide (Science 343 (2014), 269272). Here, we present studies for further improvements to the ACME experiment, with the eventual goal of sensitivity at the 10$^{\mathrm{30}}$ e\textbullet cm level, roughly 1 order of magnitude smaller than the currently running second generation experiment. The methods we discuss focus primarily on improving statistics, and include a magnetic lens to focus the molecular beam and optical cycling to improve detection. [Preview Abstract] 

M01.00094: Rotation Sensing with a Trapped Barium Ion Randy Putnam, Adam West, Wesley Campbell, Paul Hamilton To date, the best rotation sensors are Sagnac interferometers. The associated phase $\Phi$ due to a rotation rate $\vec{\Omega}$ is proportional to the particle energy $E$ and the enclosed area $\vec{A}$ of the interferometer:$\Phi=\frac{4\pi E}{hc^2}\vec{A}\cdot\vec{\Omega}$. We present an experiment using a ground state Zeeman qubit and a modified version of the recently developed spindependent kicks technique [1] to create an interferometer with a single $\rm^{138}Ba^+$ ion in a linear Paul trap ($r_0=1$ cm) [2]. With a trap this large it is difficult to operate in the LambDicke regime, but the initial ion velocity may only reduce contrast and will not produce an additional phase shift. We will reach sensitivities comparable to other matterwave interferometers $(\sim 1\ \rm\mu rad \ s^{1}Hz^{1/2})$ by taking advantage of the extra energy afforded by using massive particles and the long coherence time of the ion (at least 1 s), allowing it to orbit in the trap many times before closing the interferometer. \begin{thebibliography}{9}\bibitem{S}J. Mizrahi et al., Phys. Rev. Lett.\bf 110\rm, 203001 (2013)\bibitem{u}W. C. Campbell and P. Hamilton, J. Phys. B.\bf 50\rm, 064002 (2017)\end{thebibliography} [Preview Abstract] 

M01.00095: Dynamics of Fermi gases near $s$wave and $p$wave Feshbach resonances Ben A. Olsen, Scott Smale, Kenneth G. Jackson, Peiru He, Jamir Marino, Ana Maria Rey, Joseph H. Thywissen Using a Fermi gas of potassium atoms, we explore different regimes of dynamics by varying the strength of $s$wave and $p$wave interactions. Near the zero crossing of the $s$wave Feshbach resonance, we observe magnetization dynamics using a Ramsey sequence of radiofrequency pulses. For sufficiently weak interactions, the motional degrees of freedom are fixed, and the cloud realizes a quantum simulation of the collective Heisenberg lattice spin model in harmonic oscillator mode space. This system exhibits a dynamical phase transition between a ferromagnetic phase with longlived magnetization, and a fastdecaying paramagnetic state. We also investigate the behavior of a spinpolarized cloud tuned near a $p$wave Feshbach resonance. We report on the effects of strong confinement on energetics of the cloud, observed through loss features and radiofrequency spectroscopy. These studies have implications for the stability of Fermi gases with strong $p$wave interactions. [Preview Abstract] 

M01.00096: Strongly interacting homogeneous Fermi gases in two and three dimensions Cedric Wilson, Biswaroop Mukherjee, Zhenjie Yan, Parth Patel, Airlia Shaffer, Lev Kendrick, Julian Struck, Richard Fletcher, Martin Zwierlein We create and study a homogeneous Fermi gas with strong interactions in uniform trapping potentials. Here we present three current research themes, and outlook for future experiments. We study the temperature dependence of spin impurities and observe a polaron to bare particle crossover, observe quantum limited sound attenuation by local density modulation, and present measurements of the temperature dependence of the contact. Furthermore, we detail progress on upgrading our apparatus for achieving a uniform 2d Fermi gas with strong interactions. [Preview Abstract] 

M01.00097: Detecting spin nematicity via optical birefringence effects in spinor BoseEinstein condensates Mickie Eikenberry, Tao Tang, Zihe Chen, Lichao Zhao, Yingmei Liu We present an experimental study on detecting the spin nematicity of an antiferromagnetic spinor BoseEinstein condensate via its optical birefringence effects. The diagonal elements of a spin nematic tensor are only related to fractional populations of all spin components, while its offdiagonal elements reflect interesting optical birefringence effects. We determine values of these offdiagonal elements by applying a wellselected light beam onto the spinor gases and detecting changes in the beam’s polarization after the beam passes the gases. One important application of this detection method is to identify various important spin states. In this presentation, we demonstrate how to utilize this detection technique to distinguish two ground states of the antiferromagnetic spinor gases, i.e., a polar (spinsinglet) state with a nonzero (zero) spin nematicity. [Preview Abstract] 

M01.00098: Improved apparatus for the study of sodium spinor BoseEinstein condensates Jamie Luskin, Donald Fahey, Alexander Impertro, Zachary Glassman, Paul Lett We present the design of a sodium BEC apparatus optimized to perform belowSQL spin interferometric measurements and study coherent spinor dynamics in condensates at finite temperature. One of the features of this apparatus is an improved imaging capability due to reentrant windows in a planar chamber geometry designed for a custom high NA objective that will allow for in situ and single atom detection. Design details and preliminary results will be discussed. [Preview Abstract] 

M01.00099: Offsite driven spin exchange interaction in a dipolar band insulator. Lauriane Chomaz, Simon Baier, Daniel Petter, Alexander Patschneider, Jan Hendrick Becher, Gabriele Natale, Manfred Mark, Francesca Ferlaino Ultracold gases of highly magnetic atoms such as erbium offer an ideal platform for investigating novel aspects of manybody quantum phenomena in the presence of dipoledipole interactions. We have realized and studied tunable~spin mixtures of~fermionic erbium 167. Our achievements rely on a lattice protection technics, which enable, for the preparation time, to turn off the scattering processes between the atoms. In this poster I will present our study of spin dynamics of the fermi gas in a deep lattice prepared in distinct spin states. Our experimental tunability enables us to prepare unit filling samples of fermions in the lattice lowest band and to change the atoms internal state to a pure spin state of higher quantum number. A magnetizationconserving flipflop dynamics shows a resonant behavior with the relative detuning of the neighboring spin states, which we can experimentally tune thanks to quadratic Zeeman and light shifts. We investigate the characteristic dependences of the dynamics on resonance, with the spin state quantum number and with the quantization axis. [Preview Abstract] 

M01.00100: Thermalization near integrability in a dipolar quantum Newton's cradle Wil Kao, Yijun Tang, KuanYu Li, Sangwon Seo, Krishnanand Mallayya, Marcos Rigol, Sarang Gopalakrishnan, Benjamin Lev Isolated quantum manybody systems with integrable dynamics do not thermalize starting from generic initial states. As one perturbs such systems away from integrability, thermalization sets in, but the nature of the crossover from integrable to thermalizing behavior remains unclear. We investigate this problem by studying the dynamics of the momentum distribution in a dipolar quantum Newton's cradle consisting of highly magnetic dysprosium atoms  the first onedimensional Bose gas with strong, tuneable magnetic dipoledipole interactions. We provide the first experimental evidence that thermalization close to integrability exhibits a fast dephasing followed by nearexponential thermalization, and the measured thermalization rate is consistent with a parameterfree theoretical estimate. By providing tunability between regimes of integrable and nonintegrable dynamics, our work sheds light on the temporal structure by which isolated quantum manybody systems approach thermalization. [Preview Abstract] 

M01.00101: TunableRange, PhotonMediated Atomic Interactions in Multimode Cavity QED Yudan Guo, Varun Vaidya, Ronen Kroeze, Kyle Ballantine, Alicia Kollar, Jonathan Keeling, Benjamin Lev Optical cavity QED provides a platform with which to explore quantum manybody physics in drivendissipative systems. Singlemode cavities provide strong, infiniterange photonmediated interactions among intracavity atoms. However, these global alltoall couplings are limiting from the perspective of exploring quantum manybody physics beyond the meanfield approximation. The present work demonstrates that local couplings can be created using multimode cavity QED. This is established through measurements of the threshold of a superradiant, selforganization phase transition versus atomic position. Specifically, we experimentally show that the interference of neardegenerate cavity modes leads to both a strong and tunablerange interaction between BoseEinstein condensates (BECs) trapped within the cavity. We exploit the symmetry of a confocal cavity to measure the interaction between real BECs and their virtual images without unwanted contributions arising from the merger of real BECs. Atomatom coupling may be tuned from short range to long range. This capability paves the way toward future explorations of exotic, strongly correlated systems such as quantum liquid crystals and drivendissipative spin glasses. [Preview Abstract] 

M01.00102: Interaction Quench dynamics of fewboson ensembles in optical lattices with spatially modulated interactions Simeon Mistakidis, Thies Plassman, Peter Schmelcher The nonequilibrium quantum dynamics of few boson ensembles which experience a spatially modulated interaction strength and are confined in finite optical lattices is investigated. Performing quenches either on the wavevector or the phase of the interaction pattern an enhanced imbalance of the interatomic repulsion between distinct spatial regions is induced. Following both quench protocols triggers various tunneling channels and a rich excitation dynamics consisting of a breathing and a cradle mode. All modes are shown to be amplified for increasing inhomogeneity amplitude. Especially the phase quench induces a directional transport enabling us to discern energetically, otherwise, degenerate tunneling pathways. Moreover, a periodic (consecutive) population transfer between (to higher) lattice momenta for quenches of increasing wavevector (phase) is observed. Finally, regions of partial coherence are revealed between the predominantly occupied wells during the evolution. [Preview Abstract] 

M01.00103: Progress on direct photoassociation of halo molecules in ultracold $^{86}$Sr James Aman, Joshua Hill, R. Ding, F. B. Dunning, T. C. Killian We report progress on the creation of $^1S_0$+$^1S_0$ halo molecules in strontium 86 through direct photoassociation in an optical dipole trap. By driving a two photon Raman transition nearresonance with a molecular level of the $^1S_0$+$^3P_1$ interatomic potential, we explore a unique regime of photoassociation where the driving fields are separeted by small energy differences. A simple isolated resonance model confirms the binding energy, $E_b \approx 84$ kHz at low excitationlaser intensity. Additionally, we have investigated the effects of density shifts and trap intensity on the observed halo binding energy. Large observed FrankCondon factors suggest that STIRAP should be very effective for improving molecular conversion efficiency. Further experiments in a 3D lattice will explore molecular lifetimes and collision rates. [Preview Abstract] 

M01.00104: Cold chemistry with trapped ions C. D. Ahl, J.M. Hanson, M. Okane, B.R Slimmer, M. Yeates, S.J. Bromley, J.P. Marler Experimental study of chemical reactions at low temperatures gives insight into the rotationally and vibrationally resolved properties of molecules with an unprecedented precision. Specifically such experiments offer new clues to the dynamics of charge exchange and molecule formation and dissociation at low interaction temperatures. Trapped ions represent a unique system for such experiments down to the mK energy scale. Large trap depths allow for the charged products of such collisions to remain trapped and the products studied in detail. Taking advantage of the ability to easily cotrap laser coolable atomic ions with various atomic or molecular ions of interest opens up a large variety of possible interactions ranging from fundamental physics to astrochemical or biological systems. [Preview Abstract] 

M01.00105: A new density regime for cold hydroxyl radicals David Reens, Hao Wu, Tim Langen, Anna McAuliffe, Noppodol Punsuebsay, Jun Ye With the goal of studying hydroxyl radicals in the ultracold regime typically attained with alkali atoms, we are pursuing evaporative cooling of a 50 mK trapped sample decelerated from a molecular beam. To this end, we have recently developed a novel trap that is plugged against spinflip losses. We are also unveiling a successfully remodeled system with nearly a 100fold increase in molecule density. We will be reporting on exciting evidence of strong molecular collisional effects obtained with this system. [Preview Abstract] 

M01.00106: A protocol to synthesize ultracold polyatomic molecules using an optical lattice Jia Yao, Kaden R.A. Hazzard We theoretically explored a technique of synthesizing fouratom molecules (tetramers) from ultracold diatomic molecules using an optical lattice or optical tweezers. Polyatomic molecules cooled down to ultracold temperature can drive interesting dynamics and phases of matter due to their rich rotational and vibrational bound states. However, the complexity of their internal structures remains as an obstacle for cooling tetramers with traditional laser cooling methods. Recently, longlived, groundstate, diatomic, nonreactive molecules have been created in an optical lattice. We devise a technique to synthesize an excited tetramer molecule in a welldefined bound state by driving two diatomic, groundstate molecules, such as RbCs or NaK, from adjacent sites onto the same lattice site via a short period of tunneling. We numerically model the tunneling process, where two precooled molecules associate into a mixture of tetramer bound states. We demonstrate high probabilities of producing tetramers in a single excited bound state within an optimal range of lattice depths. Our approach of synthesizing excited tetramers opens a possible route towards groundstate tetramers. [Preview Abstract] 

M01.00107: Improving the state selectivity of field ionization with quantum control Vincent C. Gregoric, Ankitha Kannad, Zhimin Cheryl Liu, Thomas J. Carroll, Michael W. Noel The state distribution of a collection of Rydberg atoms can be determined by ionizing the atoms with a slowly increasing electric field, a process known as selective field ionization. Generally, atoms in higher energy states are ionized at lower fields, so ionized electrons which are detected earlier in time can be correlated with higher energy Rydberg states. The resolution of this technique is limited by the Stark effect; as the electric field is increased, the electron encounters many avoided Stark level crossings which split the amplitude among many states, thus broadening the timeresolved ionization signal. Previously, we have demonstrated ``directed field ionization,'' a modification of selective field ionization in which we use a genetic algorithm to exert quantum control over the timeresolved ionization signal shape of a single Rydberg state\footnote{V. Gregoric, \textit{et al.}, Phys. Rev. A \textbf{96}, 023403 (2017)}. Here, we present an extension of this work to separate the signals from two states which are originally overlapped in our selective field ionization signal. [Preview Abstract] 

M01.00108: Rydberg atoms in the presence of a continuum of scatterers Jovica Stanojevic, Robin Cote We study Rydberg atoms in dense environments assuming that a very large number (in practice tens of thousands) of groundstate atoms (scatterers) are localized within the volume of a single Rydberg atom. A Green's function based approach is used to derive a nonperturbative inhomogeneous differential equation for the Rydberg electron wave function in the limit of a continuum scatterer density. In this description, the scatterers influence the Rydberg wave function through an inhomogeneous term in the Schr\"odinger equation. In turn, the Rydberg wave function affects the local scattering amplitudes of the many scatterers and the relationship between these amplitudes and the Rydberg wave function is found by solving the local scattering problem. Solutions of the inhomogeneous Schr\"odinger equation yield the energy shifts of the Rydberg levels. We also derive an effective potential that a single scatterer experiences inside a Rydberg atom. [Preview Abstract] 

M01.00109: Laser Cooling of Ions in a Neutral Plasma Grant Gorman, Thomas Langin, Thomas Killian Ultracold neutral plasmas (UNPs), created by photoionization of an ultracold atomic gas, are an excellent tool for studying strongly coupled plasmas. The ion Coulomb coupling parameter, $\Gamma_{i}$, which is the ratio of the nearest neighbor Coulomb energy to the average thermal energy, has been limited to $\Gamma_{i}\sim$3 due to disorderinduced heating. We overcome this limitation by laser cooling the ions after photoionization, observing a factor of four reduction in temperature after 135 $\mu$s of cooling, achieving coupling as high as $\Gamma_{i}$=11. This regime is beyond the range of validity of current theoretical models, thus, the application of established techniques to measure collision rates, transport properties, and dispersion relations will allow for experimental tests of new models that seek to extend into the strong coupling regime. We also demonstrate that the optical forces can slow this expansion, opening new possibilities for confinement and manipulation of UNPs. This poster will discuss the challenges associated with laser cooling of ions in an expanding neutral plasma along with the exciting new possibilities stronger coupling brings. [Preview Abstract] 

M01.00110: Rydberg polariton threebody interactions Dalia Ornelas, Alexander Craddock, Mary Lyon, Nathan Fredman, Michael Gullans, Steve Rolston, Trey Porto The combination of atomic Rydberg interactions with electromagnetically induced transparency is a promising candidate for a wide range of applications for quantum optics, quantum information protocols and the study of manybody physics. These systems are a novel platform to study fewbody physics where the dimensionality, mass, strength and sign of the interactions are all widely controllable and tunable, as has been demonstrated in recent experiments observing the formation of two and threephoton bound states. In this work, we present preliminary experimental results of an observed effect in a lowdensity RydbergEIT medium, where threebody loss is dominant over twobody loss, opening the door to do a more extensive study of fewbody physics with Rydberg polaritons. [Preview Abstract] 

M01.00111: Production of veryhighn Rydberg atoms in an optical dipole trap S.K. Kanungo, R. Ding, J.D. Whalen, F.B. Dunning, T.C. Killian Veryhighn (n $\ge $ 300), Rydberg states can be manipulated with remarkable precision using carefullytailored series of electric field pulses which enables control of their interactions. Highn states, however, are strongly perturbed by stray fields which must therefore be reduced to very small levels. Whereas selective excitation to states with n \textgreater 500 has been achieved using large, closed electrode geometries, the optical access required to generate cold atom samples precludes the use of similar geometries. We will describe progress towards nulling the stray electric fields in an apparatus capable of producing quantum degenerate Strontium gases by utilizing Stark spectroscopy and application of small offset potentials to two sets of nearby electrodes. Methods that might be used to automate this process are also being explored. [Preview Abstract] 

M01.00112: Compressive imaging of ultracold atomic clouds Joseph D. Murphree, Maitreyi Jayaseelan, Zekai Chen, Justin T. Schultz, Nicholas P. Bigelow Imaging is one of the primary ways spatial density and phase information is obtained from ultracold atomic clouds. Absorption imaging, one of the simplest and earliest methods, has been complemented by techniques that allow for the phase and polarization of a sample to be probed, or for the sample to be imaged nondestructively. Meanwhile, compressive sensing (CS) has increased the performance of a variety of imaging systems by extracting image information more efficiently than traditional imaging. Furthermore, the optics used in many of these CS implementations, such as digital micromirror devices, are becoming increasingly familiar in atomic physics labs, where the technique has already been used to improve spectroscopy. We investigate the use of CS to improve the efficiency of imaging of ultracold atomic clouds. [Preview Abstract] 

M01.00113: Engineering arbitrary analog spacetime metrics in an atomic quantum gas ChengAn Chen, May Kim, Yiyang Feng, ChenLung Hung We report our progress toward the construction of a quantum gas apparatus capable of engineering atomic interactions and simulating quantum fields in analog spacetime metrics with high spatial and temporal resolutions. Our experimental platform is a microscopeaddressed, homogeneous twodimensional cesium quantum gas loaded in an optical lattice. Through projecting light potential using a digital mirror device, we will perform dynamical optical Feshbach tuning of atomic interactions in an engineered spatial and temporal pattern. We describe possible explorations of a broad range of near/nonequilibrium quantum phenomena including acoustic black holes and Hawking radiations as well as quantum critical transport. [Preview Abstract] 

M01.00114: NASA's Cold Atom Laboratory (CAL): system integration and ground tests David Aveline, Ethan Elliott, Jason Williams, Rob Thompson We report on the current status of NASA's Cold Atom Laboratory (CAL), an ultracold quantum gas instrument developed by NASA's Jet Propulsion Laboratory (JPL). Once installed inside the International Space Station (ISS), it will provide the first persistent quantum gas platform in the microgravity environment of space. CAL is a multiuser facility equipped with rubidium and bosonic potassium atoms, allowing production of quantum gas mixtures and a wide range of fundamental physics studies. In microgravity, the confining potentials for cold atoms can be arbitrarily weakened to gain access to ultralow densities and pikoKelvin temperatures. This new parameter regime enables ultracold atom research by an international group of researchers with broad applications in fundamental physics and inertial sensing. We describe the integration and ground testing as the CAL instrument prepares for launch to the ISS. [Preview Abstract] 

M01.00115: A cold atomnanophotonic apparatus for exploring photonmediated longrange atomatom interaction TzuHan Chang, Brian Fields, May Kim, ChengAn Chen, ChenLung Hung Studying manybody systems subject to longrange interactions experimentally has remained a difficult problem. Experiments with trapped atoms near nanoscale photonic waveguides and cavities have demonstrated the possibility in using strong coupling between single atoms and single photons to mediate longrange interactions between atomic pseudo spins. It would also be possible to engineer various longrange quantum spin models that are otherwise difficult to achieve in other systems. We expect to observe rich physics arising from these new hybrid platforms. In this poster, we report on our progress towards building an apparatus for the exploration of photonmediated longrange atomatom interaction. Specifically, we describe the synthesis of an optical chip with microring resonators, and the localization of an array of atoms loaded in optical tweezer traps to induce strong atomlight coupling in the resonator. [Preview Abstract] 

M01.00116: A twospecies fivebeam magnetooptical trap for highly magnetic Er and Dy atoms Gianmaria Durastante, Philipp Ilzhoefer, Alexander Patscheider, Claudia Politi, Maximilian Sohmen, Arno Trautman, Manfred Mark, Frencesca Ferlaino We report on the first realization of a twospecies magnetooptical trap (MOT) for erbium and dysprosium. The MOT operates on an intercombination line for the respective species. Owing to the narrowline character of such a cooling transition and the action of gravity, we demonstrate a novel trap geometry employing only five beams in orthogonal configuration. We observe that the mixture is cooled and trapped very efficiently, with up to $5 \times 10^{8}$ Er atoms and $10^{9}$ Dy atoms at temperatures of about 10 $\mu K$. Our results offer an ideal starting condition for the creation of a dipolar quantum mixture of highly magnetic atoms. [Preview Abstract] 

M01.00117: A chipscale, opticalcavitybased dynamic force sensor Benjamin Reschovsky, Nicholas Vlajic, Akobuije Chijioke Measuring dynamic forces is extremely important for a variety of industrial process. However, the typical methods used to measure dynamic forces are not SItraceable and suffer from poorly understood uncertainties. Since dynamic calibration is often difficult, a common practice is to assume a static calibration is valid over the entire tested bandwidth instead of performing a calibration of the true dynamic response of a force transducer, introducing an unknown amount of error. This approach is only accurate at frequencies much less than the lowest mechanical resonance of the transducer where the dynamic response is nearly flat. We describe a new type of force transducer based on highquality, monolithic optical cavities. As a force is applied to the device, the dimensions of the cavity are slightly deformed leading to a shift in the cavity resonance frequency. This frequency shift can be detected with a differential measurement scheme, allowing for the cancellation of drifts due to environmental fluctuations such as temperature. The optical cavity approach is appealing because it should lead to compact, stiff devices with large mechanical resonance frequencies, high sensitivity, and high linearity. [Preview Abstract] 

M01.00118: Nanophotonic cavity QED with individually trapped atoms Paloma Ocola, Tamara Dordevic, Polnop Samutpraphoot, Hannes Bernien, Crystal Senko, Sylvain Schwartz, Alexander Zibrov, Vladan Vuletic, Mikhail Lukin The realization of strong atomphoton interactions is a central theme in quantum optics and an essential prerequisite for future quantum applications. We achieve such interactions using a hybrid system of neutral atoms and optical photons coupled via a nanoscale photonic crystal waveguide cavity [1]. Here, we demonstrate strong coupling between the cavity and two individual atoms trapped in optical tweezers. Our experimental effort aims at creating entangled states between two atoms using interactions mediated by cavity photonsa cornerstone for building scalable quantum gates [2]. [1] J. D. Thompson, T. G. Tiecke, N. P. de Leon, J. Feist, A. V. Akimov, M. Gullans, A. S. Zibrov, V. Vuletić, and M. D. Lukin, Science 340, 1202 (2013) [2] T. G. Tiecke, J. D. Thompson, N. P. de Leon, L. R. Liu, V. Vuletic and M. D. Lukin, Nature 508, 241 (2014) [Preview Abstract] 

M01.00119: Strongly Interacting mmWave and Optical Photons with Rydberg Atoms Mark Stone, Aziza Suleymanzade, Jasmine Kalia, Lin Su, Joshua Wakefield, David Schuster, Jonathan Simon We describe progress towards a hybrid experimental system for engineering strong interactions between single optical and mmwave photons using Rydberg atoms as an interface. Entanglement between photons with gigahertz and optical frequencies creates a new platform to access exotic photonic quantum states as well as powerful new techniques in quantum computing and simulation. We will present recent experimental developments including trapping and cooling atoms in a cryogenic MOT, measuring highQ superconducting cavities at 100 GHz using a novel photonic crystal design, and coupling atoms to an optical cavity inside a cryostat at 3 Kelvin. Finally, we present a scheme to lock a single optical cavity at two independent resonant frequencies using a silicon nitride membrane, which allows cavity enhancement at both frequencies in an EIT process. [Preview Abstract] 

M01.00120: Levitated NanoMagnets as Quantum Transducers Jan Gieseler, Arthur Safira, Aaron Kabcenell, Emma Rosenfeld, Martin Schütz, Mikhail Lukin Coherent coupling between a single spin and a massive mechanical mode is still an outstanding challenge. Such a system is highly desirable, as it allows preparation of macroscopic quantum states of motion and could be used to mediate longrange spinspin interactions. One promising approach to engineer a strong spinmechanical coupling is via magnetic field gradients. Maximizing the coherent coupling requires a compliant, high quality mechanical resonator, strong magnetic field gradients, and spin qubits with very long spin coherence times. In addition, they have to be combined while preserving the excellent properties of the individual components. To address this formidable challenge, we propose a new platform based on levitated magnets. Here, we report on our experimental progress towards integrating a levitated micromagnet with nitrogenvacancy (NV) centers in diamond as a new platform for quantum applications. The absence of any support structure yields low mechanical damping and a large magnetic moment to mass ratio, thereby enabling strong coupling. This hybrid setup gives controllable access to the rich, tunable mode spectrum associated with the micromagnet, consisting of hybridized translational, rotational and internal magnonic modes ranging from kHz to GHz. [Preview Abstract] 

M01.00121: Quantum dynamics of coupled spin defects in diamond Chong Zu, Francisco Machado, Bryce Kobrin, Thomas Mittiga, Satcher Hsieh, Prabudhya Bhattacharyya, Soonwon Choi, Norman Yao Understanding and controlling the dynamics of disordered, strongly interacting spin systems remain an outstanding challenges. Here, we demonstrate that in Type Ib diamond, the mixed electronic spin system associated with P1 centers (nitrogen defects) and nitrogenvacancy (NV) centers provides a natural playground to explore nonequilibrium quantum dynamics. The typical NVP1 spacing can be as small as a few nanometers, resulting in strong magnetic dipoledipole interactions between spins. By tuning an external magnetic field, one can vary the effective coupling strength between individual NV centers and nearby P1 centers, enabling the direct extraction of P1 density. Moreover, leveraging the NV center as an entropy sink, we initialize the spin state of nearby P1 centers and observe the resulting outofequilibrium quantum dynamics and spin diffusion. [Preview Abstract] 

M01.00122: Spectrally entangled twophoton state of cascade emissions from Dopplerbroadened atomic ensemble T. H. Chang, H. H. Jen We theoretically investigate the spectral entanglement of twophoton state from Dopplerbroadened atomic ensemble. The twophoton state is spontaneously generated from weak twocolor excitations in a diamondtype atomic level under the fourwave mixing condition. The upper and lower transitions can be in telecom and infrared wavelengths, which respectively are preferential for quantum communication and quantum memory. In a Dopplerbroadened atomic ensemble, the spectral entanglement is determined by excitation pulse duration, superradiant linewidth of the lower transition, and the temperature of atoms. We derive the spectral function of this twophoton source, and use Schmidt decomposition to study the competing effect of temperature and superradiant linewidth on the continuous frequency entanglement. This enables quantum control and manipulation of spectral entanglement of the twophoton source, which is potentially useful for quantum information applications in vapor cells. [Preview Abstract] 

M01.00123: A Rydberg impurity in a Fermi sea. John Sous, Richard Schmidt, Eugene Demler, Hossein Sadeghpour Mesoscopic Rydberg impurities in BoseEinstein condensates have emerged as a new platform to study impurity dynamics in a manybody bosonic environment revealing unique features such as polaronic dressing by molecule formation and a Gaussian spectrum, both of which were measured in recent experiments. We study the problem of a Rydberg impurity in a Fermi sea and analyze the absorption spectrum using an exact functional determinant approach. The longrange Rydberg potential leads to qualitatively different physics from the case of contact interactions in Fermi polaron problems. We discuss the implications of our results for impurity excitations in fermionic ultracold atomic systems. [Preview Abstract] 

M01.00124: Optical trapping of CaF Loic Anderegg, Benjamin Augenbraun, Lawrence Cheuk, Yicheng Bao, Sean Burchesky, Wolfgang Ketterle, John Doyle We demonstrate a highdensity RF magnetooptical trap of CaF molecules. Grey molasses cools the CaF molecules well below the Doppler limit to 30 uK allowing us to load the molecules into an optical dipole trap. Optical trapping lays the groundwork for many research directions, including ultracold collisions and chemistry, quantum simulations, and new precision measurements. A particularly promising avenue is constructing optical tweezer arrays of molecules, where one can realize full quantum control in a scalable platform. [Preview Abstract] 

M01.00125: Long range Rydberg molecules interacting with a dense random gas Jan Michael Rost, Perttu Luukko Trilobites are exotic giant dimers with enormous dipole moments. They consist of a Rydberg atom and a distant groundstate atom bound together by shortrange electronneutral attraction. Highly polar, polyatomic trilobite states unexpectedly persist and thrive in a dense ultracold gas of randomly positioned atoms [1]. This is caused by perturbationinduced quantum scarring and the localization of electron density on randomly occurring atom clusters. At certain densities these states also mix with an sstate, overcoming selection rules that hinder the photoassociation of ordinary trilobites. \\[5mm] [1] P.J.J. Luukko and J.M. Rost, PRL 119, 203001 (2017). [Preview Abstract] 

M01.00126: Ytterbium Rydberg atom arrays Samuel Saskin, Jack Wilson, Jeff Thompson Neutral atoms in optical tweezers are an attractive platform for both quantum computation and simulating quantum manybody physics, because of the combination of single site control and long range interactions via Rydberg excitations. While such systems have previously been explored in alkali atoms, the electronic structure of alkaline earth atoms, such as Yb, presents several advantages. These include longlived nuclear spin states ($I=1/2$ in $^{171}$Yb), and improved cooling and state manipulation using the narrow intercombination line. I will discuss the features of individual Yb atoms in an optical tweezer array, as well as our progress towards the design and construction of such a system. Our ongoing efforts are aimed at spectroscopy of Yb Rydberg levels, trapping Yb atoms in optical tweezers, and characterization of singleatom manipulation and measurement techniques. [Preview Abstract] 
(Author Not Attending)

M01.00127: Universal Relations of Ultracold Fermi Gases with Arbitrary SpinOrbit Coupling Jianwen Jie, Ran Qi, Peng Zhang We derive the universal relations for an ultracold twocomponent Fermi gas with spinorbit coupling (SOC)Weconsider the system with answave shortrage interspecies interaction, and ignore the SOCinducedmodification for the value of the scattering length. Using the firstquantized approach developedby S. Tan (Phys. Rev. Lett.107, 145302 (2011)), we obtain the shortrange and highmomentum expansions for the onebody realspace correlation function and momentum distribution function, respectively. For our system these functions are 2 dimension matrix in the pseudospin basis. We find thatthe leadingorder (1/$_{\mathrm{k4}})$ behavior of the diagonal elements of the momentum distribution function are not modified by the SOC. However, the SOC can significantly modifythe behavior of the nondiagonal elementsof the momentum distribution functionin the largeklimit. In the absence of the SOC, the leading order of these elements isO(1/k6)When SOC appears, it can induce a term on the order of 1/$_{\mathrm{k5}}$. We further derive theadiabatic relation and the energy functional. Our results show the SOC can induce a new term inthe energy functional, which simply describe the contribution from the SOC to the total energy.The form of the adiabatic relation for our system is not modified by the SOC. [Preview Abstract] 

M01.00128: A general numerical method for twoparticle scattering in the presence of spinorbit coupling SuJu Wang, Qingze Guan, D. Blume The scattering problem in quantum mechanics is usually reduced to solving a set of coupled multichannel equations in the radial coordinate by expanding the full solution in terms of a complete set of basis functions. When an adiabatic basis set is chosen, a firstderivative term with respect to the radial coordinate appears because of the parametric dependence of the basis functions on the radial coordinate. The symmetrized generalized logderivative method has been shown to solve this type of problem efficiently [1]. We show that the method can also be applied to the scattering problem in the presence of synthetic spinorbit coupling, where the firstderivative term originates from the intrinsic coupling between the spin and spatial degrees of freedom, independent of the choice of the basis set. We demonstrate the efficiency of this method for two particles in a wave guide in the presence of spinorbit coupling. The scattering observables are analyzed in detail and the physical origin behind the rich resonance structure is discussed. [1] F. Mrugala, J. Chem. Phys. 79, 5960 (1983). [Preview Abstract] 

M01.00129: Interactionenabled chiral trajectories in a ladder governed by the HarperHofstadter Model Matthew Rispoli, M. Eric Tai, Alex Lukin, Robert Schittko, Tim Menke, Daniel Borgnia, Philipp Preiss, Fabian Grusdt, Adam Kaufman, Markus Greiner The combination of interacting charged particles and magnetic fields can to lead to exotic phases of matter that exhibit high degrees of spatial entanglement and topological order. Ultracold atoms and optically engineered artificial gauge fields have been used to study a number of single particle effects, such as edge states, topological band structures, and the quantum hall effect. However, these experiments have not yet incorporated interparticle interactions. I will describe recent experimental results in which we combine microscopy, interacting atoms, and the presence of a synthetic magnetic field in a 2xN realspace ladder. In particular, we observe the chiral dynamics of both singleparticle and twoparticle systems with strong, finite interactions. We show the interactions for the twoparticle system enable these chiral dynamics where they would otherwise be absent. Additionally, the observed correlations distinguish the presence of states with bound and freeparticle character and their contributions to the chirality. Our observation of a novel form of interactionenabled chirality illustrates the rich physics that can emerge with these ingredients even in the few particle limit. Realizing this combination of elements is essential to advance into the regime of fractional quantum hall physics, as well as to drive explorations for new phenomena with the microscopic tools of AMO systems. [Preview Abstract] 

M01.00130: Towards quantum manybody physics with Sr in optical lattices Sebastian Blatt, André Heinz, Annie Jihyun Park, Fabian Finger, Stepan Snigirev, Jean Dalibard, Immanuel Bloch The widespread use of ultracold fermionic strontium atoms in optical lattices for precision measurements has led to the availability of many advanced tools and techniques for these atoms. With the recent realization of degenerate gases of all Sr isotopes and the development of fermionic quantum gas microscopes for alkali metal atoms, a new frontier has opened for quantum simulations and quantum information processing with fermionic $^{87}$Sr. Many applications in quantum state engineering and quantum simulation require internalstatedependent control of the atomic motion. In the Sr atom, there exist socalled tuneout wavelengths, where only one of the clock states is trapped and the other state can move freely. Because of the (in principle) exact cancellation of the other state's polarizability at the tuneout wavelengths, it should be possible to realize spindependent lattices with high fidelity. Here, we propose a system to realize such internalstatedependent control of the atomic motion and report on the construction of a new experiment towards quantum simulations with Sr in optical lattices. [Preview Abstract] 

M01.00131: Compressibility of a 3D Disordered Bose Lattice Gas Philip Russ, Laura Wadleigh, Brian DeMarco Studying the behavior of quantum systems at the intersection of strong interactions and disorder has played a central role in advancing our understanding of fundamental concepts such as manybody localization. The disordered BoseHubbard model is a minimal model incorporating these ingredients that supports a disorderdriven phase transition between the Mott insulator and Bose glass phase at low temperature and for strong interactions. We study the evolution of a unit filling, finite temperature Mott insulator with increasing disorder by measuring compressibility. To increase our measurement resolution, we implement machine learning tools to analyze timeofflight images of the atomic density profile. [Preview Abstract] 

M01.00132: A Quantum Gas Microscope for Microwave Photons Brendan Saxberg Synthetic photonic systems are a promising platform for new physics in the regime of strongly interacting and highly correlated quantum materials. We present our implementation of a strongly interacting Bose Hubbard lattice in the Circuit QED framework by capacitively coupling a 1D lattice of transmon qubits, where the anharmonicity of the transmons provides the effective onsite interaction. Individual readout resonators allow site, time, and occupancy resolved microscopy of the photonic lattice. To stabilize the Mott Insulating phase of light in this lattice we couple our lattice to an autonomous stabilizer  a single lattice site that is continuously driven into the n$=$1 excited state. This scheme stabilizes the Mott phase, and indeed any manybody target state, so long as the phases are incompressible with respect to photon number. We present Mott phase stabilization data characterizing its performance as well as other experiments on our 1D chain such as quantum random walks. This passive state preparation through our stabilizer provides an avenue for stabilizing novel manybody states like topological lattices with photonphoton interactions. [Preview Abstract] 

M01.00133: Phase coherence properties of ultracold Bose gas in optical trimerized Kagome lattice TszHim Leung, Thomas Barter, Masayuki Okano, Maxwell Block, Norman Yao, Dan StamperKurn The trimerized (breathing) Kagome lattice, which can be seen as a triangular lattice of trimers, has attracted significant theoretical interests in recent years. This lattice is an extension of the normal Kagome lattice that it has different intra (J) and intertrimer (J') tunneling, leading to a richer spatial structure and possibility to host novel quantum states. We report the experimental realization of the BoseHubbard model in an optical trimerized Kagome lattice with $^{\mathrm{87}}$Rb atoms and optical superlattice techniques, with the capability of independently tuning the inter and intratrimer tunneling, as well as the relative offsets in a trimer. By studying timeof flight images, we measure the coherence of the system as it crosses the superfluid to Mott insulator transition and show that shortrange coherence within trimers could persist in certain parameter regimes. We make comparisons and show a clear difference between the trimerized Kagome lattice and the normal Kagome lattice. Furthermore, we modify the local wavefunction in a trimer using phase imprinting techniques and show asymmetric diffraction patterns, revealing asymmetric correlations in the system. [Preview Abstract] 

M01.00134: Phase Stabilized Arbitrary Lattices with Magnetic Levitation in TimeofFlight Z. S. Smith, M. E. W. Reed, A. Dewan, A. M. Stahl, S. L. Rolston We present three portions of our apparatus that enable ~60 ms timeofflight images to be taken of atoms released from arbitrary lattices. First, we present the generation of these optical lattices using a pair of AcoustoOptic Modulators [AOM]. Second, the phasestabilization of these lattices using an inhouse manufactured interferometer and piezoactuated mirror. Third, a magnetic levitation system for ${}^{87}$Rb using supercapacitors and a MOSFETbased switched circuit that enables 10's of ms timeofflight while staying in focus with a highresolution imaging system. [Preview Abstract] 

M01.00135: Hubbard Thermalization and Dynamics over Long Timescales Laura Wadleigh, Nicholas Kowalski, Philip Russ, Brian DeMarco Atomic lattice gases have been an important tool to study the Hubbard model. We explain a new technique we have developed to study Hubbard thermalization and dynamics over extraordinarily long timescales. A optical cylindrical barrier is used to create a hole in the density profile of a thermal gas of $^{87}$Rb atoms trapped in a cubic lattice. The barrier is suddenly removed, and insitu images are taken after waiting more than four orders of magnitude in tunneling time. We observe that the gas relaxes without a characteristic time scale, potentially indicating glassy dynamics arising from kinetic constraints. The effects of disorder, magnetic dipole interactions, excited band atoms, nearestneighbor interactions, and single particle localized states will be discussed. [Preview Abstract] 

M01.00136: Driven and dissipative quantum dynamics in ultralong lived dipoles in an optical cavity Diego Barberena, Robert LewisSwan, Ana Maria Rey Alkaline earth atoms (AEA) are becoming unique quantum platforms for the simulation of complex quantum manybody systems and for the realization of the most precise atomic clocks. Recent developments in cavity QED implementations using AEAs are now allowing us to take advantage of their longlived clock states and rich internal structure to explore a new regime of cavity QED where a single optical cavity mode can mediate strong exchange interactions and collective superradiant decay in manybody systems [1].~ Here we report new investigations in the regime where an external field is used to additionally coherently drive the clock transition. It is known that, even in the absence of exchange interactions, this system exhibits a dynamical phase transition and a steady state with useful entanglement properties.~ To assess possible experimental signatures of the dynamical phase transition and to analyze the modifications introduced by cavity mediated interactions, we study the long time behavior of different spin observables and the spectrum of the emitted light. We also investigate the modifications of the entanglement properties of the steady state generated by exchange interactions and how can they be used for enhanced metrology. [1] arXiv:1711.03673 [Preview Abstract] 

M01.00137: Exploring nonequilibrium quantum phenomena with ultracold lithium Kurt Fujiwara, Kevin Singh, Zachary Geiger, Mikhail Lipatov, Ethan Simmons, David Weld Ultracold lithium atoms in optical lattices provide a versatile platform for investigation of nonequilibrium quantum systems. We report on the first dynamical realization of a relativistic harmonic oscillator, on experimental characterization of a Floquet phase diagram in a stronglydriven optical lattice, on the first experimental measurement of positionspace centerofmass Bloch oscillations, and on the observation of largescale coherent transport in hybridized FloquetBloch bands. [Preview Abstract] 

M01.00138: Construction of a Quantum Matter Synthesizer Jonathan Trisnadi, Mickey McDonald, KaiXuan Yao, Cheng Chin We report progress on the construction of a new platform to manipulate ultracold atoms. The “Quantum Matter Synthesizer” will have the capability of deterministically preparing 2D arrays of atoms with single site addressability. Cesium atoms will first be transferred to a science cell via a moving 1D lattice, where they are loaded into a magicwavelength, fardetuned 2D optical lattice. Two NA=0.8 microscope objectives surround the science cell from above and below. Optical tweezers (formed by a digital micromirror device) and a 2D lattice potential are projected through the upper objective, and imaged with the lower objective. Siteresolved fluorescence images of the initial atomic distribution are taken using the upper objective. Additionally, we report on a new scheme to detect atoms with suboptical wavelength resolution. Starting from cesium atoms in a 3D optical lattice, we superimpose along one axis a standing wave of resonant light which can optically pump the atoms to a different hyperfine state suitable for imaging. The dependence of imaged atom number on relative phase between the trapping and pumping lattices is strongly related to the single atom density profile within a lattice site. [Preview Abstract] 

M01.00139: Cooperative light scattering from helicalphaseimprinted atomic rings HsiangHua Jen, M. S. Chang, Y. C. Chen We theoretically investigate the light scattering of the super and subradiant states which can be prepared by the excitation of a single photon which carries an orbital angular momentum (OAM). With this helical phase imprinted on the stacked ring of atomic arrays, the subradiant modes show directional side scattering in the farfield, allowing for light collimation and quantum storage of light with OAM. For the excitations with linear polarizations, we find a discrete $C_4$ rotational symmetry in scattering for the number of atoms $N=4n$ with integers $n$, while for circular polarizations with arbitrary $N$, the azimuthal and $C_N$ symmetries emerge for the super and subradiant modes respectively. When the radial and azimuthal polarizations are considered, a mode shift can happen in the scattering pattern. The forward scattering of the superradiant modes can be enhanced as we stack up the rings along the excitation direction, and for the subradiant modes, we find the narrowing effects on the scattering in the azimuthal and the polar angles when more concentric rings are added in the radial direction. By designing the atoms spatially, helicalphaseimprinted subradiant states can tailor the radiation properties, which is potentially useful in quantum information manipulations. [Preview Abstract] 

M01.00140: A telecomwavelength frequency downconversion based on a cold Rubidium atomic ensemble Wei Chang, Yunfei Pu, Nan Jiang, Chang Li, Sheng Zhang, Luming Duan Longdistance quantum communication is limited by exponential photon transmission losses in fiber. Typical transitions from groundlevel based on neutral atom or iron are in visible wavelengths or nearinfrared wavelengths, outside the telecomwavelength window. Telecomwavelength conversion is essential to solve this limitation. Here we report our progress in telecomwavelength frequency downconversion between 795nm and 1530nm in a cold optically thick gas of Rubidium87. Based on an EDMOT (Extended Dark MagnetoOptical Trap) with optical density above 30, an efficient fourwave mixing wavelengthconversion is realized. This conversion is using a 5S1/25P1/24D3/25P3/2 diamond configuration, achieving efficiencies up to 16{\%}. [Preview Abstract] 

M01.00141: Quantum simulations of the Dicke and transverse Ising models with hundreds of trapped ions K.A. Gilmore, J.E. Jordan, J.G. Bohnet, J.J. Bollinger, A. SafaviNaini, R.J. LewisSwan, A. Shankar, M. Holland, A.M. Rey, J. Cohn, J.K. Freericks, M. G\"{a}rttner Quantum simulators, where one wellcontrolled physical system mimics another complex system, may enable understanding of quantum manybody physics that cannot be fully studied using conventional techniques on classical computers. We describe quantum simulations of a network of interacting spins performed with 2dimensional arrays of hundreds of Be$^{+}$ ions crystallized in a Penning trap. We discuss how we engineer the Dicke model, where the spins are coupled to a single phonon mode, and the limits in which this becomes the transversefield Ising model, an effective spin model. We summarize experiments exploring adiabatic protocols for preparing low energy entangled states. We also present results of an EIT (Electromagnetic Induced Transparency) cooling experiment that shows average motional quantum numbers $\bar{n} < 1$ can be achieved in a few hundred microseconds. [Preview Abstract] 

M01.00142: Adiabatic Preparation of Strongly Correlated Manybody States Christopher Olund, Snir Gazit, John McGreevy, Norman Yao We present a novel algorithm for adiabatic preparation of strongly correlated manybody states. Our approach is based upon the socalled ssource framework, which constructs a quantum circuit that interpolates between the ground state of system size L and 2L. This procedure can then be iterated to reach the thermodynamic limit. In contrast with standard algorithms which rely on the variational principle, our approach is based on the adiabatic theorem and may prove particularly useful for Hamiltonians where variational methods tend to fail. We propose an explicit numerical scheme for optimizing the interpolating quantum circuit and benchmark it against DMRG for several spin chain models; even near a quantum phase transition, where the spectral gap is small, we observe good agreement between the methods. The algorithm also has a clear physical interpretation, providing a blueprint to physically prepare largescale manybody states from smaller systems via a series of local unitaries. [Preview Abstract] 

M01.00143: Characterization of an Atom Chip with Integrated Coplanar Waveguides Byron Lowry, Robert Wyllie, Michael Chapman, Creston Herold We describe a new neutral atom trapping apparatus at GTRI based on a multilayer atom chip that was designed and fabricated inhouse. The bottom conductive layer provides a set of flexible magnetic trap geometries, while the top layer integrates two microwave coplanar waveguides (CPWs) into a gold mirror. Here we present experimental characterization of the atom chip. Future work will focus on guided wave atom interferometry. Similar to the scheme proposed in [1], the near field pattern of the CPWs will be used to manipulate and dress the internal hyperfine states of the rubidium atoms. [1] Ammar M \emph{et al} 2015 Symmetric microwave potentials for interferometry with thermal atoms on a chip \textbf{Phys. Rev. A 91 053623} [Preview Abstract] 

M01.00144: Experimental realization of a guided matter wave interferometer with enclosed area Changhyun Ryu, Malcolm Boshier An atom interferometer has been developed mainly for inertial sensing application. For this application, it is necessary for an atom interferometer setup to be small enough to be deployable. A compact guided matter wave interferometer has been studied as a smaller alternative to a free space atom interferometer. One important requirement for general inertial sensing is to have enclosed area for rotation sensing. Here we will present the current status of our effort to realize a guided matter wave interferometer with enclosed area. The linear guide for a BEC consists of a single laser beam. This beam is sent through an AOM for the movement of the guide. The transport of atoms can be achieved by changing the frequency of an AOM with optimized waveforms. With this setup a BEC was moved up to 1.5mm with 20ms transport time with minimum excitation. The interferometer measurement was done with three standing wave light pulses and coherence was observed up to 40ms interrogation time. By applying interferometer pulses while the waveguide is moving, enclosed area can be created for a guided matter wave interferometer. We will report the progress on this effort. [Preview Abstract] 

M01.00145: BECCAL  Atom Optics with BECs on the ISS Dennis Becker, Kai Frye, Christian Schubert, Ernst Maria Rasel The NASADLR BoseEinstein condensate and Cold Atom Laboratory  called BECCAL  is a joint multiuser, multipurpose facility to exploit the unique microgravity conditions on the International Space Station (ISS) for complementary experiments with ultracold and condensed Rb and K atoms in regimes inaccessible on ground. In microgravity, no gravitational sag acts on an atomic ensemble, and it stays at rest with respect to its environment. This enables an extended time of flight in free fall at the order of seconds to tens of seconds, beyond the possibilities on earth. These two aspects are essential for the various experiments enabled by BECCAL. The system will be based on the drop tower and sounding rocket experiments QUANTUS and MAIUS including an atom chip for efficient evaporation and excellent control of the quantum degenerate atomic clouds. The setup will provide a variety of trapping potentials including static and RFdressed magnetic as well as red and bluedetuned optical potentials. It will serve as a platform to realize experiments in atom optics, physics of quantum degenerate gases, their mixtures, and atom interferometry. Our poster sketches the preliminary concepts and architecture, including the dimensions and estimated capabilities of the setup. [Preview Abstract] 

M01.00146: Towards BECborne twospecies atom interferometry in space Maike Diana Lachmann, Baptist Piest, Dennis Becker, Wolfgang Ertmer, Ernst M. Rasel Tests of the universality of free fall using twospecies atom interferometers in space are currently of large interest. By increasing the free evolution time in the interferometer due to the microgravity environment the sensitivity can be enhanced significantly. After the successful launch of the MAIUS1 mission and the first demonstration of BoseEinstein condensation in space we aim for twospecies atom interferometers on the sounding rocket missions MAIUS2 and 3. The new system contains, in addition to Rb87, K41 as a second species. It is planned to study mixtures as well as sequential and simultaneous interferometry using Raman beam splitters. One goal is to extend the free fall time during the interferometer to timescales that are not possible on ground. For this features like an optical dipole trap will be implemented. The developed technology and the studies on ground and during flight support future space missions with several applications. The poster will show the mission goals, the setup and the current progress on ground. [Preview Abstract] 

M01.00147: Atom sorting in a 3D optical lattice Aishwarya Kumar, TsungYao Wu, Felipe Giraldo Mejia, David S. Weiss We demonstrate perfectly filled 3D arrays of neutral atoms by moving individual atoms in a 3D lattice. Starting from a randomly halffilled 5x5x5 optical lattice of Cesium atoms, we implement the scheme proposed in Phys. Rev. A 70, 040302(R) (2004) in order to fill 5x5x2 and 4x4x3 sublattices. We start by imaging atoms with single site resolution, creating reliable occupancy maps, and projection sideband cooling the atoms so that they are in the vibrational ground state 89{\%} of the time. A sorting algorithm then calculates and implements a sequence of high fidelity targeted state flips and statedependent motion steps to fill a sublattice in real time. We achieve an average filling fraction of 0.96 and a perfect filling rate of 31{\%} (27{\%}) for a 5x5x2 (4x4x3) target sublattice. We have also characterized the errors in the sorting procedure and performed MonteCarlo simulations to study the scalability of this scheme. The sorting procedure reduces the total entropy of the system by a factor of 2.44 and is analogous to a Maxwell's demon. It also initializes a neutral atom quantum computer. [Preview Abstract] 

M01.00148: Controlling HHG spectra from LaguerreGaussian laser modes by spatial medium distribution Dmitry A. Telnov, ShihI Chu We study highorderharmonic generation (HHG) when the incident laser beam is in the LaguerreGaussian (LG) mode with a nonzero topological charge. Normally the harmonics are generated also in the LG mode with a nonzero topological charge, and their intensity vanishes on the beam axis. We find that the HHG signal in the central spot of the beam axis still can be detected if the spatial distribution of the medium in the focal region of the incident laser beam is inhomogeneous. Examples are discrete groups of atoms distributed symmetrically or nonsymmetrically on the circle with the highest laser intensity or the case when only a part of the circle is uniformly filled with the atoms. Manipulating the medium distribution, it is possible to control the shape of the HHG spectrum, switching on and off harmonics with particular orders or changing their intensity. General theoretical results are illustrated by calculations of HHG in the medium of argon atoms, with the singleatom response obtained by means of the timedependent density functional theory. [Preview Abstract] 

M01.00149: Optical cavity for enhanced parametric fourwave mixing in rubidium Erik Brekke, Sam Potier We have incorporated a ring cavity to enhance the efficiency of parametric fourwave mixing in rubidium. Using an input coupler with 95 percent reflectance, a finesse of 19.6 is achieved with a rubidium cell inside. This increases the circulating intensity by a factor of 5.6, and through twophoton excitation on the 5s$_{\mathrm{1/2}}$ to 5d$_{\mathrm{5/2\thinspace }}$transition with a single excitation laser, up to 1.9 mW of power at 420 nm is generated, 50 times what was previously generated with this scheme and comparable to low power twostep excitation. The dependence of the output on Rb density and input power has been explored, suggesting the process may be approaching saturation. The blue output of the cavity also shows greatly improved spatial quality, combining to make this a promising source of 420 nm light for future experiments. [Preview Abstract] 

M01.00150: MassEnergy Relationship Must Include Vibrational And Rotational Kinetic Energy Factors As Well As Potential Enery Factors Stewart Brekke Einstein originally proposed in his Special Theory of Relativity that at low speeds $E_0 = m_0c^2 + 1/2m_0v^2$. However, all kinetic and potential energies must be included in total energy consideration. A mass may also be rotating and/or vibrating as well and we must add the value of these kinetic energies to our calculations. Further, the values of all potential energies such as gravitational and electromagnetic potential energies must be added to the calculations for total energy consideration. If $[1/2I\omega^2]$ is the rotational kinetic energy expression. Also, if $[1/2kx^2]$ is a vibrational kinetic expression, we must add them. And if $[E_G= Gm_1m_2/r$ and $E_E_= kQ_1Q_2/r]$ are the equations for gravitational and electromagnetic potential energies respectively, the proper equation for the massenergy equivalence at low speed must be corrected to: $[E_0 = m_0 c^2 + 1/2m_0 v^2 + 1/2I\omega^2 + 1/2kx^2 + Gm_1m_2/r + kQ_1Q_2/r]$. [Preview Abstract] 

M01.00151: Tante CATO to Prodi Fisika ITB Widastra Hidajatullah As a matters of \underline {\textbf{terms substitutions,}} to \underline {siv.ostermangolkar@su.se} those were AS90873 Maori timesequences to 2018 to \textit{candida albicans } ATCC\textregistered 90873$^{\mathrm{TM\thinspace }}$ we retrieves \textit{``bukan TugasPangdam }\underline {\textbf{\textit{an sicht}}}\textit{\textellipsis }'' TanteCato {\&} Oom Frans/LiBelle1952/53 of ``mesiC ATOms'' $l = \quad L $[ 1  ( V$_{collapse}/$V)$^{\mathrm{2}}$] from Elwenspoek, \textit{et.al}: \textbf{``Static {\&} Dynamic Properties of Active Joints'',}\underline {TRANSDUCERS}, 1995 from whom quoted the comparisons between actuator {\&} strange attractor [fig 5 (a) sinusoidal input{\&} (c)] so there are wide roads between Nobuhiko Henmi harmonic amplitude hysteresis to description in 2001 from \textbf{HE. Mr. Prof. BSB }\textit{as cheap as } 2 x 1985 emits of US {\$} 1 delivers to Jl. LLRE Martadinata 46 in Oct2017 responds topographic {\&} magnetic survey of Pasirtomo gold ore. They correlates $n_{i}=\surd $[1  ($f_{k}/f)^{\mathrm{2}}$ ] \textless 1 from \textbf{HE. Mr. Prof. Liek WILARDJO's }``Gelombang Elektromagnetik'', h 114 explores first in the World's X18 tankboat established in Banyuwangi East\textunderscore Java \quad [Preview Abstract] 

M01.00152: The Comparison of Laser Therapy and Chemotherapy in the Treatment of Malignant Cancers Marysteven Uchegbu The term "laser"stands for light amplification by stimulated emission of radiation.Lasers are most commonly used to treat superficial cancers; such as Basel cell skin cancer and the very early stages of some cancers,such as cervical,penile, vaginal,vulvar,and nonsmall cell lung cancer.There are three types of lasers used to treat cancer:CO2 lasers, argon lasers,and Nd:YAG lasers.In contrast to the formers,the Nd:YAG laser is more commonly applied through an endoscope to treat internal organs. This work compared the use of laser therapy and chemotherapy. Chemotherapy is simply the use of chemicals to kill cancerous cells.To achieve this,the active ingredients of the chemicals,were studied as well as the pharmacokinetics and pharmacodynamics of the photosensitive drugs used during lasers.From findings made from patients,a conclusion was drawn that if lasers can be improved further,it will be more preferred than the use of chemotherapy. Reference http://www.cancer.gov./aboutcancer/treatment.National Cancer Institute. Viewed on 7/10/2016. [Preview Abstract] 

M01.00153: Signature of BCSBEC Crossover in an IronBased Superconductor FeSe$_{\mathrm{0.5}}$Te$_{\mathrm{0.5}}$. Shankar Kunwar Microscopic mechanism of superconductivity in highT$_{\mathrm{C}}$ superconductors has been one of the burning questions of condensed matter physics at the moment. Here, we present the scanning tunneling microscopy/spectroscopy (STM/STS) studies of an ironbased superconductor, FeSe$_{\mathrm{0.5}}$Te$_{\mathrm{0.5}}$ [1]. The value of superconducting order parameter $\Delta $, has been extracted from differential conductance (dI/dV) spectra with the help of extended Bardeen Cooper Schieffer (BCS) phenomenology for anisotropic swave pairing. The tunneling spectra are quite inhomogeneous with the values of $\Delta $ extended from $\sim $0.6 to $\sim $4.5 meV and have two distinct peaks in the histogram around 1 and 3 meV. The corresponding values of pairing strength, 2$\Delta $/k$_{\mathrm{B}}$T$_{\mathrm{C}}$ for the peaks are $\sim $1.5 and $\sim $5.0, respectively, which indicates the coexistence of weak and strong coupling mechanism. We also measured the gap to Fermi energy ratio ($\Delta $/E$_{\mathrm{f}}$ ) of the material and found two different regions of coupling inferring to the composite superconductivity in the realm of BCSBEC (Bose Einstein Condensate) crossover. [1] Kunwar S., et.al. J Supercond Nov Magn, 30, 3183 (2017). [Preview Abstract] 

M01.00154: Chiral orbital magnetism of $p$orbital bosons in optical lattices Bo Liu, Peng Zhang, Hong Gao, Fuli Li Chiral magnetism is a fascinating quantum phenomena that has been found in lowdimensional magnetic materials. It is not only interesting for understanding the concept of chirality, but also important for potential applications in spintronics. Past studies show that chiral magnets require both lack of the inversion symmetry and spinorbit coupling to induce the DzyaloshinskiiMoriya (DM) interaction. Here we report that the combination of inversion symmetry breaking and quantum degeneracy of orbital degrees of freedom will provide a new paradigm to achieve the chiral orbital magnetism. By means of the density matrix renormalization group (DMRG) calculation, we demonstrate that the chiral orbital magnetism can be found when considering bosonic atoms loaded in the $p$band of an optical lattice in the Mott regime. The high tunability of our scheme is also illustrated through simply manipulating the inversion symmetry of the system for the cold atom experimental conditions. [Preview Abstract] 

M01.00155: Detecting Thermal Acoustic Radiation with Mechanical Antenna Robinjeet Singh, Thomas Purdy We couple acoustic channels in and out of the membrane mechanical resonator to a remote mechanical bath. This work is in part an effort to understand external loss mechanism and further design new generation optomechanical absolute thermometers. [Preview Abstract] 

M01.00156: Timedependent Perturbation Propagator Norio Takemoto, B.D. Esry We develop a numerical method to solve the timedependent Schr\"{o}dinger equation based on timedependent perturbation theory. In this method, we expand a quantum state as a perturbation series and obtain a hierarchy of equations for the respective terms in the series. Each equation takes the form of an inhomogeneous timedependent Schr\"{o}dinger equation with the source term being the interaction potential multiplied by the solution of the lowerorder equation. The balance between efficiency and accuracy may be adjusted incrementally through the order of truncation, and timeordering of the propagator is exactly taken into account by setting the reference Hamiltonian to be timeindependent. The method allows us to interpret observables in terms of contributions of different perturbation orders. Furthermore, the solution at different values of the perturbation parameter can be computed without resolving the hierarchy of equations by simply resumming the perturbation series. Therefore, in application to lasermatter interactions, averaging over intensity or carrierenvelope phase (CEP) incurs negligible additional computational cost once the observables at a single intensity or CEP value are obtained. [Preview Abstract] 

M01.00157: Optical homodyne for pulsed lasers Katelyn Watson, Jonathan Mize, John Davis, J. Bruce Johnson A homodyne method is presented for determining the degree of coherence of laser pulses. The method was first tested using computer generated data with varying amounts of noise to test the accuracy of the method in the determination of the phase drift programmed into the pulses. Analysis of the computer generated data also revealed the degree of sensitivity to timing jitter between the laser pulses. In order to eliminate the timing jitter, all analysis was completed on individual laser pulses. This was done by splitting the laser pulse into four beams with two traversing a variable path length to introduce a delay. A delayed pulse was overlapped with a pulse without delay and directed onto the entrance slit of a streak camera. The other two pulses were also directed to the streak camera at locations separate from each other and the two overlapping pulses. Results are presented for a singlelongitudinalmode nanosecond laser and the frequencydoubled output from a Nd:YAG amplified picosecond Nd:YVO$_4$ modelocked oscillator. [Preview Abstract] 

M01.00158: Phase Tracking and Correction for Quantum Measurements of Coherent States Matthew DiMario, Elohim Becerra NonGaussian measurements for discriminating coherent states of light with different phases enable information transfer beyond what conventional technologies can achieve with an ideal Gaussian measurement, referred to as the standard quantum limit (SQL). However, random phase drifts in any realworld communication channel make the task of extracting the information encoded in coherent states very challenging. Current approaches for overcoming this problem in conventional optical communications based on heterodyne detection, which samples the full phase space, perform parameter estimation in the digital domain for phase estimation. While these techniques allow for tracking and correction of random phase drifts in conventional communications, they are incompatible with nonGaussian (quantum) receivers. This puts in question the potential advantages of quantum receivers surpassing the conventional limits of detection in real channels with random phase drifts. We develop and demonstrate a method which performs real time parameter estimation using the data collected by the nonGaussian optimized discrimination measurement itself. We can then adaptively correct for any phase changes that diminish the benefit over a heterodyne measurement. Our demonstration allows nonGaussian receivers to overcome phase drifts in real channels while enabling discrimination below SQL. This demonstration makes nonGaussian receivers more robust and a much more practical quantum technology for future applications in communication and information processing. [Preview Abstract] 

M01.00159: Engineering programmable spin interactions in a trapped ion quantum simulator with holographic singleion addressing ChungYou Shih, Fereshteh Rajabi, Ashok Ajoy, Kaleb Ruscitti, Nikhil Kotibhaskar, Sainath Motlakunta, Nikolay Videnov, Ilango Maran, Rajibul Islam Trapped ions are an ideal platform for quantum simulation of manybody spin Hamiltonians. To engineer arbitrary spinspin interaction graphs, we need arbitrary addressing of individual spins. Here, we demonstrate holographic beam shaping using a digital micromirror device (DMD) for individually manipulating Yb+ ion spins and interactions between spin pairs. A precise optical intensity gradient will allow us to control individual spin phases, which can modify global MolmerSorensen interactions to realize the target interaction graph, in a hybrid analogdigital quantum simulation. This method of individual addressing is a scalable alternative for a long inhomogeneously spaced ion chain compared to other approaches that rely on scanning a tightly focused laser beam, or on devices that produce a fixed number of equally spaced laser beams. [Preview Abstract] 

M01.00160: Photoionzation dynamics of Ar and K$+$\textbf{ trapped inside fullerenes} Hari Varma Ravi, Afsal Thuppilakkadan Wigner photoionization time delay studies are found to be a powerful tool to understand photoionization dynamics of atoms trapped inside fullerenes [1, 2, 3]. In this work, we report theoretical photoionization studies of Ar and K$^{\mathrm{+}}$trapped inside neutral and in charged fullerenes exploring the role of electron correlation and confinement effects along the isoelectronic sequence. The external cages are modeled by spherical potentials as reported in literature [3, 4]. The well known relativistic random phase approximation [5] is employed to obtain the cross section and the Wigner time delay. The polarization effects are not included in the present work as it is a preliminary study in this direction.It is found that the presence of confinement induces different effects on the cross section and on the time delay spectrum of Ar and K$+$ especially near the threshold region. [1] Pazourek et al., Rev. mod. phy. 87 765 (2015). [2] P. C. Deshmukh et al., Phys. Rev. A 89, 053424 (2014). [3] A. Kumar et al., Phys. Rev. A 94, 043401 (2016). [4] V.K. Dolmatov, S. T. Manson, Phys. Rev. A 73, 013201 (2006). [5] W. R. Johnson and C. D. Lin., Phys. Rev. A 20, 964 (1979) [Preview Abstract] 

M01.00161: Light Stops at Exceptional Points Tamar Goldzak, Alexei A. Mailybaev, Nimrod Moiseyev Almost twenty years ago, light was slowed down to less than 10 − 7 of its vacuum speed in a cloud of ultracold atoms of sodium. Upon a sudden turnoff of the coupling laser, a slow light pulse can be imprinted on cold atoms such that it can be read out and converted into a photon again. In this process, the light is stopped by absorbing it and storing its shape within the atomic ensemble. Alternatively, the light can be stopped at the band edge in photoniccrystal waveguides, where the group speed vanishes. Here, we extend the phenomenon of stopped light to the new field of paritytime ( P T ) symmetric systems. We show that zero group speed in P T symmetric optical waveguides can be achieved if the system is prepared at an exceptional point, where two optical modes coalesce. This effect can be tuned for optical pulses in a wide range of frequencies and bandwidths, as we demonstrate in a system of coupled waveguides with gain and loss. [Preview Abstract] 

M01.00162: Efimov Physics in Quenched Unitary Bose Gases Jose D'Incao, Jia Wang, Victor Colussi We study the threebody physics in quenched unitary Bose gases, focusing on signatures of the Efimov effect in macroscopic observables. Using a localdensity model, we solve the threebody problem and determine threebody decay rates at unitary, finding densitydependent, logperiodic oscillations characteristic of the Efimov effect. These oscillations violate the continuous scaling invariance in the problem. Studying the earliest stages of evolution after quenching the interaction to unitarity, we find the growth of a substantial population of Efimov states for densities beyond where the interparticle distance is comparable to the size of an Efimov state. This finding is consistent with a recent analysis by Colussi {\em et al.} [1] on the earlytime dynamical growth of threebody correlations at unitarity By varying the sweep rate away from unitarity, we find a departure from the usual LandauZener analysis for the formation of states within the nonequilibrium regime. [1] V. E. Colussi, J. P. Corson, and J. P. D’Incao, arXiv:1710.10580 [Preview Abstract] 
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