Bulletin of the American Physical Society
50th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 64, Number 4
Monday–Friday, May 27–31, 2019; Milwaukee, Wisconsin
Session E01: Poster Session I (4:00pm6:00pm) 
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Room: Wisconsin Center Hall A 

E01.00001: COLLISIONS AND SPECTROSCOPY 

E01.00002: Longrange asymptotic behaviour of the exchange energy in the hydrogen molecule Michal Silkowski, Krzysztof Pachucki The exchange energy is of fundamental importance for the understanding of interatomic interactions. Its longrange behavior in H$_2$ was investigated in the early days of quantum mechanics\footnote{W. Heitler and F. London, Z. Physik \textbf{44}, 455 (1927)}. Those results were met with criticism\footnote{C. Herring, Rev. Mod. Phys. \textbf{34}, 631 (1962)} and asymptotically correct form was derived by Herring and Flicker\footnote{C. Herring and M. Flicker, Phys. Rev. \textbf{134}, A362 (1964)}. Despite further work by many authors\footnote{K. T. Tang, J. Peter Toennies, and C. L. Yiu, J. Chem. Phys. \textbf{99}, 377 (1993)}\textsuperscript{,}\footnote{B. L. Burrows, A.~Dalgarno, and M. Cohen, Phys. Rev. A \textbf{86}, 052525 (2012)}, longrange asymptotics of exchange energy in H$_2$ still raises controversy. \\ We present highprecision variational calculations of energy splitting between the lowest hydrogen states performed with our H2SOLV\footnote{K. Pachucki, M. Zientkiewicz, V.A. Yerokhin, Comput. Phys. Commun. \textbf{208}, 162 (2016)} package, which utilizes explicitly correlated exponential basis\footnote{K. Pachucki, Phys. Rev. A \textbf{88}, 022507 (2013)}. Due to correct asymptotic behavior of our basis, we claim that our numerical results resolve this controversy. [Preview Abstract] 

E01.00003: Nuclearstructure effects in muonic deuterium Marcin Kalinowski, Krzysztof Pachucki, Vladimir Yerokhin Muonic deuterium is a subject of intense study due to the sensitivity of its spectrum to the electromagnetic moments of the nucleus. However, nuclearstructure effects make precise theoretical description of energy levels much harder than in the case of hydrogen. Recently, we've completed a systematic calculation of the leading nuclear polarizability contribution to the hyperfine splitting of the 2S state in muonic deuterium. Our result disagrees with the previous calculations and differs by 5 standard deviations from the experimental value. It suggests that the spindependent nuclear polarizability is not well understood. We have also calculated the electron vacuum polarization correction to the leading nuclearstructure contribution to the Lamb shift in muonic deuterium. This correction is surprisingly large and modifies the value of the deuteronproton chargeradii square difference, which is consistent with the priecise value obtained from the ordinary HD isotope shift in the 1S2S transition. This agreement is a strong evidence that the chargeradii values obtained from the measurements of muonic deuterium and muonic hydrogen are correct. It suggests that any occuring discrepancies with electronic systems are due to their underestimated uncertainties. [Preview Abstract] 

E01.00004: Electron Affinity of Thallium Measured with Infrared Laser Photodetachment Threshold Spectroscopy C.W. Walter, N.D. Gibson, K.R. Patel, S.E. Spielman The electron affinity of thallium has been measured using tunable infrared laser photodetachment threshold spectroscopy. The relative cross section for neutral atom production following photodetachment from Tl$^{}$ was measured with a crossed laserion beam apparatus over the photon energy range 0.30  0.90 eV. An \textit{s}wave threshold was observed due to the opening of the Tl$^{}$ (6\textit{p}$^{2}$ $^{3}$\textit{P}$_{0}$) to Tl (6\textit{p} $^{2}$\textit{P}$_{1/2}$) groundstate to groundstate transition, yielding a preliminary value for the electron affinity of thallium. No photodetachment signal was detected below this threshold and no other thresholds were observed over the present photon energy range, leading to the conclusion that the fine structure excited states of Tl$^{}$ are not bound. The present results are compared with previous experimental [1] and theoretical [2] studies of Tl$^{}$. \\[4pt] [1] D. L. Carpenter, A. M. Covington, and J. S. Thompson, \textit{Phys. Rev. A} \textbf{61}, 042501 (2000); [2] see for example J. Li, Z. Zhao, M. Andersson, X. Zhang, and C. Chen, \textit{J. Phys. BAt. Mol. Opt. Phys.} \textbf{45}, 165004 (2012). [Preview Abstract] 

E01.00005: Towards a selfconsistent approach to model cool hydrogen plasma emission Mark Zammit, James Colgan, Jeremy Savage, Dmitry Fursa, Igor Bray, Christopher Fontes, David Kilcrease, Peter Hakel, Jeffery Leiding, Eddy Timmermans Cool (molecular) plasmas are ubiquitous throughout the Universe. Practically all opacity and emissivity studies of molecular plasmas are conducted utilizing data or codes taken from several different sources. To this end, we are developing a fully generalizable selfconsistent approach to model cool hydrogen (H$_2$ and H$_2^+$) plasmas opacity and emissivity. Here we present results of cool hydrogen plasmas emission, and a preliminary investigation of the plasma effects in lowtemperature hydrogen plasmas using an equation of state model. [Preview Abstract] 

E01.00006: Undergraduate Research Project on Characterization of Quantum Interference in Spontaneous Emission in an Atomic Gas with a Single Pulsed Laser Matthew Wright, Julianna Yee, Olivia Chierchio We are currently investigating the quantum interference in spontaneous emission in a dilute thermal atomic gas with an intense pulsed laser beam. A short pulse of the light (\textasciitilde 6 ns) is used to excite Rb atoms in a roomtemperature cell. During the exponential decay, we have been able to detect a quantum beat which is consistent with the hyperfine levelsplitting of the excited state manifold. We plan to investigate how these beats vary on frequency, polarization, and other laser parameters. [Preview Abstract] 

E01.00007: Monte Carlo study of alternative Xray sources and Kalpha resonance fluorescence for enhancing radiation therapy Maximillian Westphal, Sultana Nahar, Anil Pradhan Using the Monte Carlo code GEANT4 we have studied alternative Xray sources as well as a variety of nanoparticles as a method to improve tumor irradiation and cancer theranostics (therapy and diagnostics). We used GEANT4 to simulate photons from quasimonochromatic (QX), monochromatic (MX), and traditional broadband (BX) medical Xray sources interacting with heavy element nanoparticles designed to enhance Xray absorption [1]. A combined experimental, theoretical, and numerical study of Zr K$_{\alpha,\beta}$ fluorescence and scattering is presented. Simulations of resonant nanoplasma states driven by highintensity K$_{\alpha}$ radiation is carried out [2], with nanoparticles of gold, platinum, or gadolinium in sizes from 220 nm, and shapes including rods, spheres, and cubes. \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] 

E01.00008: Experimental Study of the 3$^{\mathrm{1}}\Pi_{\mathrm{g}}$ , 5$^{\mathrm{1}}\Sigma_{\mathrm{g}}^{\mathrm{+}}$, and 6$^{\mathrm{1}}\Sigma_{\mathrm{g}}^{\mathrm{+\thinspace }}$States of Rubidium Dimer Phillip Arndt, Vladimir Sovkov, Jie Ma, Xinhua Pan, David Beecher, Jeng Tsai, Yafei Guan, Marjatta Lyyra, Ergin Ahmed The structure of the excited electronic states of Rubidium dimer is important to a number of areas of research including the production of ultracold ground state molecules, cold atommolecule collisions, and the development of new \textit{ab initio} molecular electronic structure methods. In the experiment we used optical double resonance technique to observe large number of rovibrational levels of the 3$^{\mathrm{1}}\Pi_{\mathrm{g}}$ , 5$^{\mathrm{1}}\Sigma_{\mathrm{g}}^{\mathrm{+}}$, and 6$^{\mathrm{1}}\Sigma_{\mathrm{g}}^{\mathrm{+}}$ electronic states in the 2400026000 cm$^{\mathrm{1}}$ range. The set of term values for each state were simulated within a model of a piecewise multiparameter potential energy function based on the generalized splines. This function reproduces the experimental data for each state with reasonable accuracy and in addition allows us to incorporate in the potential function the nontrivial features at longer internuclear range, such as multiple wells, predicted by the \textit{ab initio }calculations. [Preview Abstract] 

E01.00009: Radiative lifetimes of the 4$^{\mathrm{1}}\Sigma _{\mathrm{g}}^{\mathrm{+}}$ state of Na$_{\mathrm{2}}$ Nadeepa Jayasundara, Lutz Hüwel, Seth Ashman We present both experimental and calculation results for lifetimes of some rovibrational levels of the Na$_{\mathrm{2}}$ 4$^{\mathrm{1}}\Sigma _{\mathrm{g}}^{\mathrm{+}}$ shelf state. Ground state Na$_{\mathrm{2}}$ molecules in a mild supersonic molecular beam are excited to populate the selected rovibrational levels in the 4$^{\mathrm{1}}\Sigma _{\mathrm{g}}^{\mathrm{+}}$ state using double resonance excitation via the intermediate A$^{\mathrm{1}}\Sigma_{\mathrm{u}}^{\mathrm{+}}$ state. Then, the excited molecules are ionized from a delayed Nd:YAG laser and the generated ions are detected in a linear timeofflight mass spectrometer. By changing the probe laser delay, lifetimes are extracted for individual rovibrational levels. The lifetimes of each rovibrational level were calculated using the LEVEL 8.2 and BCONT programs by Robert Le Roy, the latter in a version modified by Brett McGeehan. We find that radiative lifetimes of the 4$^{\mathrm{1}}\Sigma_{\mathrm{g}}^{\mathrm{+}}$ state vary with vibrational level, mainly around the shelf region. Furthermore, we observe a strong oscillatory radiative lifetime variation with rotational levels for fixed vibrational levels. We also offer an explanation for the unusual rotational level dependence which might exist, according to our reasoning, in other electronic states with a shelf or double wells. [Preview Abstract] 

E01.00010: Search for optical emission from the Th 229m lowlying nuclear state Randy Knize, Mark Lindsay, Matthew Rotondaro We conducted an experiment to measure the energy and lifetime of the VUV optical transition from the Th 229m nuclear excited state to the ground state (transition energy estimated to be 7.8 eV). Many groups over the past decades have attempted to spectroscopically detect this lowest energy nuclear excited state. If its lifetime is long as expected, this state could function as a very isolated long coherence time qbit, and it could be extremely important as an ultranarrow clock transition for time metrology. We used a 15 nm thick film of highly purified U 233 source to implant Th 229m ions in the surfaces of substrates of CaF2, MgF2, and sapphire. We measured the time decay over 15 hours of the resulting VUV fluorescence and phosphorescence photons, with energy resolution provided by a series of bandpass interference filters over a range of 140 to 240 nm. We also measured photons coming from the implanted Th without time delay, as a function of the energy. These results are compared with a control experiment having the Th ions blocked by thin films, but the large background of alphas and betas still let through. [Preview Abstract] 

E01.00011: Precision Measurements of Excited State Atomic Lifetimes in Rb and K Jerry Sell, Brian Patterson, Alina Gearba, Mark Lindsay, Derald Madson, Jeremiah Wells, Jeremy Snell, Randy Knize Measurements of excited state atomic lifetimes are presented for the rubidium $5P_{3/2}$ state and the potassium $4P_{3/2}$ state using a combination of continuous and ultrafast lasers. These measurements provide the associated transition dipole matrix element, which can be compared to theoretical calculations. Additionally, these results can be used in combination with polarizability and tuneout wavelength measurements to further constrain atomic parameters and test atomic theory. The experimental apparatus to carry out these measurements employs counterpropagating atomic beams and a pumpprobe (excitationionization) technique based on a modelocked ultrafast laser. We will discuss the various systematic errors which are present in our measurements. [Preview Abstract] 

E01.00012: Photoionization of the CO Molecule J. P. Colgan, M. S. Pindzola A configurationaverage distortedwave method is used to calculate the photoionization cross section for the CO molecule. The valence bound molecular orbital is found from HartreeFock calculations for CO, while the potential for the ejected electron is found from HartreeFock calculations for CO+. The cross sections are compared with Rmatrix calculations and experiment. [Preview Abstract] 

E01.00013: Benchmark calculations for photoionization of neutral iron from the ground and excited states. Oleg Zatsarinny, Klaus Bartschat, Luis FernandezMenchero, Swaraj S. Tayal The $B$spline $R$matrix method [1,2] is used to investigate the photoionization of neutral iron from the ground and excited states in the energy region from the ionization thresholds to 2 Ry. The multiconfiguration HartreeFock method in connection with adjustable configuration expansions and termdependent orbitals is employed for an accurate representation of the initial states of Fe I and the target wave functions of Fe II. The closecoupling expansion contains 261 $LS$ states of Fe II and includes all levels of the $3d^64s$, $3d^54s^2$, $3d^7$, $3d^64p$, and $3d^54s4p$ configurations. Full inclusion of all terms from the principal configurations considerably changes both the lowenergy resonance structure and the energy dependence of the background cross sections. Partial cross sections are analyzed in detail to clarify the most important scattering channels. Comparison with other recent calculations such as [3] is used to place uncertainty bounds on the predicted photoionization cross sections and to assess the likely uncertainties in the existing data sets. [1]~O. Zatsarinny, Comp. Phys. Comm. {\bf 174} (2006) 273. [2] O. Zatsarinny and K. Bartschat, J. Phys. B {\bf 46} (2013) 112001. [3] M. A. Bautista, K. Lind, and M. Bergemann, A \& A {\bf 606} (2017) A127. (2017). [Preview Abstract] 

E01.00014: Photoionization of the openshell nitrogen atom confined in C$_{60}$ T. W. Gorczyca, S. T. Manson Since almost all of the work on the response of confined atoms to ionizing radiation has considered closedshell atoms [1], we have embarked on a program to investigate the response of openshell atoms with confinement. To this end, calculations of the photoionization of each of the three states, $^4$S, $^2$D and $^2$P, arising from the ground 1s$^2$2s$^2$2p$^3$ configuration of the nitrogen atom confined in C$_{60}$, N@C$_{60}$, have been performed using a variation of the Belfast Rmatrix code that we have modified to simulate the confinement [2], from the thresholds to a photon energy of 29 eV. For comparison, free atom calculations have also been done using the same methodology. The results show that the confinement has very significant effects on the cross sections, both in resonance regions and in the open continuum, both qualitatively and quantitatively. Lowenergy confinement resonances are clearly seen. In addition, the $^4$S cross sections (confined and free) are rather different from their $^2$D and $^2$P counterparts owing to the significant differences between the quartet and doublet final continuum states. [1] V. K. Dolmatov, Adv. Quantum Chem. 58, 13 (2009); [2] T. W. Gorczyca, M. F. Hasoglu, and S. T. Manson, Phys. Rev. A 86, 033403 (2012). [Preview Abstract] 

E01.00015: Theoretical Studies of Dissociative Recombination of Electrons with SH$^+$ Ions D.~O. Kashinski, J.~T. Bohnemann, A.~P. Hickman, D. Talbi We are investigating the dissociative recombination (DR) of electrons with the molecular ion SH$^+$, i.e. $e^ + \mathrm{SH}^+ \rightarrow \mathrm{S + H}$. SH$^+$ is found in the interstellar medium (ISM), and its chemistry is still not fully understood. Understanding the role of DR of electrons with SH$^+$ will lead to more accurate astrophysical models. Recently we addressed the $^2\Pi$ potential energy curves (PECs) of SH as a DR pathway \footnote{Kashinski, Talbi, Hickman \emph{et al.}, J.\,Chem.\,Phys. \textbf{146}, 204109 (2017)}. We are extending this work to investigate the ground and excited $^4\Pi$ PECs of SH as an alternate DR pathway. Large activespace multireference configuration interaction (MRCI) electronic structure calculations were performed using the GAMESS code to obtain the PECs for several values of SH separation. Rydbergvalence coupling has proven to be important. The block diagonalization method was used to disentangle interacting states and form a diabatic representation of the PECs. The status of this ongoing work will be presented at the conference. [Preview Abstract] 

E01.00016: DFT Calculation of the Renner Coefficient for the RennerTeller Splitting in the NCO radical: Assessing the accuracy of several common functional families and basis sets D.~O. Kashinski, M.~G. Suarez, C.~C. Stephens, E.~F.~C. Byrd The ``out of box'' DFT calculation of the Renner coefficient for the RennerTeller splitting in the NCO radical using functionals from the B3LYP, PBE, TPSS, M06, and M11 functional families with standard Correlation Consistent ccpV$x$Z and augccpV$x$Z ($x=$ D, T and Q), 6311G split valence family, as well as Sadlej, and Sapporo polarized triple$\zeta$ basis sets is being completed. Quantum chemistry calculations are being completed using the GAUSSIAN16 suite on DoDHPCs. A comparison of our results to previously published theoretical and experimental results has been tabulated to assess the accuracy of the functional and basis set combination. The impact of functional and basis set choices on the resulting coefficients is being characterized. An update on the progress of this work will be given at the meeting. Early work on other linear triatomics will also be presented. [Preview Abstract] 

E01.00017: Using a MagnetoOptical Trap (MOT) to teach Experimental and Computational Methods in Undergraduate Physics D.~O. Kashinski, L.~E. Harrell, K. Ingold, M. Cassidy, C.~S. Gerving Experimental physics programs at primarily undergraduate institutions are often unable to include experimental atomic physicsspecifically cold atom experimentsas part of the curriculum. At the United States Military Academy we are using coldatom physics as the motivation for our culminating seniorlevel ``Experimental Methods in Physics'' course. Students first learn computational methods to numerically solve a range of problems including % from the classical damped harmonic oscillator to the the equations describing the motion of atoms in a MOT. After an extensive literature review and basic laboratory instruction the studentteams endeavor to create a basic MOT. Previous experimental and theoretical coursework is reinforced through the handson setup of the cooling and repump laser systems and use of saturated absorption spectroscopy to observe the hyperfine structure of Rb. The experiment culminates with the appropriate laser light being combined in a vacuum chamber forming a MOT of $^{87}$Rb. If time permits, students then characterize the MOT of $^{87}$Rb comparing their results to simulations. The outcome of this new course will be presented at the meeting. [Preview Abstract] 

E01.00018: The Iron Project \& The Opacity Project: 1. Photoionization of Fe ions for Opacities, 2. P II in exoplanetary environments W. Eissner, L. Zhao, S. Nahar, A. Pradhan 1. At the radiative and convection boundary in the Sun iron opacity depends on Fe~XVIIFe~XIX. With the aim of resolving the outstanding discrepancy in theoretical solar iron opacity and measurements at the Sandia Zpinch ICF device, largescale calculations for photoionization cross sections and transition probabilities have been carried out using the BreitPauli RMatrix (BPRM) method, including the heretofore neglected autoionization resonance features and resulting opacity enhancement. Fe~XVII BPRM calculations include 218 coupled fine structure levels in the Fe~XVIII target wavefunction expansion, and Fe~XVIII calculations include 276 levels of Fe~XIX. It is found that huge Seaton resonances due to photoexcitationofcore (PEC) make the dominant contribution to boundfree opacity. Hitherto, these are among the most complex RMatrix calculations. Convergence and completeness of coupled channel calculations is also addressed. 2. Phosphorus is one of the elements of DNAbased lifeforms. Its abundance in exoplanetary environments may indicate spectral biosignatures. We will report new BPRM calculations for collisional data for P~II and predicted spectrum of P~II in the wavelength region of interest. [Preview Abstract] 

E01.00019: Plasma screening effect on atomic collisions in turbulent plasmas YoungDae Jung, MyoungJae Lee The plasma screening effect on the electronion collision is investigated in nonthermal turbulent plasmas. The secondorder eikonal analysis and the effective interaction potential including the Lorentzian farfield term are employed to obtain the eikonal scattering phase shift and the eikonal collision cross section as functions of the diffusion coefficient, impact parameter, collision energy, Debye length and spectral index of the Lorentzian plasma. It is shown that the nonthermal effect suppresses the eikonal scattering phase shift. However, it enhances the eikonal collision cross section in astrophysical nonthermal turbulent plasmas. The effect of nonthermal turbulence on the eikonal atomic collision cross section is weakened with increasing collision energy. [Preview Abstract] 

E01.00020: Studies of Collision Dynamics in Rb SpinExchange Cells K.J. Ahrendsen, W.J. Brunner, T.J. Gay We report the most recent advances in the development of a novel source of spinpolarized electrons: the Rb spin filter [1]. Polarized electron beams are produced by electrostatically driving an unpolarized beam of thermionically emitted electrons through a cell containing a mixture of opticallypumped Rb vapor (n $=$ \textasciitilde 10$^{\mathrm{13}}$ cm$^{\mathrm{3}})$ and N$_{\mathrm{2}}$ buffer gas (n $=$ \textasciitilde 10$^{\mathrm{16}}$ cm$^{\mathrm{3}})$. Previous studies of this process produced the unexpected result that the largest quantity of spinpolarized electrons are produced when the unpolarized electrons are incident on the spinexchange cell at an energy of 50  100 eV, as opposed to energies \textless 5 eV [2]. We hypothesize that this occurs because the maximum of the cross section for the ionization of nitrogen by electron impact occurs in this energy range, and that the slow, ionized electrons more effectively exchange spins with the Rb than do slow incident electrons. We report further investigations of this phenomenon, including a MonteCarlo simulation of the collision cell dynamics. [1] H. Batelaan \textit{et}. \textit{al}., Phys. Rev. Lett. \textbf{82}, 4216 (1999). [2] M. Pirbhai \textit{et}. \textit{al}., Phys. Rev. A \textbf{88}, 060701(R) (2013). [Preview Abstract] 

E01.00021: State changing through verylongrange interactions in high$n$, $n \ge $ 300, RydbergRydberg collisions Shuhei Yoshida, J. Burgdorfer, Robert Fields, Robert Brienza, F.B. Dunning State changing in thermalenergy collisions between atoms in veryhigh$n$, $n$ $\ge $ 300, Rydberg states is studied by observing the quantum beats induced by sudden application of a small dc electric field. These socalled Stark beats are shown to be sensitive to angular momentum L and are used to probe the evolution of L during collisions. The data show that, even for impact parameters as large as 50 $\mu $m, collisions lead to rapid Lchanging highlighting the longrange nature of the interactions responsible. The corresponding Lchanging cross sections are large, 10$^{\mathrm{4}}$ cm$^{\mathrm{2}}$, and much greater than the ``hardsphere'' cross sections 4$\pi $r$^{\mathrm{2}}$, where r $\approx n^{\mathrm{2}}$ is the atomic radius. The results also show that measurements of quantum beat amplitudes can provide a valuable complement to selective field ionization when investigating statechanging reactions. [Preview Abstract] 

E01.00022: Low energy scattering properties in cold Littium7 and Rubidium87 mixtures Fang Fang, Joshua Isaacs, Aaron Smull, Shun Wu, Dan StamperKurn We report measurements of interspecies interaction strength between Littium7 and Rubidium87, both in spherical quadruple magnetic trap and in optical dipole trap. In the former case, we present measurements of equilibration rates for littium7 in Rubidium87 reservoir undergoing crossdimensional relaxation. Thanks to the high mass imbalance between Li and Rb, as well as the nonergodicity nature of spherical quadruple trap, we are able to measure the small interspecies cross section at a collisional energy of hundreds of microKelvin. In the latter case, we measure the spindependent interaction in the cold mixture trapped in a spinindependent optical dipole trap at a collisional energy of tens of microKelvin. In the end, we will present our progress towards a new apparatus for Littium7 and Rubidium87$_{\mathrm{\thinspace }}$ultracold molecule. [Preview Abstract] 

E01.00023: Coupledchannels analysis of Feshbach resonances in a Mott insulator Thomas Secker, Servaas Kokkelmans Ultracold atomic gas experiments have proven to be a versatile ground for studying quantum mechanics, quantum manybody physics, quantum simulation and computation. A precise model for twobody collisions in those systems is essential. Coupledchannels models can accurately describe the twoatom system at ultracold temperatures by detailed interaction potentials that are finetuned by just a few parameters, determined from experiment. We extend such a coupledchannels model to include the situation in a Mott insulator phase of ultracold bosonic atoms, where two atoms are confined to one lattice site. Of particular importance is the specific conversion between the onsite interaction energy, which remains finite in the lattice, and the scattering length around a Feshbach resonance that diverges. Recently spectroscopic techniques allowed for a precise experimental determination of the onsite interaction energy in a system of $^7$Li atoms \footnote{J. AmatoGrill, N. Jepsen, I. Dimitrova, W. Lunden, W. Ketterle, arXiv:1809.06891 [condmat.quantgas] (2018).}, we analyze this data with our model to improve the precision of current lithium interaction potentials. [Preview Abstract] 

E01.00024: \textbf{Study of the effect of collisions on the rotational angular momentum of diatomic molecules with polarized light} Phillip Arndt, Charles Packard, Vy Tran, Joshua Carey, Rebecca Livingston, John Huennekens, Marjatta Lyyra, Ergin Ahmed Understanding the underlying mechanisms of collisional processes between atoms and molecules is of fundamental importance for a large number of areas of research, including chemical reactivity, ultracold atoms and molecules, and astrophysics of the interstellar medium. In general, molecules are not spherically symmetric objects and as a result most collisional processes involving them strongly depend on the relative alignment of the colliding partners. We have studied experimentally the changes in the alignment of the rotational angular momentum of diatomic molecules during elastic and inelastic collisions. In the experiment we use a system consisting of diatomic lithium molecules colliding with noble gas atoms (helium and argon) in a thermal gas phase sample. The collisions are studied in the first excited A$^{\mathrm{1}}\Sigma_{\mathrm{u}}^{\mathrm{+}}$ state using combination of polarized laser light and fluorescence to selectively excite and detect the molecules in specific rotational sublevels. [Preview Abstract] 

E01.00025: ElectronImpact Ionization of Kr C. J. Favreau, M. S. Pindzola A timedependent closecoupling method is used to calculate the electronimpact ionization cross section for the Kr atom. The valence bound orbital is found from HartreeFock Relativistic calculations for Kr, while the potential for the scattered and ejected electrons is also found from HartreeFock Relativistic calculations for Kr. The cross sections are compared with timeindependent distortedwave calculations and experiment. [Preview Abstract] 

E01.00026: Effect of cascade transitions after electronimpact excitation of Zn by spinpolarized electrons. Klaus Bartschat, Oleg Zatsarinny, Dmitry Fursa, Christopher Bostock, Igor Bray, Alexei N. GrumGrzhimailo We investigate the possible effect of cascade transitions from the $(4s5p)^3P_{0,1,2}$ states to the $(4s5s)^3S_1$ state of Zn. The polarization of the light emitted in the subsequent decay to the $(4s4p)^3P_{0,1,2}$ states has been the subject of recent controversy, with significant disagreement between the experimental data reported by Pravica {\it et al.}~[1] and by Clayburn and Gay~[2] in the cascadefree region below $\approx 7.6$~eV incident energy and relatively good agreement above. The cross sections for excitation of the $(4s5p)^3P_{0,1,2}$ states and the linear polarization of the cascade radiation seem too small to produce a significant alignment of the $(4s5s)^3S_1$ state, thereby raising additional questions regarding the origin of the relatively large linear polarizations measured above the cascade threshold. [1] L.~Pravica {\it et al.}, Phys. Rev. A {\bf 83} (2011) 040701). [2] N.~B.~Clayburn and T.~J.~Gay, Phys. Rev. Lett. {\bf 119} (2017) 093401. [Preview Abstract] 

E01.00027: New insights in negative ion formation in atomic Pu Zineb Felfli, Alfred Z Msezane We probe the response to lowenergy electron collision with atomic Pu through the elastic total cross sections (TCSs) calculation and find them to exhibit both atomic and molecular character as was discovered for the fullerene molecules [1]. They also exhibit the size effect through the creation of a new polarizationinduced metastable TCS with anionic binding energy value of 1.22 eV close to that of the first metastable negative ion at 1.57 eV. The calculations were carried out using our robust Reggepole methodology which embeds the crucial electronelectron correlation effects and the vital core polarization interaction; these are the major physical effects that are responsible for stable negative ion formation in lowenergy electron collisions with complex heavy systems. The identification of the ground state binding energy (BE) of the formed negative ion during the collision provides a new approach to the definitive determination of the theoretically challenging to calculate EAs of complex heavy systems. The extracted ground state anionic BE located at the second RamsauerTownsend (RT) minimum viz. 3.25 eV is largest BE of the previously investigated actinide atoms, including the U atom [2]. The Pu TCSs will be contrasted with those of the U atom, while the BEs will be compared with those from other calculations. These results demonstrate the importance of the delineation and identification of the resonance structures in the near threshold electron scattering TCSs, particularly the ground state anionic BEs. 1. A. Z. Msezane and Z. Felfli, Chem. Phys. \textbf{503}, 50 (2018); 2. Z. Felfli and A. Z. Msezane, Applied Physics Research Vol. \textbf{11}, No. 1 (2019). doi:10.5539/apr.v8n1pxx [Preview Abstract] 
(Author Not Attending)

E01.00028: Perfluorination Effect through Computation of Electron Scattering Cross sections for Hexafluoroacetone (HFA) and Acetone Molecules U R Patel, H N Kothari, K N Joshipura Electron molecule scattering processes play an important role in the understanding of the electron driven physiochemical phenomena in diverse environments such as biological media, planetary atmospheres, interstellar clouds and plasmas. In modeling and simulating effects induced by electrons traversing through matter, the relevant cross section data are required as an input. In present work we discussed a semi empirical approach i.e. Complex Scattering Potential method to obtain various electron scattering cross sections for molecules. The method has been tested for wide flavors of atoms and molecules$^{\mathrm{13}}$. We report total elastic ($Q_{el})$, total inelastic ($Q_{inel})$ and total cross sections ($Q_{T\thinspace }=Q_{el}+Q_{inel})$ for (CF$_{\mathrm{3}})_{\mathrm{2}}$CO and (CH$_{\mathrm{3}})_{\mathrm{2}}$CO. Further total ionization cross sections ($Q_{ion})$ are extracted from total inelastic ($Q_{inel})$ cross sections. Calculated results are compared with measured/calculated cross sections of Szmytkowski\textit{ et. al}$^{\mathrm{4}}$. Present results have good accord with available results and Perfluorination effect is discussed. $^{\mathrm{1}}$Patel \textit{et. al} J. Chem. Phys. \textbf{140} 044302 (2014), $^{\mathrm{2}}$Joshipura \textit{et.al} Phys. Rev. A, \textbf{69} (2004) 022705, $^{\mathrm{3}}$Joshipura \textit{et. al, }Phys. Lett. A,\textbf{ 373} (2009) 2876, $^{\mathrm{4}}$Szmytkowski\textit{ et. al} J. Phys. B: At. Mol. Opt. Phys. \textbf{44} (2011) 205202. [Preview Abstract] 

E01.00029: Dissociative recombination of CH$_2$NH$_2^+$ and NH$_2$CH$_2$O$^+$ ions Viatcheslav Kokoouline, Chi Hong Yuen, Ioan Schneider, Cecilia Ceccarelli, Nadia Balucani, Mehdi Ayouz Cross sections for dissociation recombination (DR) and vibrational excitation of the CH$_2$NH$_2^+$ and NH$_2$CH$_2$O$^+$ ions in collisions with electrons are determined theoretically using an approach that combines the normal modes approximation for the vibrational states of the target ion with use of the UK Rmatrix code to evaluate electron–ion scattering matrices. The corresponding thermally averaged rate coefficients are computed and fitted to analytical formulas. The obtained DR rate value for CH$_2$NH$_2^+$ is significantly smaller than the values recently employed in the photochemical models of the upper atmosphere of Titan, which has an important impact on the models that aim to reproduce the Titan ammonia abundance. On the other hand, the present results support the astrophysical models reproducing the abundance of the methanimine (CH$_2$NH) detected in massive star formation regions. In these models, the CH$_2$NH$_2^+$ DR is a major route of formation of this molecule with a high prebiotic potential. CH$_2$NH$_2^+$ and NH$_2$CH$_2$O$^+$ are the largest molecular ions for which the DR process was studied theoretically. [Preview Abstract] 

E01.00030: Electron transfer, ionization, and excitation in collisions between protons and the ions Al$^{12+}$ and Si$^{13+}$.} Thomas Winter Coupledstate cross sections are being determined for electron transfer, ionization, and excitation in collisions between keVenergy protons and the hydrogenic ions Al$^{12+}$ and Si$^{13+}$ 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$^{2+}$, ..., C$^{5+}$, and work reported at recent DAMOP meetings on the target ions N$^{6+}$, O$^{7+}$, ..., Mg$^{11+}$. Considering the high asymmetry of the collisional systems, most of the recently chosen bases consist of several hundred Sturmians on the target nucleus and a single $1s$ function on the proton. For excitation and ionization, 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] 

E01.00031: Radiative effects in cold atomion chemistry and the development of a molecular ion qubit Prateek Puri, Michael Mills, Elizabeth West, Christian Schneider, Eric Hudson We present results from a set of experiments investigating cold atomion chemistry in an ion trapMOT hybrid system. With the ability to tune reagent electronic state, identify reaction product masses and branching ratios, and manipulate atomion collision energy from 0.0150 K, the capabilities of our hybrid trapping apparatus are well suited for the study of quantum chemical dynamics. Utilizing these tools, we discuss studies where optical fields are employed to enhance the rate of excited state reactions that are otherwise difficult to probe. We also describe how spontaneous emission dynamics can dramatically suppress chemical reactions in the cold regime, an effect that may be crucial for nextgeneration atomion sympathetic cooling experiments where such reactions may be a limiting mechanism. Lastly, we present our progress on developing a method for reading out the rotational state of a sample of polar molecular ions placed within an ultracold atomic bath, a precursor for developing a highfidelity molecular ion qubit. [Preview Abstract] 

E01.00032: Multichannel Effective Range Theory Analysis of Zeros in the Positronium formation Scattering Amplitude for PositronHydrogen Collisions S. J. Ward, Albandari W. Alrowaily, P. Van Reeth Recently, using the Kohn and inverse Kohn variational methods we found two zeros in the Psformation scattering amplitude for positronhydrogen scattering in the Ore gap and we determined their positions accurately [1]. Two separate circular rings of zeros are present in the corresponding differential cross section due to azithumal symmetry. We are currently analyzing the zeros in the Psformation scattering amplitude using a multichannel effective range theory (MERT) that includes the polarization potential in the second channel [2], which in our case is the Psp channel. This MERT has previously been applied to positronhydrogen collisions [3] for partial waves $L \le 2$ and shown to provide for the Ore gap reasonable results for the partial wave cross sections for Psformation and for Psp scattering. [1] A.~W.~Alrowaily, S.~J.~Ward, P.~Van Reeth, {\it submitted}. [2] S.~Watanabe and C.~H.~Greene, Phys.~Rev.~A {\bf 22}, 158 (1980). [3] S.~J.~Ward and J.~H.~Macek, Phys.~Rev. A {\bf 62}, 052715 (2000). [Preview Abstract] 

E01.00033: Influence of magnetic nonadiabaticity on a solidNemoderated positron beam energy distributions. S. Ghosh, J. R. Danielson, C. M. Surko High quality, trapbased positron beams typically operate in the regime in which particle transport is adiabatic. In this regime, the quantity $(\frac{E_{\perp}}{B})$ is a socalled adiabatic invariant (AI), where $E_{\perp}$ is the energy in cyclotron motion in the direction perpendicular to magnetic field $(B)$. Adiabaticity requires the parameter $\gamma = \frac{2\pi}{\omega_{c}}\frac{v_{}}{B}\frac{dB}{dz}$ to be $ << 1$, where $\omega_{c}$ is the cyclotron frequency and $v_{}$ is the parallel positron velocity. For beam transport energies $\leq 30 eV$, invariance holds quite well for our trapbased beam from the buffer gas trap (BGT) to the testgas cell. However, for larger transport energies, breaking of AI is observed at both ends of the beam tube between solidNe moderator and BGT, due to low $B$ and strong field gradients. This influences the parallel $(E_{})$ and perpendicular energy $(E_{\perp})$ beam distributions, while keeping the total energy conserved. Experimental results for a fixed source magnetic field show increases in perpendicular energy $(E_{\perp})$ with increased moderator bias in the range $5080 V$ (i.e., where $\gamma \agt 1$). Implications of this observation for BGTbased beam systems will be discussed. [Preview Abstract] 

E01.00034: Electroninduced breakdown in gases in RF fields Zoran Petrovic, Marija Puac, Antonije Djordjevic, Dragana Maric, Gordana Malovic Electron avalanches are the necessary first step in transition from an insulating gas to electrical discharge and formation of plasmas. In DC and low frequency fields, a feedback mechanism is needed to support a selfsustained discharge. In RF fields electrons provide the feedback and thus one only needs the contribution of electrons to produce a growing sequence of avalanches that increase the space charge and lead to plasma. Achievement of nonequilibrium atmosphericpressure plasmas, as needed for applications in medicine and agriculture, requires a good knowledge of the RF breakdown in order to produce the nonequilibrium plasma. As the breakdown occurs at zero space charge, one may use swarm techniques such as the Monte Carlo simulation. Using the standard swarm techniques, we have established an explanation of the breakdown curves, scaling, and the basic phenomenology of the RF breakdown through the role of elastic and inelastic collisions in formation of the electron energy distribution function. We have found that ionization and attachment form moving spatially dependent fronts, which reshape the ensemble of electrons and affect the basic physical processes and their spatial profiles. Supported by MESTDRS OI171037 and III41041 and SASA 133 and 155 projects. [Preview Abstract] 

E01.00035: PRECISION MEASUREMENTS 

E01.00036: Propagation of photon in a hot and dense medium Samina Masood We study the vacuum polarization tensor of QED (quantum electrodynamics) at high temperatures and densities to evaluate the coupling constant of QED in such a medium. In this study we can discuss the dispersion of light in a stellar medium showing that certain frequencies can be trapped and the others can propagate through media. [Preview Abstract] 

E01.00037: A femtotesla quantumnoiselimited pulsed gradiometer at Earth's magnetic fields Vito Giovanni Lucivero, Wonjae Lee, Michael Romalis, Mark Limes, Elizabeth Foley, Tom Kornack A major challenge in optical magnetometry is to realize high field sensitivity in Earth's magnetic field. We present a compact atomic gradiometer with a differential magnetic field sensitivity of 14 fT/$\surd $Hz at 50 $\mu $T using a 0.5 cm$^{\mathrm{3}}$ multipass $^{\mathrm{87}}$Rb cell. The gradiometer also has very high common mode rejection ratio greater than 10$^{\mathrm{4}}$ in all three directions. The gradiometer is operated in pulsed mode, with a short pump pulse sequence followed by a free precession interval interrogated by a VCSEL probe laser via paramagnetic Faraday rotation. The noise in the optical rotation measurements is dominated by photon shot noise and atomic spin noise. We derive a generalized Cram\`{e}rRao lower bound (CRLB) for frequency estimation with a nonwhite noise spectrum and find that the experimental sensitivity of the gradiometer is in good agreement with predicted quantum noise sources. This result makes the first DC field gradiometer operating in Earth's field to be experimentally quantumnoiselimited and opens the possibility for further quantum enhancement at the geomagnetic field. [Preview Abstract] 

E01.00038: Toward Directional Detection of Dark Matter in Diamond Mason Marshall, Raisa Trubko, Pauli Kehayias, Matthew Turner, David Phillips, Alex Sushkov, Ronald Walsworth We propose a method to identify weakly interacting massive particle (WIMP) dark matter via induced nuclear recoil in diamond. This 100 nm damage cluster induces stress in the crystal, shifting the energy levels of nearby quantum defects. Crucially, the direction of the track left by the recoil allows us to determine the incoming direction of the particle enabling the possibility of distinguishing between dark matter particles and backgrounds such as solar neutrinos. To measure these damage tracks we will use spectroscopic interrogation of quantum defects such as NV centers in diamond along with other nanoscale imaging techniques. Here we present the proposed technique along with measurements of the preexisting stress variations in diamond. This method could allow for directional detection of WIMPinduced nuclear recoils at solidstate densities, enabling probes of WIMP parameter space below the solar neutrino floor. [Preview Abstract] 

E01.00039: Progress Toward Building a Multiplexed Strontium Optical Lattice Clock Megan Tabbutt, Xin Zheng, Brett Merriman, Kelsey Jacobus, Shimon Kolkowitz Optical lattice clocks are amongst the most accurate and precise devices ever built. Their remarkable stability is now giving rise to a number of novel applications. In contrast to traditional optical lattice clocks, we propose to build a “multiplexed” Strontium optical lattice clock, which will enable high precision differential measurements between two ensembles of ultracold Strontium atoms confined in independently addressable lattices. In this poster, we will present on current progress in building an ultrahigh vacuum chamber capable of reaching $10^{11}$ Torr, building a twostage magnetooptical trap for laser cooling to $\mu$K temperatures, and characterization of our atomic beam source. Updates on a Strontium spectroscopy cell used for laser stabilization will also be shared. In addition, we will discuss plans to use lightassisted collisions to eliminate the collisional linebroadening of the clock transition and to study the photoassociation of $^{87}$Sr in a 1D optical lattice. We also propose new methods for evaluating clock systematics, performing tests of relativity, and achieving quantum enhanced clocks via Rydberg interactions with our multiplexed clock apparatus. [Preview Abstract] 

E01.00040: Millimeterwave precision spectroscopy of dd transitions in potassium Rydberg states Huan Bui, Charles Conover We measure twophoton millimeterwave transitions between nd$_j$ and (n+1)d$_j$ Rydberg states for 30 $\le$ n $\le$ 35 in $^{39}$K to an accuracy of 5$\times$ 10$^{8}$ to determine highn dstate quantum defects and absolute energy levels. $^{39}$K atoms are magnetooptically trapped and cooled to 23 mK, and excited from ground state 4s$_{1/2}$ to nd$_{3/2}$ or nd$_{5/2}$ by frequencystabilized 405 nm and 980 nm externalcavity diode lasers in succession. The magneticfield insensitive nd$_j\rightarrow $ (n+1)d$_j$ $\Delta$m $=0$ transitions are driven by a 16 $\mu$slong pulse of mmwaves before the atoms are selectively ionized for detection. The (n+1)d population is measured as a function of mmwave frequency. Static electric fields in the MOT are nulled in three dimensions to eliminate DC Stark shifts. The twophoton transitions exhibit small but measurable AC Stark shifts in the resonance frequencies. We determine the fieldfree intervals both by extrapolating a sequence of measurements made as a function of mmwave power to zero and directly without extrapolation by applying Ramsey's separated oscillating fields method. Our results give quantum defects for the highn states that are an order of magnitude more accurate than earlier measurements of these quantities. [Preview Abstract] 

E01.00041: Progress on the ARIADNE Axion Experiment Chloe Lohmeyer, Nancy Aggarwal, Jordan Dargert, Melinda Harkness, Harry FosbinderElkins, Andrew Geraci The Axion Resonant InterAction Detection Experiment (ARIADNE) will search for the QCD axion, a hypothetical particle that is a dark matter candidate. Using a new technique based on Nuclear Magnetic Resonance, this new method can probe well into the allowed QCD axion mass range$^{\mathrm{[1]}}$. Sourcing the QCD axion locally in the lab allows for it to be independent of cosmological assumptions. The axion acts as a mediator of novel spindependent forces between a sample of laserpolarized 3He gas and an unpolarized Tungsten source mass. Our project relies on the stability of the rotating segmented source mass and superconducting magnetic shielding. Progress on testing the stability of the rotary assembly will be reported. Magnetic characterization of the mass and shielding will be discussed, along with plans for moving the experiment forward. [1] A. Arvanitaki and A. Geraci, Phys. Rev. Lett. 113, 161801 (2014) [2]~A. Geraci et al., arXiv.1710.05413. Submitted to Proceedings of the 2nd Axion Cavity and Detector Workshop (2017). [Preview Abstract] 

E01.00042: Ultrasensitive Force sensing with optically levitated nanoparticles Chethn Krishna Galla, Evan Weisman, Gambhir Ranjit, Cris Montoya Optically levitated and cooled dielectric particles in high vacuum are a promising tool for use in precision experiments. Since they are decoupled mechanically from the environment optically levitated particles can have very highquality factors enabling ultrasensitive force detection. We describe progress on an experiment using silica nanospheres trapped in an optical lattice to search for deviations from Newton's inverse square law at the micron scale where we have achieved zeptonewton force sensitivity. Recent modifications to the experiment include a fiberbased dipole trap and solid invar cavity. [Preview Abstract] 

E01.00043: ABSTRACT WITHDRAWN 

E01.00044: ABSTRACT WITHDRAWN 

E01.00045: Sympathetic cooling of levitated nanospheres using cold atoms Eduardo Alejandro, William Eom, Daniel Grass, Apryl Witherspoon, Cris Montoya, Gambhir Ranjit, Andrew Geraci The intermediate mesoscopic regime between classical and quantum mechanics can be explored in search of new physics using groundstate cooled silica nanospheres. In our twochambertrapping system, a MOT and optical tweezer prepare atoms and a nanosphere respectively for sympathetic cooling. The atoms couple to the sphere through radiation pressure forces mediated by a 1D optical lattice. The molasses cooling of the atoms can sympathetically reduce the centerofmass motion of the trapped sphere. Such cooled spheres can be used for precision sensing, matterwave interferometry, and could enable new hybrid quantum systems where mechanical oscillators act as transducers. [Preview Abstract] 

E01.00046: Portable Yb Optical Lattice Clock: Towards Precision Measurement Outside the Lab Wesley Brand, Robert Fasano, Richard Fox, William McGrew, Youssef Hassan, Xiaogang Zhang, Kyle Beloy, Daniele Nicolodi, Andrew Ludlow As optical atomic clocks continue to increase in precision, interest has grown in redefining the SI second based on an optical atomic transition. Before the second can be redefined, a wide range of optical clock comparisons must be made to rigorously test the realizable performance. Due to challenges in longdistance optical time and frequency transfer, these comparisons often require physically moving one optical clock near another. However, constructing a robust portable system is challenging for this complex experimental apparatus. Here, we report on experiments and design efforts for developing portable Yb optical lattice clocks with systematic uncertainty $<10^{17}$ employing automatic systems for optical alignment and locking, despite a compact package of ~$1.5$ m$^3$. Additionally, we provide a brief update on recent developments and improvements on laboratorybased Yb optical lattice clocks at NIST. [Preview Abstract] 

E01.00047: Does warming a magnetic shield change its properties? Benedict Feinberg, Harvey Gould We have previously reported (AIP Advances \textbf{8}, 035303 [2018]) that delayed changes in magnetization cause the magnetic flux density inside a Permalloy (mumetal) shielded volume to decrease over hours and days. To test if this effect changes with temperature, we are performing similar measurements on a warmed shield. In a magnetically nulled region, the shield, wrapped with heating tapes and insulation, is heated to about 45 $^{\circ}$C. The heaters are then turned off, and the shield demagnetized by passing a 60 Hz current through a toroidal winding. After a short wait, an external magnetic field is applied and the magnetic flux density in the center of the shielded volume is monitored over the next few hours. Preliminary results will be presented. [Preview Abstract] 

E01.00048: Properties of alkali atoms in solid parahydrogen Ugne Dargyte, Sunil Upadhyay, Jonathan Weinstein Alkali atoms trapped in solid parahydrogen exhibit excellent spin coherence properties at high electron spin densities. We have studied potassium, rubidium, and cesium atoms implanted in parahydrogen. Different species exhibit orderofmagnitude differences in optical pumping and readout. Similarly, different alkali atoms have dramatically varying ensemble transverse relaxation times. These properties and other measurements in parahydrogen will be presented. [Preview Abstract] 

E01.00049: Multiaxis Compact Gyroscope with a Gratingchip and Point Source Atom Interferometry Xiaojie Li, Qi Fu, Zhixin Meng, Peiqiang Yan, Yanying Feng Developing a compact atom interferometer (AI) with the ability of multiaxis measurement is important for extending its applied scope to field environment. We propose a new design of multiaxis AI gyroscope based on a grating chip, which allows a single input laser beam for atomic trapping and coherent manipulation. Multiple AIs are formed by the input laser beam along with the other four diffractive beams generated by the grating chip. The rotation induced phase shifts from different input axes lead to different spatial interference fringes due to the modulation of the atomic velocity. With the point source interferometry (PSI) and the spatially resolved detection, multiaxis rotations may be measured by imaging the final atom cloud after the interferometer sequence and decoding the information of spatial fringes from different input axes. We use MonteCarlo based method to simulate the grating AI signals under multiaxis rotation input and evaluate its application as a multiaxis gyroscope. The effects of image plane position, initial temperature of the atom cloud and rotation rate on fringe periods are analyzed and the scale factor fitting the phase gradient and rotation rate is estimated. Initial experimental results are also reported. [Preview Abstract] 

E01.00050: Design and characterization of a ring cavity with a flattop profile Yaneth Torres, Alejandra Lopez, Marisol Billion, Wanderson Pimenta, John Franco, Eduardo Gomez Optical cavities are used to improve the atom interferometry techniques, providing spatial filtering of the interferometry beam and the use of relatively low input beam power due to the resonant enhancement of the intracavity power. In the present work, we report the design and characterization of a bowtie cavity of highqualityfactor composed oftwo curves and two planar mirrors. The geometry of the cavity is chosen to be able to interact with a cloud of trapped atoms with a beam as homogeneous as possible. We lock the laser to the cavity to have a stable field using the PoundDreverHall technique. We experimentally demonstrate the generation of a flattop light profile inside the cavity by the superposition of the LG00and 01modes. The ring cavity is not confocal; thus the transverse modes are not degenerate. We inject two independent transverse modes to the cavity that are separated by 200 MHz in frequency. The total intensity given by the interference of the two modes can be well understood in terms of the addition of the intensities of individual fields since the difference in frequency of the fields is larger than the Rabi frequency of any relevant atomic transition. [Preview Abstract] 

E01.00051: Fieldoperation of an atomic gravimeter for geodesy and metrology Xuejian Wu, Zachary Pagel, Bola Malek, Holger Müller Gravimeters are important in geodesy and metrology for gravity surveys, mineral exploration, natural disaster monitoring, and gravity determination for realizing the kilogram with the Watt balance. Compared to gravimeters based on springs, superconducting coils, microelectromechanical system devices, or falling cubes, atomic gravimeters are based on lightpulse atom interferometry. Since laser wavelength defines the photon momentum with high precision and no mechanical movement is involved with the measurement, atomic gravimeters can be more accurate and have better longterm stability. However, stateofart atomic gravimeters are complicated and their application is usually restricted to wellcontrolled laboratories. Here, we report fieldoperation of an atomic gravimeter based on a simple laser system and a novel pyramidal magnetooptical trap. In the laboratory, we have measured the tidal gravity variation with a sensitivity of 370 nm/s$^{\mathrm{2}}$/$\surd $Hz. The results show that the ocean tide loading is proportional to the water level in the San Francisco Bay. In the field operation, we have measured the absolute gravity on Berkeley hills. The atomic gravimeter has been transported in a trail of \textasciitilde 4.7 km and measured absolute gravity with a variation of about 1 mm/s$^{\mathrm{2}}$. Fielddeployable atomic gravimeters will bring precise absolute gravity measurements to geodesy and metrology. [Preview Abstract] 

E01.00052: ABSTRACT WITHDRAWN 

E01.00053: Progress towards spectroscopy of forbidden vibrational overtones in O$_2^+$ Annika Lunstad, Julia Pfatteicher, David Hanneke The rich internal degrees of freedom of molecules provide opportunities such as tests of basic physics, precision timekeeping, and searches for new physics. For example, the vibrational overtones of O$_2^+$ have intrinsically narrow linewidths and are naturally immune to many systematic effects. They could form the basis for optical clocks or probes of variation of fundamental constants. The transitions are electricdipole forbidden, but can be driven with two photons. We report on progress towards measuring overtone frequencies and reducing their uncertainties from the current level of many gigahertz. Our efforts include state production by photoionizing from a cold, pulsed beam of neutral molecules as well as state detection by photodissociation and timeofflight mass spectrometry. [Preview Abstract] 

E01.00054: Technical Progress Towards Measurement of the Anapole Moment of $^{\mathrm{137}}$Ba$^{\mathrm{19}}$F Sidney Cahn, Maximilian Beyer, JaiMin Choi, David DeMille Nuclear spindependent parity violation (NSDPV) effects are due to several interactions, including the nuclear anapole moment, a parityviolating electromagnetic moment confined to the interior of the nucleus. The supersonic beam source generated the proofofprinciple results for the $^{\mathrm{138}}$Ba$^{\mathrm{19}}$F control molecule for the naturally abundant but spin0 $^{\mathrm{138}}$Ba nucleus. We have improved the apparatus by incorporating a pulsetube refrigerator to produce a bright buffergas source of $^{\mathrm{137}}$Ba$^{\mathrm{19}}$F molecules at cryogenic temperatures, building an MTSlocked (modulation transfer spectroscopy) laser and PDH (PoundDreverHall)locked cavity for laser locking to address the largest systematic found in earlier work, and performing the laser spectroscopy of $^{\mathrm{137}}$Ba$^{\mathrm{19}}$F. [Preview Abstract] 

E01.00055: ULTRAFAST AND STRONG FIELD PHYSICS 

E01.00056: Lowenergy photoelectron interference structure in attosecond streaking Jintai Liang, Yueming Zhou, Peixiang Lu By numerically solving the timedependent Schrödinger equation, we theoretically investigate the interference structures of lowenergy photoelectron spectrum produced by a single attosecond pulse in the presence of an infrared laser field. These lowenergy photoelectrons ionized by the attosecond pulses could be driven back to the parent ion by the infrared laser field and thus the photoelectrons momentum distributions exhibit complicated interference structures. We show that these structures respectively originate from the interferences between the direct electrons (the electron reaching the detector without interaction with the parent ion after ionization) and direct, direct and nearforward rescattering, direct and backward rescattering, backward and backward rescattering electrons. Moreover, by changing the time delay between the attosecond pulse and the infrared laser field or the center frequency of the attosecond pulses, these interference structures could be selectively enhanced or suppressed. The information of the electronic dynamic process and the continuum electronic wave packets is encoded in the interference structures. As an example, we show that the phase of the electronic wave packets ionized by the linear and circular polarized attosecond pulse can be extracted by the forwardrescattering holography. [Preview Abstract] 

E01.00057: Ab initio theory for extracting the carrierenvelope phase from stereo ATI measurements Dustin Ursrey, Brett Esry Using stereo above threshold ionization measurements of xenon to extract the carrierenvelope phase (CEP) of a single laser pulse via parametric amplitude plots (PAPs) has had great success [1], but the associated analysis is largely based on empirical observations. Here, we present a general, exact, ab initio theory that gives analytic expressions for the spatial asymmetry and thus the PAP. Our formulation shows that the experimental observation that the asymmetry varies approximately sinusoidally in the CEP is a lowestorder approximation valid mainly at low intensities. With our exact result, we will examine the impact of the higherorder contributions, especially their effect on the extraction of the CEP. In addition, our analytic result potentially enables the absolute CEP to be extracted without the need for carefully chosen energy ranges or solving the TDSE as are currently required. We will also discuss how our results can be used to identify experimental issues in the PAPs and generally how they can improve the CEP extraction process. [1] T Rathje et al 2012 J. Phys. B: At. Mol. Opt. Phys.45 074003 [Preview Abstract] 

E01.00058: A Comparison of Numerical Approaches to the Solution of the TimeDependent Schroedinger Equation in One Dimension Heman Gharibnejad, Barry Schneider, Mark Leadingham, Henry Schmale We present a simple, onedimensional model of an atom exposed to a timedependent intense, shortpulse EM field with the objective of teaching undergraduates how to apply various numerical methods to study the behavior of this system as it evolves in time using several time propagation schemes. In this model, the exact coulomb potential is replaced by a softcore interaction to avoid the singularity at the origin. While the model has some drawbacks, it has been shown to be a reasonable representation of what occurs in the fully threedimensional hydrogen atom. A variety of approaches such as CrankNicholson, splitoperator, Lanczos and Chebyshev are compared both for accuracy and efficiency. The model can be used as a tool to train undergraduate physics majors in the art of computation and software development. [Preview Abstract] 

E01.00059: Strongfield photoemission from metal nanospheres. Erfan Saydanzad, Jianxiong Li, Uwe Thumm We simulated velocitymapimage (VMI) photoelectron spectra for strongfieldionization of metal nanospheres by extending our classical trajectory sampling model for streaked photoemission [1]. Our numerical model accounts for (i) photoelectron emission on the surface of the nanoparticle by an intense IR laser pulse and (ii) photoelectron propagation outside the nanosphere in the presence of incident and induced plasmonic fields. From the simulated photoelectronfinalvelocity distribution we derive VMI spectra for gold nanospheres with diameters between 10 and 100 nm. In analyzing our numerical results, we study the effects of electronelectron and electronhole interactions and of rescattered photoelectrons on VMI spectra. [1] E. Saydanzad, J. Li, and U. Thumm, Phys. Rev. A 95, 053406 (2017). [Preview Abstract] 

E01.00060: The Ultimate Energy Limit of HHG and Strong Field Rescattering Barry Walker, Michael Klaiber, Karen Hatsagortsyan, Jian Wu, Sui Luo, Patrick Grugan Recollision for a laser driven atomic system is investigated in the nonrelativistic to relativistic regime via a strong field quantum description and Monte Carlo semiclassical approach. We find the relativistic recollision energy cutoff is independent of the ponderomotive potential $U_p$, in contrast to the wellknown 3.2~$U_p$ scaling. The relativistic recollision energy cutoff is determined by the ionization potential of the atomic system and achievable with nonnegligible recollision flux before entering a ``rescattering free'' interaction. The ultimate energy cutoff is limited by the available intensities of short wavelength lasers and cannot exceed a few thousand Hartree. This end to rescattering physics, which begins at 1,000 Hartree (27,000 eV,) sets the energy boundary for HHG and recollision based attosecond physics. [Preview Abstract] 

E01.00061: Modeling carrierenvelope phase effects on frustrated tunnel ionization B.A. deHarak, J.P. Ziegel, V.C. ViteriPflucker, R.D. Glover, D. Chetty, A.J. Palmer, I.V. Litvinyuk, R.T. Sang The fact that an electron can tunnel out of the potential well of its parent atom or molecule in the presence of a strong laser field is the basis of a number of strongfield phenomena such as above threshold ionization, and nonsequential multiple ionization. In both of those cases the parent is left in an ionized state. However, there is a chance that after the electron has tunneled it will return to a bound state  a process known as frustrated tunnel ionization (FTI)~[Nubbemeyer, T., et al. Phys. Rev. Lett. 101(23): 233001 (2008)]. Here we present calculations of fewcycle laser pulse FTI yield for argon as a function of carrierenvelope phase using the rescattering model~[P.B. Corkum, Phys. Rev. Lett. 71, 1994 (1993)] with the addition of a coulomb potential term when dealing with the ``free'' electron. We will contrast the use of different coulomb potentials and compare these calculations to some of our recently obtained experimental results. [Preview Abstract] 

E01.00062: Frustrated tunnel ionization of argon by intense fewcycle infrared laser radiation. Thomas Pauly, Noah Smith, Klaus Bartschat, Nicolas Douguet We report calculations for strongfield ionization and excitation of argon by directly solving the timedependent Schr\"o dinger equation in a singleactive electron model. In particular, we are interested in the process of ``frustrated tunnel ionization'', where a fieldionized electron is driven back towards the nucleus by the changing laser field and ultimately gets recaptured into an excited bound state without the possibility of escaping again due to the fact that the fewcycle pulse has already weakened too much. This process is currently being investigated experimentally at Griffith University [1] and also theoretically, using a semiclassical model, at Illinois Wesleyan University [2]. We discuss the effect of different potentials and carrierenvelope phases, as well as the laser intensity and the ellipticity of the radiation, on the theoretical predictions. Where possible, we compare our results with experimental data and other theoretical results. [1] R.T. Sang (2019), private communication. [2] B.A. deHarak (2019), private communication. [Preview Abstract] 

E01.00063: Progress towards subfemtosecond pulse generation using molecular modulation David Gold, Deniz Yavuz We have constructed a broadband continuouswave optical modulator at a frequency of 90 THz. Our modulator consists of a deuteriumgas filled cavity that is resonant at both the pump and Stokes wavelengths. With our setup, we can modulate almost any beam in the optical region of the spectrum with a single pass efficiency of $\approx $ 10$^{\mathrm{4}}$. This is a comparable efficiency to the fastest electrooptic modulators, but with a modulation frequency 1000 times greater. We have used this system to modulate a Ti:sapph laser and produce up and down shifted sidebands. The Ti:sapph laser produces a pulse train with pulse widths of 50 fs and a repetition rate of 94 MHz. The Ti:sapph output is modematched to the cavity and is modulated in a single pass. The cavity output is separated from the intense pump and Stokes beams using a dichroic mirror and is sent into a custombuilt grating spectrometer to demonstrate the presence of the antiStokes sideband with spectral features matching the initial Ti:sapph beam. Additionally, we show that the sideband is pulsed with a repetition rate of 94 MHz just like the initial beam. In the future, with dispersion compensation, applying this technique to a state of the art Ti:sapph could yield the shortest pulses ever produced in the optical region of the spectrum. [Preview Abstract] 

E01.00064: Highorder harmonic generation driven by twocolor 800400 and 800266 nm laser fields T. Severt, J. Tro\ss, G. Kolliopoulos, P. Timilsina, C. TralleroHerrero$^*$, I. BenItzhak We study the generation of highorder harmonics in argon driven by twocolor laser fields. In particular, we compare the flux of each harmonicorder driven by singlecolor 800 nm, 400 nm, and 266 nm fields as well as twocolor 800400 nm, and 800266 nm fields. For commonly generated photon energies, the twocolor laser fields outperform the single color 800 nm driver in the 1435 eV spectral region, enhancing the flux by 225 times, depending on the harmonic order. On the other hand, the single color 400 nm and 266 nm laserfields produced comparable fluxes to their twocolor counterparts. Additionally, we determined that the divergence of the 800266 nm field is 23 times less than all the other driving fields, leading to a higher photon flux along the propagation axis. We also briefly highlight the phase dependence of the highorder harmonics generated by the twocolor fields and explore phase shifts between the harmonics and total ionization rate. \newline \newline \textsuperscript{*} Current address Physics Department, University of Connecticut, Storrs, CT 06269, USA. [Preview Abstract] 

E01.00065: The dependence on initial configuration of strong fielddriven isomerization of neutral and ionic C$_2$H$_2$ targets Bethany Jochim, Ben Berry, T. Severt, Peyman Feizollah, M. Zohrabi, Kanaka Raju P., K. D. Carnes, I. BenItzhak, E. Wells As a test bed for hydrogen migration, the conversion between the C$_2$H$_2$ molecule's acetylene (HCCH) and vinylidene (H$_2$CC) isomers has been a subject of great interest. We further explore isomerization of this system, examining the ultrafast laserinduced dynamics of C$_2$H$_2^q$ ion beam targets. These ion beams are generated with various initial configurations, including HCCH, H$_2$CC, and \emph{cis}/\emph{trans}. We show that the branching ratio between acetylenelike (CH$^{q_1}$ + CH$^{q_2}$) and vinylidenelike (C$^{q_1}$ + CH$_2^{q_2}$) fragmentation$^{\dag}$, measured using a coincidence 3D momentum imaging technique, exhibits a strong dependence on the target's initial configuration. Specifically, while an HCCH target, such as a C$_2$H$_2^+$ beam produced from C$_2$H$_2$, undergoes acetylenelike and vinylidenelike breakup at comparable levels, for H$_2$CC targets, there is a distinct preference for the latter. For example, acetylene breakup is negligible for C$_2$H$_2^$. \\ \\ $^{\dag}$Includes CH + CH and C + CH$_2$ [Preview Abstract] 

E01.00066: Dynamic Alignment in Enhanced Ionization of Water Greg McCracken, Chelsea LiekhusSchmaltz, Phil Bucksbaum The enhanced ionization of water is studied in NIR, ultrafast pulses. "Enhanced ionization" leads to symmetric three body decay from multiple charge states of H$_2$O. Linearization of the molecule in the strong field is shown to cause dynamic alignment of the HH bond to the polarization. This a main feature of the enhanced ionization channels. The process by which the molecule unbends is studied extensively by identifying pathways for multiple ionization in the dication states. This is achieved by comparison of channels for different isotopes across a range of intensities. Ionization of inner valence electrons plays a key role. Additionally, it is shown that multiple ionization does not only occur in the enhanced ionization regime, even for longer pulses. Double, sequential tunneling ionization of the lone pair orbital is also observed. Here, alignment to the HH bond does not occur, and distortion of the molecular frame prior to ionization is minimal. The onset of this channel is at significantly higher intensity than that observed for triple and quadruple ionization channels. [Preview Abstract] 

E01.00067: Resonant finalstate effects in timeresolved photoemission time delays from Cu(111) surfaces. Marcelo J. Ambrosio, Uwe Thumm Photoemission from solid targets includes the excitation and propagation of electrons inside the substrate, followed by their propagation in vacuum and detection [1,2]. While the imprint of the initialstate valence electronic structure of solids on photoemission spectra is well understood from photoemission spectroscopy in the energy domain, stateoftheart timeresolved photoelectron spectroscopy [3,4] allows, in addition, the scrutiny of photoelectron propagation in the electronic continuum. We calculated photoemission spectra as a function of the delay between the exciting attosecond pulse train and assisting infrared (IR) laser pulse. Accounting for finalstate interactions of the photoelectron with the IR electric field and the periodic substrate, our simulations show a resonantly enhanced sideband yield at photoelectron kinetic energies near 23.9 eV, in conjunction with a pronounced increase of the photoelectron wavefunction amplitude inside the solid on a length scale of a few nanometers. This resonant shift of finalstate photoelectron probability density towards the bulk can be interpreted as an increase in the photoelectron propagation time in the solid and is commensurate with the resonant phases recently measured by Kasmi et al. [3]. [1] R. Locher et al., 2015 Optica 2, 405. [2] M. J. Ambrosio et al., 2018 Phys. Rev. A 97, 043431. [3] L. Kasmi et al., 2017 Optica 4, 1492. [4] Z. Tao et al., 2016 Science 353, 62. [Preview Abstract] 

E01.00068: Wigner time delay in photodetachment Soumyajit Saha, Gopalan Aravind, Jobin Jose, Pranawa Deshmukh, Valeriy Dolmatov, Anatoli Kheifets, Steven Manson Using Cl$^{\mathrm{\thinspace }}$as a test case, Wigner time delay [1] in the photodetachment process has been investigated theoretically for the outer 3$p$ subshell using the relativisticrandomphase approximation (RRPA). Time delay was probed from threshold to 80 eV to investigate threshold effects, including the shape resonance, along with the Cooper minimum region. This study of the threshold effects is possible for negative ions because the phase of the photodetachment process is not dominated by the Coulomb phase as it is in photoionization. The isoelectronic Ar atom was also studied for comparison and the results show significant differences, both qualitative and quantitative, between the time delays for Cl$^{\mathrm{}}$ and Ar photoemission at low photoelectron energy, but they are rather similar in the Cooper minimum region, where the Coulomb phase is small. In particular, the Wigner time delay in Cl$^{\mathrm{}}$ exhibits dramatic energy dependence just above threshold, and a rapidly increasing time delay in the vicinity of the shape resonance. A strong angular dependence of time delay has also been found near the threshold region for Cl$^{\mathrm{}}$ case, and absent in case of photoionization of Ar. The origin of these phenomenologies is explained and a prospectus for future work is presented. Work partially supported by SERB (India) and the US DOE. [1] E. P. Wigner, Phys. Rev. \textbf{98}, 145 (1955). [Preview Abstract] 

E01.00069: Role of shakeup channels in Neon photoionization time delay Didarul Alam, Nicolas Douguet, Stefan Donsa, Luca Argenti The longstanding controversy surrounding the time delay difference ($21\pm5$~as at 105~eV) measured in the photoionization of neon from the $2s$ and $2p$ shells [1] has been explained in a recent experimental work [2]. As predicted by a past {\it ab initio} study [3], it was shown in [2] that shakeup channels, which were not resolved in [1], were responsible for the discrepancy between theoretical calculations and the experimental data. This new finding, however, rises the question whether the shakeup channel indicated as being responsible for the measurement bias is the dominant one or if other channels might contribute significantly. In this work, we employ the \footnotesize\textsc{NEWSTOCK} {\it ab initio} method to analyze and quantify the effect of shakeup channels above 80~eV photon energy in neon. We also perform realistic XUVpumpIRprobe timedependent calculations and compare our results with the experimental data [2]. [1] M. Sch\"{u}ltze {\it et al.} Science {\bf 328} 1658 (2010), [2] M. Isinger {\it et al.} Science {\bf 358} 893 (2017), [3] Feist {\it et al.} PRA {\bf 89} 033417 (2014). [Preview Abstract] 

E01.00070: Resonant Anisotropic Emission in TwoPhoton Interferometric Spectroscopy Nicolas Douguet, Bejan Ghomashi, Luca Argenti A variant of RABBITT spectroscopy, in which the attosecondpulse train comprises just two consecutive harmonics of the fundamental infrared probe frequency, is explored to measure timeresolved photoelectron emission in systems that exhibit autoionizing states [1]. In this scheme, onephoton and twophoton amplitudes interfere giving rise to asymmetric photoemission. 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 using a onedimensional model with a symmetric zerorange potential that supports bound states and shaperesonances. The asymmetric photoelectron emission near a resonance is computed using perturbation theory and by solving the timedependent Schoedinger equation. [1] Bejan Ghomashi, Nicolas Douguet, and Luca Argenti arXiv:1811.10160 (2019) [Preview Abstract] 

E01.00071: Internucleardistance and angle dependence of strongfield ionization rates of UVdissociated halomethanes. F. Ziaee, K. Borne, Kanka Raju P., R. Forbes, B. Kaderiya, Y. Malakar, T. Severt, I. BenItzhak, A. Rudenko, D. Rolles The dependence of the strongfield ionization rates of iodinecontaining halomethanes on the iodinecarbon internucleardistance and the orientation of molecular bonds with respect to the polarization direction of an infrared laser field is investigated utilizing a UV pumpNIR probe technique. Excitation at 258 nm initiates a resonant singlephoton absorption cleaving the carboniodine bond. A subsequent NIR laser pulse ionizes the dissociating molecule at different delays. Measuring single and double ionization rates as a function of pumpprobe delay allows the determination of their internucleardistance dependence. Furthermore, by determining the delaydependence of the fragment ion angular distributions, the gradual transition of the ionization from the molecular to the atomic limit is probed. \textit{Supported by the U.S. Department of Energy under grant no.~DEFG0286ER13491}. [Preview Abstract] 

E01.00072: Laserkick induced helium dimer dynamicsa twobody interferometer Qingze Guan, Doerte Blume, Maksim Kunitski, Holger Maschkiwitz, J\"org Hahnenbruch, Sebastian Eckart, Stefan Zeller, Anton Kalinin, Markus Sch\"offler, Lothar Ph. H. Schmidt, Till Jahnke, Reinhard D\"orner The $^4$Hedimer, one of the most weakly bound molecules in nature, gets gently kicked by a short intense laser pulse. This laserkick, which is most prominently felt at small internuclear separations, induces both rotation and dissociation of the helium dimer. Due to the interplay between the bound and the dissociative portions of the wave packet, dynamical interference patterns in the alignment signal are observed experimentally. Our parameterfree theory results are in excellent agreement with the experimental results. The dynamics, which sensitively depends on the length of the laser pulse, is proposed to be used to probe the tunability of the heliumhelium interaction by an external electric field. Our results are expected to guide the next generation of experiments [Preview Abstract] 

E01.00073: Photoionphotoelectron coincidence measurement on dissociative ionization of CO2 driven by XUV pump and NIR probe pulses. S. J. Robatjazi, S. Pathak, W. L. Pearson, J. Powell, Kanaka Raju P., J. Buerger, D. Rolles, A. Rudenko We present the results of an extremeultraviolet (XUV) pump nearinfrared (NIR) probe experiment on dissociative ionization of a CO2 molecule. The molecules are ionized by a train of high harmonics (11th to 19th ) of the NIR laser beam at 790 nm, and the ensuing dynamics are probed by the timedelayed NIR pulse. A doublesided velocity map imaging spectrometer equipped with two delayline detectors is employed to detect photoions and photoelectrons in coincidence. Coincident measurement of the photoelectron energies allows us to separate contributions from higherorder harmonics, and to focus on the dynamics driven only by the 11th and 13th harmonics. We show the yields of CO2$+$ parent ions as well as CO$+$ and O$+$ fragments resulting from the XUVNIR dissociative ionization as a function of XUVNIR delay, and analyze coincident electron spectra for each channel. Filtering on photoelectron energies allows us to disentangle contributions from different excited cationic states, and enables deeper understanding of ultrafast dynamics observed in earlier, noncoincident measurement on CO2 dissociative ionization by XUVNIR pumpprobe pulses [1]. [1] H. Timmers et al, Phys. Rev. Lett. 113, 113003 (2014). [Preview Abstract] 

E01.00074: Examination and control of H$_3^+$ formation in ethane with intense laser pulses Charles J. Schwartz, Naoki Iwamoto, S. Zhao, J.L. Napierala, S.N. Tegegn, A. Solomon, E. Wells, Bethany Jochim, Kanaka Raju P., T. Severt, Peyman Feizollah, K.D. Carnes, I. BenItzhak Guided by COLTRIMS identification of H$_3^+$ fragmentation channels, an adaptive learning algorithm supplied with 3D momentum based feedback is used to identify intense laser pulse shapes that control H$_3^+$ formation from ethane. Since a C$_2$D$_4^{2+}$D$_2$ intermediate state is thought to lead to D$_3^+$ formation via roaming of the D$_2$, we use the D$_3^+$:C$_2$D$_4^{2+}$ ratio as the control objective. In a similar measurement, we control the ratio of D$_2$H$^+$ to D$_3^+$ produced from the D$_3$CCH$_3$ isotopologue of ethane, which selects between trihydrogen cations formed from atoms on one or both sides of ethane. Both the D$_3^+$:C$_2$D$_4^{2+}$ and D$_2$H$^+$:D$_3^+$ ratios can be modified by a factor of two or more. In addition, 2D scans of linear chirp vs. thirdorder dispersion are conducted for a few fourthorder dispersion values while the D$_2$H$^+$ and D$_3^+$ production are monitored. These dispersion scans are not as successful at modifying the D$_2$H$^+$:D$_3^+$ ratio as the adaptive search. [Preview Abstract] 

E01.00075: Resonant propagation of strong xray fields Kai Li, Phay Ho, Linda Young Modification of strong xray fields propagating through a resonant medium of neongas is studied. The simulation is based on solution of a onedimensional MaxwellBloch equation, with the incident xray photon energy near resonance with 1s3p transition. We solved for the evolution of the total fields, pump, simulated emission and absorption, as a function of input pulse properties. The pulse compression and spectral modulation revealed in the simulation is potentially applicable to control xray freeelectron laser (XFEL) pulse properties in experiments. The nonlinear propagation of strong XFEL pulses is also of interest for xray optics and spectroscopy. [Preview Abstract] 

E01.00076: Extended Fluorescence Emission Time from Clusters in Intense Xray Freeelectron Laser Pulses Phay Ho, Chris Knight, Linda Young Motivated by the recent work by Classen and coworkers [Phys. Rev. Lett. 119, 053401 (2017)] of exploiting the Hanbury Brown and Twiss effect for molecular imaging with xray fluorescence, we theoretically examined the fluorescence spectrum of a nanocluster from XFEL pulses with our MC/MD method. Using Ar clusters as a prototype, we focused on fluorescence processes in intense xray fields and found that nonlinear xray absorption leads to a highdegree of ionization and creates a dense electron environment within the sample on the femtosecond timescale. These ultrafast processes produce xray emission profiles in an extended sample that are very different from the atomic profile. In addition to the direct photoionization pathways, electronion recombination processes provide additional pathways in clusters to reach the same fluorescence channels and give rise to higher yields in K$_{\mathrm{\alpha }}$ and its hypersatellite from doublecorehole state (K$_{\mathrm{\alpha }}^{\mathrm{H}})$. The presence of the recombination pathway leads to extended fluorescence emission time beyond the lifetime of the coreexcited states. We show that the K$_{\mathrm{\alpha }}^{\mathrm{H}}$ emission line can be a good candidate for fluorescence imaging as it has relatively short emission time compared to the xray induced distortion time. [Preview Abstract] 

E01.00077: Laser control of transmission electron microscope electron wave function Carter Turnbaugh, Osip Schwartz, Jeremy Axelrod, Sara Campbell, Robert Glaeser, Holger Müller We demonstrate continuous laser control of the spatial phase of an electron wave function in a transmission electron microscope (TEM). Using a nearconcentric FabryPerot cavity, we produce record continuouswave laser intensities ($\sim 43 \mathrm{GW} / \mathrm{cm}^2$) required to manipulate electron wave functions via the ponderomotive potential. We acquire a TEM image of the freespace light wave, showing the effect of the light wave on the electron beam. The periodic structure of the standing light wave also acts as an electron diffraction grating, and we recorded images showing the electron diffraction. Finally, in the back focal plane of the TEM, we aligned the unscattered electron beam of the TEM with a standing light wave antinode in order to phase shift the unscattered beam relative to the scattered beam. These results can be applied to create a Zernike phase plate for TEMs. In electron microscopy of cryogenically frozen biomolecules, specimens produce very little amplitude contrast and only weak phase contrast. Although techniques exist to use the TEM optics to produce some contrast, they provide little low frequency information, which limits the ability to perform atomic resolution 3D reconstructions of smaller proteins. [Preview Abstract] 

E01.00078: QUANTUM INFORMATION AND QUANTUM OPTICS 

E01.00079: Disordered dimer chains in waveguide quantum electrodynamics Imran Mirza, John Schotland Cold atoms trapped near optical fibers provide an excellent experimental setup to study singlephoton propagation in periodic and disordered dimer chains (pair of atoms coupled through dipoledipole interaction). The confinement of light in subwavelength fibers creates optical spinorbit coupling which opens up the possibility of chiral photon emissions (preferential emission directions) into the waveguide [\textit{``Chiral quantum optics'', }Nature 541, 473480 (2017)]. By considering two types of position disorders, namely the disorder in the dimer length and dimer separation, we study how dipoledipole interaction along with the chiral photon emissions impacts the transport of photons [\textit{``Dimer chains in waveguide quantum electrodynamics}'' arXiv: 1808.10048]. This study has relevance to the area of quantum communication and to the photonic analog of manybody1D disordered models of condensed matter physics. /abstract [Preview Abstract] 

E01.00080: Progress towards building a dual species programmable trapped ion quantum simulator ChungYou Shih, Sainath Motlakunta, Nikhil Kotibhaskar, Manas Sajjan, YiHong Teoh, Fereshteh Rajabi, Roland Hablutzel, Rajibul Islam Long coherence times, high fidelity qubit state initialization and detection, and programmable longrange interactions make trapped ions a leading platform for quantum simulation. Here, we report on our progress towards developing a scalable dual species Yb+/Ba+ quantum simulator. Our apparatus includes a novel optical addressing system, based on Fourier holography, that is immune to imaging imperfections. Such a programmable optical addressing system can be used to engineer programmable qubit interaction graphs, that enable the simulation of higher dimensional spin systems with a linear ion chain. Tools from classical optimization methods, such as machine learning techniques, will be used to efficiently program the quantum simulator to solve a range of problems, in areas such as quantum manybody physics, high energy physics, and quantum chemistry. [Preview Abstract] 

E01.00081: ABSTRACT WITHDRAWN 

E01.00082: Coherent Control of Thermal Atoms with Photonic Crystal Cavities Hadiseh Alaeian, Ralf Ritter, Artur Skljarow, Harald Kubler, Tilman Pfau, Robert Low Unless proper modifications are employed, the atomphoton interaction is an inefficient process in free space. Historically, optical and superconducting cavities have been used successfully to increase the atomphoton interaction probability for the optical and microwave photons, respectively. With recent advancements in nanofabrication, integrated Nanophotonic devices have been employed successfully to enhance the quantum optical phenomena in several solidstate based platforms like quantum dots and vacancy centers. In this work, we present our recent theoretical and experimental efforts on the integration of highQ cavities with thermal atoms beyond the perturbative limit. In particular, we discuss about an optimized cavity in a Si$_{\mathrm{3}}$N$_{\mathrm{4}}$ photonic crystal supporting a highQ mode with small volume at 780nm, i.e. 5S $\to $ 5P of rubidium. Through detailed MonteCarlo calculations and incorporating all the device effects, including the Purcell enhancement and CasimirPolder potential, we demonstrate the feasibility of reaching a strong atomlight coupling down to a single photon. [Preview Abstract] 

E01.00083: Progress towards number squeezing a weak coherence state using a Kerr nonlinearity based on Rydberg EIT Daniela Angulo Murcillo, Josiah Sinclair, Kyle Thompson, Aephraim Steinberg Recent realization of a large, onresonant crossKerr nonlinearity based on Rydberg atoms and electromagnetically induced transparency (EIT) provides a new platform for longsought after applications of singlephoton nonlinearities like photonnumber squeezing, and quantum nondemolition (QND) measurement of photon number. We report on progress towards measurementinduced number squeezing for a weak coherent state. The experiment will involve two optical pulses, the probe and signal, which interact via a Rydbergbased Kerr medium. During the interaction, the probe acquires a phase shift proportional to the number of photons in the signal. After the interaction, the phase shift of the probe is measured. This act of observation on the probe is expected to reduce the variance in photon number on the signal, producing a weakly numbersqueezed coherent state. To characterize this squeezing, we are in the process of upgrading our experimental setup to displace the signal state near the vacuum and measure its second order correlation function. This experiment will constitute a proofofprinciple demonstration of the utility of large Rydberg nonlinearities and marks progress towards QND measurement of photon number. [Preview Abstract] 

E01.00084: Subradiance in a gas of twolevel atoms Hanzhen Ma, Susanne Yelin As counterpart of superradiance, subradiance is a cooperative phenomenon in spontaneous emission that exhibits a decreased emission rate. Starting from the master equation of a homogeneous gas of twolevel system and its closed form where retardation effects of propagation of EM field is neglected, we develop a procedure to obtain numerical results of subradiance in such system. We studied the properties of subradiance in different optical depth. Average upperlevel population, collective induced decay rate and the coherence terms in twoatom density matrix are also calculated as a function of time. [Preview Abstract] 

E01.00085: A multiplexed quantum memory with 49 memory cells entangled with a telecom photon after 10kmlong transmission in fiber Wei Chang, Chang Li, Nan Jiang, Xiuying Chang, Luming Duan In a fiberbased longdistance quantum network, a multiplexed quantum memory with many memory cells is required to enhance the capacity of storage. Telecomwavelength transmission is also needed to minimize the exponential transmission loss in fiber. Here we report an experimental realization of a multiplexed quantum memory with 49 individually accessible memory cells entangled with a telecom photon after 10kmlong transmission in fiber. A telecom photon (1530nm) entangled with a single photon (780nm) in polarization is transmitted in a 10kmlong singlemode fiber with high transmission fidelity for the entanglement. Then the single photon (780nm) is stored into the memory cell of the multiplexed quantum memory as an atomic spinwave and the entanglement is established between the memory cell and the telecom photon after longdistance transmission. We demonstrate the high storage fidelity and the quantum property of the memory cells. This work constitutes an important step for its application in quantum information technology. [Preview Abstract] 

E01.00086: Characterization of Passively Stabilized MultiWavelength Interferometer Ian Call, Joseph Chapman, Ian Miller, Paul Kwiat In support of establishing satellitetoEarth quantum communication channels, we have constructed a passively stable delayline interferometer to facilitate phasestable production and measurement of timebin qubits in an environment subject to large temperature swings, nontrivial vibration, and severely limited maintenance access. This is accomplished using an INVAR case holding two interferometers displaced vertically, each using the same optics bearing separate optical coatings for the necessary mirrors and beamsplitters. We expect merging each set of optical components in this way will keep the relative pathlength difference due to vibration and thermal expansion to a minimum, eliminating the need for frequent finetuning. To test the phase stability in the presence of temperature and vibration fluctuations, we employ differencefrequency generation to convert between the lower and upper interferometer’s wavelengths (532 rightarrow 810 nm), thereby producing phase stable pulses created in the lower interferometer and measured in the upper one. [Preview Abstract] 

E01.00087: Blockade induced resonant enhancement of the optical nonlinearity in a Rydberg medium Annika Tebben, Clement Hainaut, Valentin Walther, Yongchang Zhang, Andre Salzinger, Renato Ferracini Alves, Nithiwadee Thaicharoen, Gerhard Zuern, Thomas Pohl, Matthias Weidemüller We report on the observation of an enhancement of the optical nonlinearity in a Rydberg gas, which is based on an interactioninduced twobody twophoton resonance under conditions of electromagnetically induced transparency (EIT). A theoretical analysis shows that the enhancement is intimately connected to resonant Rydberg dressing. We elucidate that the resonance is only uncovered when the intermediate state dynamics, that is usually ignored and adiabatically eliminated, is explicitly considered. Experimentally, we quantitatively explore the scaling of the enhancement of the thirdorder susceptibility with control parameters such as the Rabi frequency of the control beam. [Preview Abstract] 

E01.00088: Optical Kerr Effect in Organic Ultrastrongly Coupled Cavity Polaritons: Theory and Experiment Michael Crescimanno, B. Liu, S. Schwab, K. Singer Recent results from experiments in the optical dispersion of THG and the Optical Kerr effect in organic ultrastrongly coupled cavity polaritons indicate new physical processes that are understood in an expanded theory of nonlinear optical (NLO) processes in polaritonic matter. We briefly indicate the materials and experiments, summarize the most revealing experimental findings and then describe the extensions of previous theory approaches that quantify the contribution that the polaritonic states make to each of these NLO processes. [Preview Abstract] 

E01.00089: Magneticfield diagnostics in a coldatom trap using Rydberg electromagnetically induced transparency Xiaoxuan Han, Yongmei Xue, Jianming Zhao, Georg Raithel We perform an insitu, atombased measurement of a timedependent magnetic field in a gas of ultracold cesium atoms using Rydberg electromagnetically induced transparency (EIT). The threelevel ladder EIT system consists of ground ($6S_{1/2}$), excited ($6P_{3/2}$), and Rydberg levels ($48D_{5/2}$), with a total of 96 magnetic sublevels. The magnetic field we measure in the present demonstration is a superposition of an adjustable field from a set of Helmholtz coils and a rapidly decaying eddycurrent field. The EIT spectrum exhibits two dominant lines with a Zeeman splitting of $5.6~$MHz per Gauss, which are employed to measure the timedependent magnetic field. A quantum Monte Carlo wavefunction (QMCWF) approach is used to solve the quantum Master equation of the 96level problem. The QMCWF results allow us to interpret the EIT spectra in considerable detail, showing good agreement with the experiment, and to gain insight into opticalpumping and radiationpressure effects. To demonstrate the utility of the insitu, timeresolved magneticfield measurement method, we determine the decay time of the eddycurrent magnetic field at the location of the cold atom cloud. The field and time resolutions of the measurement are about $5~$mG and $100~\mu$s, respectively. [Preview Abstract] 

E01.00090: Laser Wavefront Perturbations in Atom Interferometers Jeremiah Mitchell, Timothy Kovachy, Swapan Chattopadhyay Laser wavefront perturbations act as a leading systematic in the sensitivity of phase measurement in atom interferometers. We present an analytical model of laser wavefront noise for atom interferometers. Here we examine the effect of the perturbation on the total phase measured after a 3pulse ($\pi/2  \pi  \pi/2$) atom interferometry sequence, by using a Fourier decomposition method on the amplitude perturbations of the main laser beam and propagating them through the entire sequence. A real world example of this is a periodic defect in a reflecting mirror being imprinted during laser beam reflection. Of great interest are higher order effects such as effective momentum kicks caused by the rate of change of the wavefront perturbation phase in the transverse plane to the laser propagation, $\partial\phi_{l}/ \partial x, \partial\phi_{l}/\partial z$. This model helps to build physical intuition about the size and scaling of these effects. We also explore methods to characterize and mitigate such noise in the planned MAGIS100 experiment. [Preview Abstract] 

E01.00091: A Bayesian optimization approach for determining the moleculesurface scattering matrix from surface spinecho experiments Joshua T. Cantin, Gil Alexandrowicz, Roman V. Krems While ${}^3$He spinecho experiments have been extensively used to study surfaces, replacing ${}^3$He atoms with molecules may allow for even greater insight into surface dynamics. In particular, the additional molecular degrees of freedom, such as rotation, can give us more tools with which to probe surfaces. However, these additional molecular degrees of freedom also complicate experimental interpretation. Indeed, for \textit{ortho}hydrogen, the moleculesurface scattering matrix has 81 complexvalued matrix elements that are, in general, functions of incident energy. Here, we discuss the application of our new transfer matrixbased theoretical framework to the case of \textit{ortho}hydrogen and our preliminary work in addressing the inverse scattering problem for moleculesurface scattering. As in the algorithm applied to the inverse scattering problem in quantum reaction dynamics [1], we use Bayesian optimization to determine the scattering matrix or class of scattering matrices that fit the experimental data. We also theoretically examine different experimental protocols to discern protocols more amenable to interpretation. [1] R.~A. VargasHern\'andez, Y. Guan, D.~H. Zhang, and R.~V. Krems, arXiv:1711.06376. [Preview Abstract] 

E01.00092: Entanglement State Transfer Between the Random Access Quantum Memories Chang Li, Chang Wei, Nan Jiang, Sheng Zhang, Yunfei Pu, Luming Duan The quantum network requires the high capability of interfaces and channels. The random access quantum memory (RAQM) is one promising candidate, of which the individual micro memory cells can be entangled and store the quantum state under programmable control. Here, we demonstrate a protocol to transfer the entanglement state between the two types of RAQM, which are based on the DLCZ protocol and EIT effect individually with the help of acoustooptic deflectors (AODs). The measured state fidelity indicates the entanglement is preserved during the process. The experiment results confirm that the quantum links between RAQMs is intrinsically high dimensional quantum channel, which makes a significant step towards quantum information process and quantum network. [Preview Abstract] 

E01.00093: Progress towards a dual species atomic quantum repeater node using a highfinesse fiber resonator Garrett Hickman, Matthew Ebert, Trent Graham, Xiaoyu Jiang, Sudheer Vanga, Cecilia Vollbrecht, Randall Goldsmith, Mark Saffman We present work towards a quantum repeater node based on the use of a highfinesse fiber cavity with atoms of two atomic species. Excellent coupling between the cavity and propagating light modes, and entanglement swapping between Rb and Cs atoms within the cavity, will allow the repeater to be operated with high efficiency and long memory lifetimes. In an intermediate implementation, ensembles of Rb atoms will be transported into the cavity and used for studies of the effects of surface charges on Rydberg excitation fidelities. Here we report on our progress in the use of an optical conveyor to transport atoms from a magnetooptical trap into the field mode of a highfinesse fiber cavity. [Preview Abstract] 

E01.00094: Achieving HongOuMandel Interference Between a trapped ion and Rydberg ensemble Alexander Craddock, John Hannegan, Dalia Ornelas, James Siverns, A.J. Hachtel, J.V. Porto, Steve Rolston, Qudsia Quraishi Future efforts to build quantum networks are likely to rely on the ability to interface and entangle disparate quantum systems. As a proofofconcept, we demonstrate near perfect HongOuMandel interference between photons generated by a barium ion and a rubidium Rydberg ensemble. To spectrally match the ion photon’s optical frequency to the that of the neutral atom system, we use quantum frequency conversion [1] to convert the barium ion’s photon to a wavelength matching the ensembleproduced photon. Our work forms the building blocks of a photonically linked hybrid ionRydberg ensemble quantum network. [1] J D. Siverns, J. Hannegan, and Q. Quraishi, Phys. Rev. Applied 11, 014044 (2019). [Preview Abstract] 

E01.00095: Interfacing single photons from a quantum dot embedded in a semiconductor nanowire with a lasercooled atomic ensemble confined to a hollowcore fiber Paul Anderson, Mohd Zeeshan, ShengXiang Lin, Taehyun Yoon, Divya Bharadwaj, Brian Duong, Behrooz Semnani, Jiawei Qiu, Michael Reimer, Michal Bajcsy We report our experimental progress in interfacing single photons and entangled photon pairs emitted by a quantum dot embedded in an semiconductor nanowire with an ensemble of lasercooled caesium atoms loaded into a hollowcore optical fiber. We explore controllable delays, wavelength conversion of single photons using a fourwave mixing process, and photon storage with the goal of creating a node for a quantum repeater. [Preview Abstract] 

E01.00096: Nonclassical states of light from an optical cavity Bastian Hacker, Severin Daiss, Stephan Welte, Lukas Hartung, Lin Li, Gerhard Rempe Creation of tailored nonclassical states of light is a key problem in quantum optics. Our experiment uses a trapped atom in a highfinesse optical cavity to engineer the state of an optical light pulse. To this end, the light pulse is reflected off the onesided cavity and gets entangled with the state of the atom. A subsequent measurement of the atomic state in a chosen basis projects the light pulse into one of two orthogonal subspaces. In case of coherent input light, the output is a coherentstate superposition, generally known as cat state. We produce such states with various degrees of freedom, controlled by the atom, and observe genuine quantum features such as a negative Wigner function and squeezing. Furthermore, the setup can be used as a filter for the distillation of pure single photons. We demonstrate the production of photons with arbitrary temporal shapes and a $g^{(2)}(0)$ correlation function down to 0.05. The protocol is applicable to any physical platform with an emitter coupled to the electromagnetic field, such as NV centers, quantum dots or superconducting microwave qubits. [Preview Abstract] 

E01.00097: Preparation and control of neutral atom ensemble qubits using Rydberg interactions Christopher Young, Minho Kwon, Peiyu Yang, Preston Huft, Brandon Radzom, Matthew Ebert, Thad Walker, Mark Saffman Ensemble qubits with strong coupling to photons and resilience against single atom loss are promising candidates for building quantum networks. We report on progress towards high fidelity preparation and control of ensemble qubits using Rydberg blockade. Our previous demonstration of ensemble qubit preparation at a fidelity $<$60$\%$ was possibly limited by Rydberg blockade leakage due to uncontrolled short range atom pair separation. We show progress towards ensembles with a bluedetuned 1D lattice on top of the existing reddetuned dipole trap, which will suppress unwanted Rydberg interactions by imposing constraints on the atomic separation. We study the effect of lattice insertion on the fidelity of ensemble state preparation and Rydbergmediated gates. Studies of cooperative scattering from a 1D atomic array will also be presented. [Preview Abstract] 

E01.00098: FourWave Mixing in Hot Sodium Vapor Cells with Saturated Absorption Hio Giap Ooi, Qimin Zhang, Saesun Kim, Alberto Marino, Arne Schwettmann Fourwave mixing (4WM) is a nonlinear process that can produce correlated twin beams of light, which are useful for quantumenhanced sensing and interferometry below the shotnoise limit. We generate two beams of light, known as probe and conjugate, via a doublelambda scheme in a hot sodium atomic vapor cell. Twin beams have been previously generated in Rubidium. However, sodium has a smaller hyperfine splitting, which causes the Dopplerbroadened absorption lines to overlap and thus a significant absorption of the conjugate. To reduce the resulting loss of conjugate photons, we investigate a saturated absorption method. An additional onresonance beam from our dye laser excites atoms on one of the transitions. Tuning the dye laser allows us to minimize the absorption of conjugate photons that are near to one of the atomic transitions. We present our experimental progress and characterize the dependency of the gain on the saturating beam angle and frequency. [Preview Abstract] 

E01.00099: Arbitrary Control Techniques and Applications for Spin1 Atoms Matthew Boguslawski, H M Bharath, Maryrose Barrios, Lin Xin, Michael Chapman We have developed a scheme to apply arbitrary U(3) transformations to a spin1 state. Using a multitone microwave pulse and an external light shift, we eliminate the need for more complicated, multiplestep pulse sequences to initialize or measure a particular quantum state. This technique holds promise for the arbitrary control and measurement of our system of spin1 rubidium87 atoms. Firstly, we develop a control protocol in which we can create arbitrary spin operators, via coherent construction of any U(3) operator, and apply synthetic Hamiltonians of our choosing to the atoms. Secondly, we can architect convenient projectionvalued measurements to directly measure arbitrary expectation values, giving way to the ability to perform single shot tomography and fully reconstruct a spin1 state. Beyond arbitrary control and measurement of our spin1 system, the multitone technique can be applied to a novel scheme for quantumenhanced magnetometery involving squeezed spin1 atoms. This experiment transforms a spinnematic squeezed quantum state to a magnetically sensitive state, thereby increasing our phase sensitivity by a factor equivalent to the squeezing parameter. [Preview Abstract] 

E01.00100: Quantum Networking with a Multiplexed AtomCavity Node Kevin Cox, David Meyer, Zachary Castillo, Fredrik Fatemi, Paul Kunz We describe a system which utilizes the full statespace of an atomic ensemble using angular spinwave multiplexing inside an optimized ``asymmetric'' ring cavity. This system opens the door to several important applications including multiplexed cavity QED, relatively fast quantum repeaters, and superradiant singlephoton generation. I will present current progress on these fronts. [Preview Abstract] 

E01.00101: Rydberg Interactions in a High Finesse Optical Cavity Yuanxi Chao, Akbar Jahangiri, James Shaffer We present progress on our lightRydberg atom interaction experiment in a high finesse optical cavity, $\sim$28000. We studied cavity assisted Rydberg electromagnetically induced transparency (EIT) in the presence of an interactivity electric field of $\sim$2V/cm and a magnetic field of $\sim$1G$^1$. We access Rydberg states with principle quantum numbers n $>$ 50 to study dipole blockade. We show the theoretical and experimental results for our system under such intracavity fields, where the Rydberg blockade excitations can strongly couple to the cavity modes. n $>$ 50 is suggested by our pair interaction calculations so that we can observe RydbergRydberg interactions and form superatoms inside our cavity. The Rydberg atomcavity system can be useful in controlled photon generation for quantum information processing$^2$.\\ $^1$ Jiteng Sheng et al., Phys. Rev. A \textbf{96}, 033813 (2017)\\ $^2$ Santosh Kumar et al., J. Phys. B \textbf{49}, 064014 (2016) [Preview Abstract] 

E01.00102: Precision position stabilization of acoustooptic modulator Jiaming Li, Xiao Zhang, Yang Liu, Le Luo Crossbeam optical dipole trap is widely used to trap and cool atoms. The spatial overlapping and position play an important role during the evaporative process. However, the angular instability of acoustooptic modulator affects the overlapping and introduces a position noise, which heats up the cold atomic sample dramatically. Here, we analyze the angular instability with the changing refractive index, which is caused by the uneven temperature distribution of the crystal. It is found that the angular drift is very sensitivity to the temperature gradient. In this sense, we find this drift can be suppressed out by carefully designing the temperature distribution. With our water cooling AOM setup, the angular drift is successfully reduced over 100 times, reach to 5 $\mu$rad, during the thermal transient. We also find the angular noise is compressed to 1/3 of the noncooled case, which is supposed to be good for some ultrahigh precision experiments. Furthermore, the refractive index thermal coefficient of tellurium dioxide crystal at 1064 nm is determined to be 16*10^{6} K^{1}, which is consistent with previous studies. *This work is supported by National Natural Science Foundation of China. [Preview Abstract] 

E01.00103: An optical frequency tracker for realtime monitoring and diagnostics of narrow linewidth laser systems Luis Felipe Goncalves, Rachel E. Sapiro, Georg Raithel, David A. Anderson We present an Optical Frequency Tracker (OFT) for realtime, finegrained linearization of laser scans and diagnostics of narrowlinewidth laser systems. The device allows one to accurately detect and remove nonlinearities from the frequency axis of measured spectra, including chirps and hysteresis, as well as characterize frequency drifts and jitter. This is relevant, for example, in atomic and molecular spectroscopy where the precise determination of spectroscopic lines is critical. The OFT is a compact unit that incorporates a temperaturestabilized monolithic waveguide to generate equidistant optical frequency markers that serve as a frequency ruler. The marker spacing of an individual OFT unit is typically set to a value on the order of $10$~MHz. The overall frequencymarker drift is below $10$~kHz/s. In the present demonstration we have used an OFT to characterize the performance of two laser systems: a tunable, narrowband externalcavity $1020$nm diode laser and a $780$nm DFB laser. In both cases, the OFT has been used to correct nonlinearities in the frequency scans that would otherwise have led to significant errors in spectroscopic measurements of atomic line positions. Detailed OFT performance metrics and further applications will be discussed. [Preview Abstract] 

E01.00104: Realization of a deviceindependent delayedchoice experiment using single photons Shang Yu, YongNan Sun, Wei Liu, ZhaoDi Liu, ZhiJin Ke, YiTao Wang, JianShun Tang, ChuanFeng Li, GuangCan Guo Waveparticle duality is one of the most intriguing features in quantum physics. A wellknown gedanken experiment that provides evidence for this is the Wheeler's delayedchoice experiment based on a MachZehnder interferometer. Many different versions of delayedchoice experiments have been conducted with both classical and quantum detecting devices. A recent proposal suggests that the delayedchoice experiment can be considered in the perspective of deviceindependent causal model. In this experiment, we realize this modified version with a deterministic singlephoton source. Through our results, we can examine that any twodimensional nonretrocausal classical model can be excluded in a deviceindependent manner based on the violation of dimension witness inequality. Our experiment also exhibits the benefits of studying quantum theory from the perspective of casual model. [Preview Abstract] 

E01.00105: momentum and position entanglement of photon pairs with phase structure Shi Shuai, Li Lin The entangled quantum state spanned in a spatial domain is of special importance for fundamental research in quantum information. Previous experiments on spatial entanglement were individually studied on continuous variables of momentum and position bases and discrete variables of orbitalangularmomentum (OAM) space. Momentum and position entanglement in more complex scenarios with structured wavefronts, such as vortex phases, have not been investigated, which is promising for studying the entanglement from continuous to discrete variables in infinite Hilbert space, thus providing much needed benchmarks for studying spatial highdimensional entanglement. Here, by measuring the transverse position or momentum of entanglement, we detect the arbitrary phase in the spatial domain, including the vortex phase dependence on the parity of OAM superposition and the relative phase in OAM superposition. Our demonstrations on spatial entanglement show a very promising way to explore highdimensional space and different degrees of freedom of entanglement in quantum information. [Preview Abstract] 

E01.00106: Electric field excitation suppression in cold atoms Jianing Han, Juliet Mitchell, Morgan Umstead In this article, the atom excitation suppression is studied in two ways. The first way of exploring the excitation suppression is by a DC electric field. Second, we study the excitation suppression caused by Coulomb forces. The Coulomb forces are created by ions through ionizing atoms by a UV laser, and we then watch the cold atom population change. This can be also called Coulomb blockade. The theory shows that the interaction, which causes the suppression, is primarily caused by iondipole interactions. Here the ion is created by exciting neutral cold atoms to ionized states, and the dipole is an atom. In this experiment, we use $^{85}$Rb atoms. The valence electron and the ion core are the two poles of an electric dipole. The interaction potential energy between the ion and the atom is proportional to $\frac{1}{R^2}$, and the frequency shift caused by this interaction is proportional to $\frac{1}{R^4}$, where $R$ is the distance between the ion and the dipole considered. By comparing the theory and experiment, it has been shown that the polarization of the atoms plays an important role in excitation suppression. This research can be used for quantum information storage, remote control, creating hot plasmas using cold atoms, as well as electronic devices. [Preview Abstract] 

E01.00107: Quantum simulation of magnetic polarons with dipolar superlattice gases Lushuai Cao, Xiang Gao, XiaoChun Duan We theoretically propose a strategy to simulate magnetic polarons with dipolar ultracold atoms confined in onedimensional doublewell superlattice. A spatial pseudospin mapping is used to induce an effective spin chain with the superlattice dipolar gas, and the defects in the effective spin chain is modelled by the holons and/or doublons in superlattice. We derived an effective Hamiltonian to describe the coupling between the defects and the effective spins, and demonstrate two types of polarons arising from the coupling between the defects and magnons, as well as from the coupling between defects and magnetic kinks. These two type of polarons exist in the weak and strong dipolar interaction regime, respectively. We also investigate the induced interaction between defects intermediated by the magnons and kinks. [Preview Abstract] 

E01.00108: Creating spin Lissajous maps in a spinor BoseEinstein condensate Maitreyi Jayaseelan, Justin T. Schultz, Azure Hansen, Joseph D. Murphree, Nicholas P. Bigelow We explore the connections between optical polarization fields and atomic spin degrees of freedom in a 87Rb spinor BoseEinstein condensate (BEC). The atomic Zeeman states and states of optical circular polarization are both eigenstates of spin angular momentum, allowing us to employ the language of optical polarization to describe the spatially patterned spin textures of a BEC. A pseudospin1/2 BEC is the analog of a paraxial monochromatic optical field; we create spin ellipse maps of the cloud that correspond to the polarization ellipse maps describing optical fields. Here, we extend this atomoptic analogy to study atomic analogs of bichromatic and polychromatic optical fields. The electric field vector of polychromatic fields traces out generalised Lissajous figures that may possess higher order symmetries than the polarization ellipses of monochromatic fields. Atomic populations in two separate but coherent pseudospin1/2 systems within a hyperfine manifold furnish the atomic analog of a bichromatic optical field, allowing us to create spin Lissajous maps of the cloud. We create a vortex in one spin component of the BEC using singular beams. This creates a rotation of the spin Lissajous figures around the singularity causing a knotted topology to appear in the system. [Preview Abstract] 

E01.00109: Towards quantum simulation using Rydbergexcited atoms in optical tweezer arrays Jackson Angonga, Zejun Liu, Bryce Gadway Trapped neutral atoms in optical tweezers present a versatile platform for quantum simulation, metrology and quantum information processing. We present a scheme where a synthetic dimension can be added to a onedimensional array of individually trapped $^{39}K$ atoms by exciting them to Rydberg states. A synthetic lattice of coupled internal states is created by coupling multiple Rydberg levels using microwave fields. Enhanced dipole moments associated with atoms in Rydberg states lead to strong dipoledipole interactions. These interactions and control of synthetic lattice parameters open up avenues for studying a wide range of quantum manybody phenomena. The near arbitrary ability to engineer a generic tightbinding Hamiltonian in the synthetic dimension allows new capabilities for the exploration of interaction effects in topological and disordered systems. Specifically, we will investigate formation of stable quantum strings which has been predicted to occur in such synthetic systems. [Preview Abstract] 

E01.00110: Construction of a Quantum Matter Synthesizer Mickey McDonald, Jonathan Trisnadi, Mingjiamei Zhang, Cheng Chin We report progress on the construction of a ``Quantum Matter Synthesizer,'' a new experimental platform which will have the capability to deterministically prepare twodimensional arrays of ultracold atoms with single site addressability. Precooled cesium atoms are first transferred into a science cell via a moving lattice, and then loaded into a magicwavelength, fardetuned 2D optical lattice. The cell is centered between two microscope objectives. The upper objective projects an array of optical tweezers created via a digital micromirror device (DMD) onto the atom plane. The tweezers will arrange atoms into a desired configuration. The lower objective performs in situ imaging of atoms in the lattice. To extend conventional quantum gas microscopes, we highlight results from our development of a technique for superresolution microscopy of cold atoms, enabling subwavelength imaging of atomic density distributions far below the diffraction limit. Such an imaging scheme will be integrated into our quantum matter synthesizer. [Preview Abstract] 

E01.00111: Versatile laserfree trappedion entangling gates R.T. Sutherland, R. Srinivas, S.C. Burd, D. Leibfried, A.C. Wilson, D.J. Wineland, D.T.C. Allcock, D.H. Slichter, S.B. Libby We present a general theory for laserfree entangling gates with trappedion hyperfine qubits, using either static or oscillating magneticfield gradients combined with a pair of uniform microwave fields symmetrically detuned about the qubit frequency. By transforming into a `bichromatic' interaction picture, we show that either ${\hat{\sigma}_{\phi}\otimes\hat{\sigma}_{\phi}}$ or ${\hat{\sigma}_{z}\otimes\hat{\sigma}_{z}}$ geometric phase gates can be performed. The gate operation is determined by selecting the microwave detuning. The driving parameters can be tuned to provide \textit{intrinsic dynamical decoupling} from qubit frequency fluctuations. The ${\hat{\sigma}_{z}\otimes\hat{\sigma}_{z}}$ gates can be implemented in a novel manner which eases experimental constraints. We also discuss novel gate techniques that are insensitive to heating. [Preview Abstract] 

E01.00112: Trapped ion qubit readout using a trapintegrated superconducting nanowire single photon detector S. L. Todaro, V. B. Verma, R. P. Mirin, S. W. Nam, D. J. Wineland, A. C. Wilson, D. Leibfried, D. H. Slichter Readout of the quantum state of a trapped ion qubit is accomplished by driving a stateselective optical cycling transition of the trapped ion and counting the resulting fluorescence photons; the presence or absence of fluorescence indicates the qubit state. These photons are traditionally collected with highnumericalaperture bulk optics and detected with a camera or photomultiplier tube. By integrating superconducting nanowire single photon detectors (SNSPDs) into microfabricated surfaceelectrode ion traps, we can realize a scalable architecture for spatiallyresolved, highquantumefficiency detection of fluorescence photons without the need for collection optics [1]. We report the first readout of a trapped ion qubit with a trapintegrated SNSPD, using a single $^9$Be$^+$ ion in a cryogenic surfaceelectrode trap. Fluorescence photons at 313 nm are detected by the SNSPD, with count rates comparable to those achievable with traditional bulk collection optics, and very low dark counts. We study the impact of the detector on motional heating of the ion, as well as the tolerance of the detector to rf potentials used to trap the ion. This work is supported by IARPA and the NIST Quantum Information Program. [1] D. H. Slichter et al., Opt. Express 25, 8705 (2017). [Preview Abstract] 

E01.00113: ABSTRACT WITHDRAWN 

E01.00114: Spinor BoseEinstein Condensate Interferometer within the Undepleted Pump Approximation: Role of the Initial State Jianwen Jie, Qingze Guan, Doerte Blume Most interferometers operate with photons or dilute, noncondensed cold atom clouds in which collisions are strongly suppressed. Spinor BoseEinstein condensates (BECs) provide an alternative route toward realizing threemode interferometers; in this realization, spinchanging collisions provide a resource that generates mode entanglement. Working in the regime where the pump mode, i.e., the $m=0$ hyperfine state, has a much larger population than the side or probe modes ($m= \pm 1$ hyperfine states), spinor BECs approximate SU(1,1) interferometers. We derive analytical expressions within the undepleted pump approximation for the phase sensitivity of such an SU(1,1) interferometer for general quantum states. The interferometer performance is analyzed for two specific classes of initial states, pure Fock states and coherent spin states, with singlesided seeding, and with doublesided seeding. The validity regime of the undepleted pump approximation is assessed by performing quantum calculations for the full spin Hamiltonian. Our analytical results and the associated dynamics are expected to guide experiments as well as numerical studies that explore regimes where the undepleted pump approximation is invalid. [Preview Abstract] 

E01.00115: Diamond crystal stress imaging using nitrogenvacancy centers in diamond Pauli Kehayias, Matthew Turner, David Glenn, Connor Hart, Jennifer Schloss, Raisa Trubko, Marie Wesson, Ronald Walsworth We will present our work using nitrogenvacancy (NV) defect centers in diamond to optically image the crystal stress tensor elements of a diamond sample. Motivated by our ongoing progress using 2D layers of NV centers for magnetic microscopy in geology and biology, we will discuss how strain defects in a diamond crystal can spoil the magnetic sensitivity and give rise to false magnetic features. We will describe our technique for reconstructing the diamond stress tensor from opticallyinterrogated NV resonance frequencies, validate and compare with measurements from a builtin birefringence imager, catalog the types of strain features common to our synthetic diamond chips, and discuss how this work enables improved NV magnetic and stress sensing. [Preview Abstract] 

E01.00116: Quantum sensing at high pressures using the nitrogenvacancy center T. O. Hoehn, S. Hsieh, P. Bhattacharyya, C. Zu, T. Mittiga, T. Smart, F. Machado, B. Kobrin, N. Rui, M. Kamrani, S. Chatterjee, S. Choi, M. Zaletel, V. Struzhkin, J. Moore, V. Levitas, R. Jeanloz, N. Yao The nitrogenvacancy (NV) center in diamond is a promising nanoscale sensor for temperature, strain, electric and magnetic fields. Employing this suite of sensing techniques in a high pressure environment represents an important challenge at the interface of fields ranging from geophysics to condensed matter. To this end, we introduce a new sensing platform based upon directly integrating NV centers into the culet of diamond anvil cells (DAC)  one of the workhorses of highpressure science. We demonstrate the capability of this platform by performing diffractionlimited imaging of stress fields, quantifying all six (normal and shear) stress tensor components, as well as vector magnetic fields in iron and gadolinium up to pressures of 60 GPa and for temperatures ranging from 25 to 340 K. In addition to DC vector magnetometry, we highlight a complementary NVsensing modality using $T_1$ noise spectroscopy. [Preview Abstract] 

E01.00117: Timedomain grating with a periodically driven qutrit Yingying Han, TieFu Li, Wenxian Zhang, J. Q. You, Franco Nori Physical systems in the time domain may exhibit analogous phenomena in real space, such as time crystals and timedomain Fresnel lenses. We report the experimental realization of timedomain grating using a superconducting qutrit in periodically modulated probe and control fields via two schemes: Simultaneous modulation and complementary modulation. Both experimental and numerical results exhibit modulated AutlerTownes (AT) and modulationinduced diffraction (MID) effects. Theoretical results also confirm that the peak positions of the interference fringes of AT and MID effects are determined by the usual twolevel relative phases, while the observed diffraction fringes, appearing only in the complementary modulation, are however related to the threelevel relative phase. Further analysis indicates that such a singleatom timedomain diffraction originates from the correlation effect between the two timedomain gratings. Moreover, we find that the widths of the diffraction fringes are independent of the controlfield power. Our results shed light on the experimental exploration of quantum coherence for modulated multilevel systems and may find promising applications in fast allmicrowave switches and quantumgate operations in the strongdriving regime. [Preview Abstract] 

E01.00118: Progress towards a Hybrid Rydberg Atom, Superconductor Quantum Interface Juan Bohorquez, Sebastian Malewicz, Donald Booth, Yujun Choi, Robert McDermott, Mark Saffman \indent Hybrid quantum computing schemes bridge disparate quantum technologies in order to construct machines with fast quantum gates and long coherence times. We present progress on our effort towards a hydbrid quantum interface between single cold Rydberg atoms and a Superconducting coplanar waveguide (CPW) resonator. We implement our hybrid interface by trapping a single ground state Cesium atom in a $4$K cryostat, then vertically transporting it into the resonator interaction region. We use a novel two photon excitation via the $6S_{1/2} \rightarrow 5D_{5/2}$ quadrupole transition to excite $nP_{3/2}$ Rydberg states where there exists strong electricdipole coupling between the atom and the resonator.\\ \\ \indent We have completed construction of the cryostat and the UHV chamber that houses the atoms and chip. We demonstrate single atom trapping results and progress towards initialization and quantum control of atomic qubits in terms of optical pumping, single qubit rotations, and Rydberg excitations. [Preview Abstract] 

E01.00119: Towards a Steadystate Atom Laser ChunChia Chen, Shayne Bennetts, Rodrigo González Escudero, Benjamin Pasquiou, Florian Schreck So far BECs and atom lasers have only been demonstrated as the product of a time sequential, pulsed cooling sequence. For applications such as next generation atomic clocks, superradiant lasers or atom interferometers for gravitational wave detection, a steadystate source of degenerate atoms offers great advantages. We present an apparatus that produces a steadystate strontium sample with a phasespace density approaching degeneracy, thus taking a critical step towards demonstrating steadystate atom lasers. Our machine achieves this by simultaneously cooling atoms in spatially separated regions on both the 30MHz and 7.4kHz linewidth Sr transitions [1]. We then continuously load a dipole trap where a Stark shift protected dimple collects the coldest atoms. We also demonstrate operation on the $^{\mathrm{87}}$Sr isotope which is of particular interest for atomic clocks. Finally, we demonstrate a new deceleration method [2] that might bridge the gap between the unity phasespace density now demonstrated and an eventual steadystate BEC [1] S. Bennetts et al., Phys. Rev. Lett. 119, 223202(2017). [2] C.C. Chen et al., arXiv:1810.07157 (2018). [Preview Abstract] 

E01.00120: DEGENERATE GASES AND MANYBODY PHYSICS 

E01.00121: Vortex Physics in Hollow BoseEinstein Condensates Karmela Padavic, Kuei Sun, Courtney Lannert, Smitha Vishveshwara We present studies of vortex physics in hollow spherically symmetric BoseEinstein condensates (BEC). When BECs are stirred or rotated, due to the relation between the velocity field of the condensate and the phase of its wavefunction, vortices are generated and the remainder of the condensate remains irrotational. The behavior of such vortices and their formation of lattices at high rotation speeds have been extensively studied experimentally and theoretically. In the hollow, spherically symmetric BEC case which we consider here, a major difference is the presence of two boundary surfaces. This BEC structure supports generation of vortices at lower rotation speeds than in the fully filled case. We find that vortex lines parallel to the rotation axis located at an offset with respect to it cannot be stationary. If vortex lines are positioned along the rotation axis, however, they can be stationary but are not fully straight at low rotation speeds i.e. they nucleate as vortex tubes with ends bent towards condensate boundaries. As a limiting case, we also study an infinitesimally thin BEC shell and determine the attractive force between pairs of vortices on such a surface. [Preview Abstract] 

E01.00122: Fingering instabilities in a twocomponent dipolar BoseEinstein condensate KuiTian Xi, Tim Byrnes, Hiroki Saito We study fingering instabilities and pattern formation at the interface of an oppositely polarized twocomponent BoseEinstein condensate (BEC) with strong dipoledipole interactions (DDIs) in three dimensions. It is shown that the rotational symmetry is spontaneously broken by fingering instabilities when the DDIs are strengthened. Frogshaped and mushroomshaped patterns have been shown with different strengths of the DDIs. A Bogoliubov analysis gives a qualitative understanding of the interfacial instabilities of the two dipolar BECs, and a dispersion relation similar to that in classical fluids is obtained. Spontaneous density modulation and dipolar domain growth in the dynamics have also been demonstrated, in which we have analyzed the characteristic sizes of the dipolar domains corresponding to different patterns at the initial and later times in the evolution. We have also investigated the parameter dependence of the ground states, and found that the droplet patterns are formed due to the population imbalance in the two components. Labyrinthine patterns grow as the trap ratio increases, and a striped phase appears as the angle of tilted polarization increases. Our findings may establish further connections between superfluids and classical fluids. [Preview Abstract] 

E01.00123: Bose Polarons in an ultracold mixture of $^{\mathrm{87}}$Rb and $^{\mathrm{23}}$Na atoms Lintao Li, Zhichao Guo, Fan Jia, Dajun Wang We report the progress on investigating the Bose polaron problem with a mixture of ultracold BoseBose mixture of $^{\mathrm{23}}$Na and $^{\mathrm{87}}$Rb atoms. We prepare the Bose polaron by immersing heavy $^{\mathrm{87}}$Rb impurities in the BoseEinstein condensate of $^{\mathrm{23}}$Na. Using radio frequency spectroscopy, we investigate the polaron injection spectrum and its dependence on the impurity concentration while the impurityBEC interaction is tuned by a Feshbach resonance. In particular, we plan to study the impurity concentration dependence of polaron energy, which may provide more information on polaron problem beyond the properties of single polaron with zero momentum. [Preview Abstract] 

E01.00124: Tunneling Times and Studying the Effects of Dissipation David Spierings, Ramon Ramos, Joseph McGowan, Aephraim Steinberg How much time does a tunneling particle spend in the barrier region?~ An answer to this question may be defined by considering a ``weak measurement'' in the sense of Aharonov, Albert, and Vaidman.~ A Larmor clock, which uses a spin degree of freedom to keep time, can implement such a measurement [1] and this experiment has recently been performed in our group. We now consider probing the quantum/classical transition by studying what happens when the Larmor measurement is made "strong" and/or under the influence of strong interactions and engineered dissipation [2, 3]. [1] Steinberg, A. M. Time and history in quantum tunneling. \textit{Superlattices and Microstructures}, \textit{23}(34), 823832. (1998). \underline {http://doi.org/10.1006/spmi.1997.0543} [2] Potnis, S., Ramos, R., Maeda, K., Carr, L. D., {\&} Steinberg, A. M. (2017). InteractionAssisted Quantum Tunneling of a BoseEinstein Condensate out of a Single Trapping Well. \textit{Physical Review Letters}, \textit{118}(6), 15. \underline {http://doi.org/10.1103/PhysRevLett.118.060402} [3] Steinberg, A. M. (1999). On energy transfer by detection of a tunneling atom. Korean Physical Society 35 (3), 122. (\underline {http://arxiv.org/abs/quantph/9904098}) [Preview Abstract] 

E01.00125: Fractional Quantum Hall Physics in Materials Made of Light Claire Baum, Nathan Schine, TianXing Zheng, Ningyuan Jia, Logan W. Clark, Jonathan Simon Ordinarily, photons do not interact with each other. However, atoms can be used to mediate photonphoton interactions, raising the prospect of forming synthetic materials and quantum information systems from photons. By dressing photons with atomic Rydberg states, we create strongly interacting Rydberg polaritons whose spatial profiles are determined by the modes of an optical cavity. Polaritons in a single spatial mode exhibit their strong interactions via blockade, an effect in which only one photon can transmit through the cavity at a time. Enabling these polaritons to move between multiple spatial modes of the optical cavity allows the polaritons to order themselves into stronglycorrelated states. We present the initial experiments using Rydberg polaritons in a carefully tailored set of cavity modes to study stronglycorrelated materials made of photons such as Laughlin states, the ground states of a fractional quantum Hall system. [Preview Abstract] 

E01.00126: Drivendissipative coupled Ising models: a new nonequilibrium universality class Jeremy T. Young, Michael FossFeig, Alexey V. Gorshkov, Mohammad F. Maghrebi Drivendissipative systems can potentially exhibit nonequilibrium phenomena that are absent in their equilibrium counterparts. However, phase transitions present in these systems generically exhibit an effectively classical, equilibrium behavior in spite of their nonequilibrium origin. We investigate an experimentally motivated model where two Isinglike order parameters interact and form a multicritical point. Using perturbative renormalization group techniques, we show that a pair of inherently nonequilibrium multicritical points emerge. These nonequilibrium multicritical points exhibit a variety of exotic phenomena with no counterpart in equilibrium, including spiraling phase boundaries, the emergence of discrete scale invariance rather than the more familiar continuous scale invariance, and the violation of the fluctuationdissipation theorem at all length scales, resulting in a system which becomes hotter and hotter at longer and longer wavelengths. Furthermore, we find that for more complex order parameters with a different form or symmetry, additional nonequilibrium multicritical points emerge. [Preview Abstract] 

E01.00127: Realization of large ${}^{7}$Li BoseEinstein condensates using gray molasses Kyungtae Kim, SeungJung Huh, Kiryang Kwon, Jaeyoon Choi The ultracold ${}^{7}$Li atoms are a good candidate for studying nonequilibrium phenomena by means of relatively light mass and the broad Feshbach resonance. In this poster, we report an apparatus that produces BoseEinstein condensates with $ 2.7 \times 10^{6} $ atoms in 11s. To have rapid evaporation cooling in a magnetic trap, we adopt $D_{1}$ gray molasses [1] that cools atoms trapped in a magnetooptical trap to 25$\mu$K. Runaway evaporation cooling is achieved in a plugged quadrupole magnetic trap, where the Majorana atom loss is fully suppressed by a repulsive optical barrier. The BECs are obtained in a crossedoptical dipole potential by evaporation near the Feshbach resonance. For efficient evaporation, we apply a vertical field gradient, tilting the optical potential to reduce potential depth [2]. \\ [1] A. T. Grier, I. FerrierBarbut, B. S. Rem, M. Delehaye, L. Khaykovich, F. Chevy, and C. Salomon, Phys. Rev. A  At. Mol. Opt. Phys. 87, 1 (2013).\\ [2] C. L. Hung, X. Zhang, N. Gemelke, and C. Chin, Phys. Rev. A  At. Mol. Opt. Phys. 78, 1 (2008). [Preview Abstract] 

E01.00128: Breaking the fluctuationdissipation relation by universal transport processes Asier Pi\~neiro Orioli, J\"urgen Berges Universal phenomena far from equilibrium exhibit additional independent scaling exponents and functions as compared to thermal universal behavior. For the example of an ultracold Bose gas we simulate nonequilibrium transport processes in a universal scaling regime and show how they lead to the breaking of the fluctuationdissipation relation. As a consequence, the scaling of spectral functions (commutators) and statistical correlations (anticommutators) between different points in time and space become linearly independent with distinct dynamic scaling exponents. As a macroscopic signature of this phenomenon we identify a transport peak in the statistical twopoint correlator, which is absent in the spectral function showing the quasiparticle peaks of the Bose gas. [Preview Abstract] 

E01.00129: Emergent periodic and quasiperiodic lattices on surfaces of synthetic Hall tori and synthetic Hall cylinders Yangqian Yan, ShaoLiang Zhang, Sayan Choudhury, Qi Zhou Synthetic spaces allow physicists to bypass constraints imposed by certain physical laws in experiments. Here, we show that a synthetic torus, which consists of a ring trap in the real space and internal states of ultracold atoms cyclically coupled by LaguerreGaussian Raman beams, could be threaded by a net effective magnetic flux through its surfacean impossible mission in the real space. Such synthetic Hall torus gives rise to a periodic lattice in the real dimension, in which the periodicity of density modulation of atoms fractionalizes that of the Hamiltonian. Correspondingly, the energy spectrum is featured by multiple bands grouping into clusters with nonsymmorphic symmetry protected band crossings in each cluster, leading to braidings of wavepackets in Bloch oscillations. Our scheme allows physicists to glue two synthetic Hall tori such that localization may emerge in a quasicrystalline lattice. If the LaguerreGaussian Raman beams and ring traps were replaced by linear Raman beams and ordinary traps, a synthetic Hall cylinder could be realized and deliver many of the aforementioned phenomena. [Preview Abstract] 

E01.00130: Ground state phases of a quasi2D BEC of rigid rotor molecules via Bogoliubov meanfield theory Nathaniel Chapman, Seth Rittenhouse, Ryan Wilson, Brandon Peden We investigate the quadrupolar properties of the ground state and lowenergy excitations of a BoseEinstein condensate of rigid rotor molecules confined harmonically in two dimensions. A gradient field is applied that induces molecular quadrupole moments, and the molecules interact via quadrupolequadrupole forces. Via a Bogoliubov meanfield analysis, we identify a secondorder phase transition between liquidcrystallike uniaxial and biaxial nematic phases driven by the strength of the quadrupolar interactions and associated with the spontaneous symmetrybreaking of azimuthal symmetry in the plane. We investigate the stability of these phases by way of the dispersion relations of the lowenergy excitations. [Preview Abstract] 

E01.00131: ShellGeometry BoseEinstein Condensates in Microgravity Ryan Carollo, Maxwell Gold, Xiaole Jiang, Karmela Padavic, Smitha Vishveshwara, Courtney Lannert, David Aveline, Nathan Lundblad NASA's Cold Atom Laboratory (CAL) provides investigators the unique capability of producing BECs in orbit, where the perpetual freefall environment enables experiments largely free of gravitational perturbation. We use this environment to study radiofrequencydressed condensates in a spherical or ellipsoidal shell (a ``bubble''), a geometry that is technically difficult to achieve on Earth. We discuss initial results, operating procedures related to expansion adiabaticity and radiofrequency ramps, trap inhomogeneity, and possible mitigating techniques permitting a topologicallyconnected shell condensate. [Preview Abstract] 

E01.00132: Twocomponent dipolar Fermi gases in a spherically symmetric harmonic trap Takahiko Miyakawa, Shin Nakamura, Hiroyuki Yabu We study the ground state of twocomponent dipolar Fermi gases in a spherically symmetric harmonic trap at zero temperature. We obtain a phase diagram of the system with equal but opposite values of the magnetic moment on the basis of the ThomasFermivon Weizsäcker approximation. We find that a symmetrybroken phase separation emerges. We also consider a dipolar Fermi mixture of Er and Dy atoms and obtain the characteristics of density profiles of two atoms. [Preview Abstract] 

E01.00133: Interactions and collective excitations in a SU($N$) Fermi gas Zejian Ren, Bo Song, Chengdong He, Elnur Hajiyev, Entong Zhao, Qianhang Cai, Jeongwon Lee, GyuBoong Jo Ultracold fermions with SU($N>$2) symmetry offer a unique opportunity to study quantum dynamics and interaction effects in the large spin systems that have no analogue in condensed matter physics. In this poster, we present a set of experiments on the measurement of contact parameters and collective excitations with a SU($N$) Fermi gas of $^{173}$Yb atoms. First, we explore the shortrange interaction effect via Tan's contact parameters in a multicomponent Fermi gas with SU($N>$2) symmetry. The $s$wave contact parameter is experimentally measured by recording the highmomentum tail of weakly interacting fermions. For a tunable number of spin component $N$ with a fixed number of atoms per component, we verify the linear increase in the contact with $N$ providing experimental confirmation of SU($N$) interactions. Furthermore, we explore the momentum distribution of SU($N$) fermions at the low momentum regime. Next, we measure collective excitations of a harmonically trapped twodimensional SU($N$) Fermi gas. Various collective modes are investigated with a tunable number of spin component $N$ showing a decrease in the ratio of quadruple and dipole mode with $N$. Our work will pave the way for the experimental study of interacting SU($N$) Fermi gases with large spin. [Preview Abstract] 

E01.00134: Topological Excitations in Spin2 BECs Alina Blinova, Tuomas Ollikainen, Mikko M{\"o}tt{\"o}nen, David Hall Spinor BoseEinstein condensates (BECs) support a variety of magnetic phases that break the symmetry of the full interaction Hamiltonian. The different broken symmetries of the order parameter permit a wide variety of topological excitations that extend beyond the familiar quantized vortices. For example, in spin1 condensates the symmetry of the ferromagnetic phase supports skyrmions, whereas the polar magnetic phase supports both knots and monopoles. While spin1 BECs have recently received considerable attention, topological excitations in spin2 condensates remain largely unexplored. Here we report the successful experimental realization of knots, monopoles and vortices in the uniaxial nematic and ferromagnetic phases of a spin2 $^{87}$Rb BEC, as well as in the F=1 and F=2 superposition. Our experiments serve as the starting point in the experimental study of exotic excitations within the rich landscape of these magnetic phases. [Preview Abstract] 

E01.00135: Dynamics of superfluid to Mottinsulator phase transitions in spinor gases Zachary Shaw, Lichao Zhao, Zihe Chen, Jared Austin, Yingmei Liu Spinor BoseEinstein condensates possess a spin degree of freedom, leading to a range of phenomena absent in scalar condensates. One remarkable example is the existence of firstorder superfluid (SF) to Mottinsulator (MI) quantum phase transitions in antiferromagnetic spin1 spinor condensates. We experimentally study the dynamics of SFMI phase transitions in antiferromagnetic spinor gases confined by cubic optical lattices. Our studies are performed in a quantum quench scenario beginning with spinor gases in the longitudinal polar superfluid state. In this scenario, the lattice potential is quenched to a very large value, which completely turns off the tunneling among adjacent lattice sites to ensure atoms enter into the MI phase. Spin population oscillations are observed after fast quenches and adiabatic quantum phase transitions are confirmed in sufficient slow lattice ramp sequences, while complicated spin dynamics appear at intermediate quench speeds. Our observations at the fast and slow quenches can be well explained by known theoretical models, however, a phenomenological model is introduced to describe the continuous quenches at intermediate speeds. [Preview Abstract] 

E01.00136: Dynamical Fermionization of a 1D Bose gas Yuan Le, Joshua Wilson, Neel Malvania, Yicheng Zhang, Wei Xu, Lin Xia, Marcos Rigol, David Weiss We observe the evolution of the momentum distributions of strongly interacting onedimensional Bose gases as they expand while still confined in 1D. The momentum distribution evolves from the initial bosonic shape to that of a noninteracting Fermi gas in the same trap, in agreement with numerical simulations of hardcore bosons [1,2]. We also operate the experiment in the intermediate coupling regime. In additional work, we observe the predicted oscillation between bosonic and fermionic momentum distributions after a sudden quench of the trap frequency [2]. [1] M. Rigol et al., PRL 94, 240403 (2005). [2] A. Minguzzi et al., PRL 94, 240404 (2005). [Preview Abstract] 

E01.00137: Radiofrequency spectroscopy of lowdimensional Fermi gases near swave and pwave Feshbach resonances Kenneth Jackson, Scott Smale, Ben Olsen, Joseph Thywissen We investigate the effects of dimensionality and orbital parity on pairing in a degenerate Fermi gas of potassium atoms near a Feshbach resonance. Dimensionality is controlled by loading atoms into one or two optical lattices, to create ensembles of 2D or 1D samples, respectively. At various swave or pwave scattering lengths, we perform radiofrequency spectroscopy, which can associate or dissociate Feshbach dimers, cause boundtobound transitions, or reveal the contact. From these spectra, we can measure the energetic widths of resonances, the nature of the pair wave function, and the strength of shortrange correlations in the gas. By comparing spectra in different confinement geometries, we test predictions on the interplay between dimensionality and pairing. [Preview Abstract] 

E01.00138: ManyBody Bose Polaron Dynamics: Mass Renormalization, Induced Interactions and Orthogonality Catastrophe Simeon Mistakidis, Artem Volosniev, Garyfallia Katsimiga, Georgios Koutentakis, Nikolaj Zinner, Thomas Busch, Peter Schmelcher We unravel the correlated nonequilibrium dynamics of one dimensional harmonically trapped Bose polarons. Utilizing manybody simulations we demonstrate that inhomogeneity can be taken into account by an effective onebody model where both the mass and the string constant are renormalized [1]. Moreover, we inspect the dynamical dressing of spinor impurities when coupled to a bosonic environment. Monitoring the structure factor of the system three distinct dynamical regions arise upon increasing the interspecies interaction [2]. The polaron formation is imprinted on the spectral response of the system. For strong interactions an orthogonality catastrophe occurs and the polaron picture breaks down. Then, a dissipative motion of the impurity takes place leading to a transfer of energy to its environment and in turn signaling the presence of entanglement. The occurrence of induced interactions is exposed and their effect in the dynamics of several observables is identified. [1] arXiv:1809.01889 (2018). [2] arXiv:1811.10702 (2018). [Preview Abstract] 

E01.00139: Parametric excitation of a BoseEinstein condensate with modulated interactions De Luo, Jason H. V. Nguyen, Patrick Bagge, Randall G. Hulet Faraday waves are standing wave patterns that appear on the surface of a periodically driven medium. They have been observed in a BoseEinstein condensate (BEC) by modulating the trapping potential\footnote{P. Engels, C. Atherton, and M. A. Hoefer, Phys. Rev. Lett. 98, 095301 (2007).}. In this work, we explore the Faraday wave phenomenon in a quasi1D BEC by modulating the atomic interaction. We create a $^{7}$Li BEC in the $1,1\rangle$ state and modulate the scattering length directly by the Feshbach resonance. We have observed two very different regimes. When the modulation frequency is comparable to the radial trapping frequency and the modulation amplitude is small, we observe the Faraday waves. Their spatial frequency as a function of the modulation frequency and amplitude is in good agreement with meanfield theory. On the other hand, when the modulation frequency is much smaller than the radial trap frequency, the condensate evolves into a granulated state, where grains of atoms form with varying sizes. We find that the granulation is incompatible with meanfield theory, but is welldescribed by a beyond meanfield approach, which hints that the granulation is concurrent with manybody correlations. [Preview Abstract] 

E01.00140: Apparatus for Spin and Heat Transport in Fermi Gases Ian Crawley, Christopher Angyal, Dadbeh Shaddel, John Griffin, Mari McPheron, Rebecca Davis, Ding Zhang, Ariel Sommer Transport properties provide an important tool to characterize manybody systems. We propose measurements of spin transport in strongly interacting Fermi gases that will test a proposed lower bound on diffusivity as well as predicted signatures of a pseudogap phase. Our experimental apparatus will utilize a homogeneous Fermi gas separated into three regions: a sample and two reservoirs. Nonequilibrium initial conditions in the reservoirs will drive a spin current through the sample, enabling detailed measurements of the spin diffusivity. Our experimental approach can be extended to measurements of heat transport and nonequilibrium states. [Preview Abstract] 

E01.00141: Towards quantum gas microscopy of fermions in pbands Peter Schauss Quantum gas microscopes have taken the study of Hubbard physics in optical lattices to a new level, enabling singlesite and singleatom resolved detection of strongly correlated states like Mott insulators and antiferromagnets. So far, these experiments have focused on the study of manybody states in the ground band of square lattices. Using lithium 6, a fermion with tunable interactions and fast tunneling due to its low mass, we plan to widen the focus of quantum gas microscopy to fermions in pbands. Higher bands are an important ingredient in Hubbard models for real materials and lead to new effects like orbital ordering. Competition between orbital ordering and the wellknown spinordering can lead to exotic quantum phases. On the Poster we will present future plans and the current status of the experimental setup. It was designed to obtain high reliability, a fast cycle time and improved optical access. [Preview Abstract] 

E01.00142: Progress towards experimental realization of 5fold twodimensional quasicrystals of ultracold atoms Jahnavee Mittal, Theodore A. Corcovilos Quasicrystals are nonperiodic arrangements of atoms having no translational symmetry but nonetheless possessing longrange order. The material properties of quasicrystals, particularly their lowtemperature behavior, defy easy theoretical description  they are a chimera of ordered and disordered behavior. We present our progress in constructing an experiment to investigate the low temperature phases of quasicrystals by building an analogous system of ultracold Rb87 atoms in a 2d optical potential. Our compact optical setup for creating quasicrystal optical potentials with 5fold symmetry uses interference of nearly copropagating beams rather than the more common method having the optical lattice beams in a plane. We discuss the optical design through numerical simulations and a characterize a prototype system, and describe how our setup can generate phason excitations and quantized transport. We also present our vacuum, optical, and electronic design and report on the construction progress. [Preview Abstract] 

E01.00143: Quantum Hall Physics with Ultracold Atoms in Lattices with MultiplyConnected Topology Anna Faretty, Gerald Curran, Jacob Christ, Kunal Das We demonstrate that all the salient features of the Harper model associated with the Quantum Hall effect can be implemented with ultracold atoms trapped in a bichromatic ringshaped lattice; such features include criticality, localization transition and edge states. Using realistic sinusoidal lattice potentials rather than assume the idealized tightbinding picture, we determine the optimal conditions necessary to realize the critical point where the spectrum becomes fractal, and we identify the nature and cause of the departures from the discrete model predictions. We explore generalizations of the model to more complex configurations with multiplyconnected topologies, such as disk, cylinder or torus, with a view to implementation with cold atoms in designer lattices, and we examine the spectrum as well as dynamical effects. [Preview Abstract] 

E01.00144: Orbitnematic coupling and nematic density waves in antiferromagnetic spin1 condensates Di Lao, Chandra Raman, Carlos Sa de Melo We propose the creation of artificial orbitnematic coupling in spin1 sodium condensates via a suitably designed microwave chip that produces a spatially dependent quadratic Zeeman shift, which is parametrized by the amplitude of the constant component $q$ and the spatially varying component $\Omega$. We construct the phase diagram of $q$ versus $\Omega$ and show that three quantum phases emerge. The first one is a conventional easyaxis nematic BoseEinstein condensate, and the other two are easyplane nematic condensates with either singlewell or doublewell structure in momentum space. By including spindependent and spinindependent interactions, we also obtain the low energy excitation spectra in these three phases. Furthermore, we demonstrate that the momentumspace singlewell and doublewell easyplane nematic phases correspond, respectively, to realspace commensurate and incommensurate nematic density waves. [Preview Abstract] 

E01.00145: COLD ATOMS, IONS, MOLECULES, AND PLASMAS 

E01.00146: Atom Counting by Hyperfine Raman Optical Pumping in Cold Rubidium 87 Joshua Carter, Brent Jones, Stetson J. Roof, Kasie J. Kemp, M. D. Havey, I. M. Sokolov, D. V. Kupriyanov We report studies of interaction of a weak probe beam and a small, cold cloud of $^{87}$Rb atoms. For this configuration, a range of complex phenomena, such as super and subradiance, have been observed. These occur typically at greater optical depths, where atoms interact cooperatively with both the incident light and the fields from all the other scatterers in the system. A recent paper has reported that cooperative interactions can also lead to suppression of hypefine Raman transitions in a cold and dense lattice of $^{87}$Rb atoms [1]. The same hyperfine transitions may also be used to count the number of atoms in the sample, via optical pumping [2]. Our measurements show that this method is effective for weak probing of a magneto optical trap, and holds over a range of detuning, atom density, and probe intensity. However, random walk simulations suggest that at higher optical depths, multiple scattering can cause an overcounting effect of the sample, modifying the optical decay rates, see also [3]. We present low density benchmark measurements of atom number and optical decay rates, along with simulation data at higher optical depth.\\ \\$[1]$ S. Machluf, et al., arXiv:1804.09759.\newline $[2]$ Y.C. Chen, et al., Phys. Rev. A 64, 1 (2001).\newline $[3]$ R. R. Mhaskar, et al., EPJ D 41, 221 (2006). [Preview Abstract] 

E01.00147: Observation of a quasionedimensional SternGerlach effect Kevin Melin, Pavel Nagornykh, Yu Lu, Logan Hillberry, Yi Xu, Mark Raizen We demonstrate a realization of a quasionedimensional SternGerlach effect on a supersonic beam of lithium7 atoms. In the original work, performed by Otto Stern and Walter Gerlach in 1922, a collimated beam of silver atoms was split into two distinct lines after passing through a permanent, spatially varying magnetic field. In addition to the splitting in one dimension, divergences in the atomic beam were expected in all dimensions due to the field configuration employed. In our work, we show that a combination of a pulsed magnetic field gradient plus a strong bias field can produce a nearly divergencefree quasionedimensional force. This technique has applications towards new cooling methods and earthbased microgravity experiments. [Preview Abstract] 

E01.00148: Coherent State Description of the Bichromatic Force Harold Metcalf The usual description of the bichromatic force (BF) has always been in terms of atomic dressed states in a twofrequency field.\footnote{H. Metcalf, Rev. Mod. Phys. {\bf 89} 041001 (2017) and its Ref's.} However, laser cooling with the BF in the absence of spontaneous emis\sion\footnote{C. Corder et al., Phys. Rev. Lett. {\bf 114} 043002 (2015).} has led to entropy questions. We propose a description of the BF in terms of quantized fields to address such questions. Clearly number state descriptions of the two, fewmW light fields are not appropriate, so we describe them using coherent states. The description starts by considering these light fields first and bringing in the atoms afterward, just the reverse sequence of previous descriptions. The coherent states $\alpha_k\rangle$ are defined in the customary way as $\alpha_k \rangle \equiv {e^{\alpha_k^2/2}} \sum_{n_k}\{ \alpha^{n_k} /\sqrt{n_k!}\,\} \, n_k\rangle$, where $k$ is a label for either red or blue detuned light. As usual, $\alpha_k\rangle $ represents a coherent state, $\alpha_{k}$ is a complex number, and $n_k\rangle$ represents a number state corresponding to the summation integer $n_k$. The resulting eigenenergies are identical to those found previously and the description of the BF follows naturally.$^2$ [Preview Abstract] 

E01.00149: Modified GUI for controlling atomic physics experiments Elisha Haber In cold atom physics experiments often need many different pieces of hardware to be controlled with microsecond precision. The Cicero Word Generator, which is a freely available control software developed at MIT, was modified for use in our laboratory. In Cicero, a graphical user interface (GUI) is used to design sequences and to communicate with hardware servers that share a common clock. This allows all events to be synchronized between the different servers. The most important modifications to the GUI include giving the user greater freedom in creating sequences, automating the process of running multiple sequences in series or parallel, allowing the user to implement safety protocols using analog input hardware channels, and adding a more comprehensive data backup system. This modified version of the Cicero Word Generator will eventually be used to control the ultracold atom experiments performed in our laboratory. [Preview Abstract] 

E01.00150: Zeeman slowing of an atomic beam in a strong, dipolar background field Leo Nofs, Eric Paradis, Georg Raithel We have designed a modified Zeeman slower that will be used to source a specialized highmagneticfield (highB) atom trap. The trap is a superconducting IoffePritchard style trap that operates in the PaschenBack regime (2.0 T–3.0 T) and currently works with rubidium [1]. In earlier experiments the trap was loaded using a pyramidal MOT, which had an atomic flux of $10^7 s^{1}$. We aim to replace the MOT with a Zeeman slower, to increase the atom flux by a factor of 1000 or more. The resultant increase in atom and plasma densities in the highB trap will allow us to study phenomena in dense, cold, magnetized plasmas, such as strong coupling, shock fronts, and collisions. This modified Zeeman slower must incorporate the strong, inhomogeneous bias magnetic field from the highB trap. We have created a model which generates a set of solenoids (using current, length, and thickness as parameters). This model includes an optimization algorithm to obtain the best fit for the targeted field profile. This design uses the modular nature of the solenoids to allow for the slowing and trapping of either rubidium or strontium by applying separate sets of optimized current values. This Zeeman slower design also allows for operation with or without the highB bias field. [1] PRL 94, 073003 [Preview Abstract] 

E01.00151: Algorithmic cooling of a manybody system. Zhihui Wang, Melina Filzinger, Yue Shi, Frank Moscatelli, Jiehang Zhang Computers, quantum and classical alike, require an initialization to a state with high purity prior to performing any computation task. This operation reduces information entropy to nearly zero, which can be achieved by either shifting charges in a classical transistor, or by optically pumping individual atoms to initialize an atomic quantum computer. In both cases the entropy is removed by coupling to an effective external bath. An alternative method is to gain information, compute the direction to minimize entropy, and perform feedback operations. We show this algorithmic cooling in an example manybody system: ions in a charged particle trap. This technique can be readily applied to different manybody systems as it is agnostic to the trapped particle species. [Preview Abstract] 

E01.00152: Towards Continuouswave Laser Cooling for Antihydrogen Wayne Huang, Tharon Morrison, Nathaniel McDonough, Gerald Gabrielse Antihydrogen synthesis opens new avenues for precision measurements for investigating the antimattermatter asymmetry. The narrow line of the 1S2S transition in hydrogen and antihydrogen provides an excellent test for this asymmetry. Precision hydrogen spectroscopy is typically performed in a beam configuration. This is not applicable for antihydrogen due to constraints in the ability to produce and contain it. Laser cooling is thus a prerequisite for precise antihydrogen spectroscopy in a neutral particle trap. However, the required cooling laser wavelength, Lymanalpha (121.56 nm for 1S2P transition), is difficult to produce coherently. A pulsed source can be used to achieve few microwatts of average power [1], but the broad linewidth limits the cooling performance. Based on [2] where 20 nanowatts of Lymanalpha was demonstrated, we are working towards improvements to microwatt coherent Lymanalpha generation. Some important improvements are: (1) efficient collection schemes for Lymenalpha, and (2) implementation of a buildup cavity for 254 nm. With these improvements, we expect to achieve cooling in all three axes on the time scale of minutes. [1] G. Gabrielse et al., Opt. Lett. 43, 2905 (2018). [2] K. S. E. Eikema, J. Walz, and T. W. Hänsch, Phys. Rev. Lett. 86, 5679. [Preview Abstract] 

E01.00153: ManyBody Localized Phase in FewBody Systems S. Gharashi, Abdollah Langari Motivated by recent progress with cold atoms in the field of manybody localization, we investigate the effect of interaction on the localization of atoms in fewbody systems. We consider two cold atoms with shortrange interaction in a onedimensional disordered lattice with finite number of lattice sites. We obtain the exact time evolution of the wave function and monitor the structural properties of the system such as atom imbalance and von Neumann entropy as functions of time. In the limit of vanishing interaction we recover the fewbody version of Anderson localization. Our results confirm that localized phase survives even for finite interaction strength, as we expect for the manybody localized phase. [Preview Abstract] 

E01.00154: Probing spectral and transport properties of atomic FermiHubbard systems Benjamin Spar, Peter Brown, Elmer GuardadoSanchez, Debayan Mitra, Peter Schauss, Waseem Bakr In the past thirty years, there has been much scientific interest in the cuprates, with the discovery of their high temperature superconducting state. The normal states of the doped cuprates are particularly poorly understood, featuring phases with anomalous transport and spectral properties. It is thought that much of the behavior of these materials can be qualitatively described by the FermiHubbard Model, which can be realized with ultracold fermionic atoms in an optical lattice. Using a lithium quantum gas microscope, we are able to probe the dynamic properties necessary to observe the strange metal and pseudogap phases of a FermiHubbard system. First, we perform diffusion measurements in a doped Mott insulator and use the NernstEinstein equation to extract the resistivity. We observe a linearintemperature resistivity, characteristic of a strange metal. Next, we have developed techniques for performing angle resolved photoemission spectroscopy (ARPES) in FermiHubbard systems and used it to study the pseudogap in an attractive Hubbard system. Looking forward, we would like to perform ARPES measurements on the doped repulsive system, which can directly reveal the dwave nature of the pseudogap. [Preview Abstract] 

E01.00155: Probing prethermalization and FloquetBloch dynamics with ultracold lithium in optical lattices Cora Fujiwara, Ethan Simmons, Kevin Singh, Roshan Sajjad, Alec Cao, David Weld Ultracold lithium atoms in optical lattices serve as an adaptable platform for studying time dependent quantum systems. We report on experimental and theoretical characterization of prethermalization in a stronglydriven optical lattice with tunable interactions. We also discuss the creation and study of hybridized FloquetBloch bands using monochromatic and polychromatic driving. [Preview Abstract] 

E01.00156: Investigating the Influence of the Talbot Effect on Novel 2D Atomic Dipole Trap Arrays for Use in Quantum Computing Sergio Aguayo, Katharina GillenChristandl Many configurations of atomic dipole traps have been achieved with interesting applications in molecular, atomic, and biological physics. Our goal is to identify and characterize dipole trap configurations, in particular twodimensional arrays of traps, that could be useful for quantum computing. Candidates are an array of Gaussian beams [1], a projected array of pinholes [2], or a projected array of opaque spots. In this project, we computationally investigate the onset and the influences of the Talbot effect on the trap array formed by passing a laser beam through masks with different arrangements of pinholes. We vary the distance between pinholes, the radius of the pinholes, the number of pinholes, etc. By exploring these options, we hope to make progress towards viable atomic dipole trap arrays which can be used in quantum computers. [1] Piotrowicz et al., Phys. Rev. A 88, 013420 (2013), [2] K. GillenChristandl, et al., Phys. Rev. A 82, 063420 (2010). [Preview Abstract] 

E01.00157: Dynamical Quantum Phase Transitions in Interacting Atomic Interferometers Changyuan Lyu, Qi Zhou Particlewave duality has allowed physicists to establish atomic interferometers as celebrated complements to their optical counterparts in a broad range of quantum devices. However, interactions naturally lead to decoherence. Here, we show that interactions lead to dynamical quantum phase transitions between Schr\"{o}dinger's cat states in an atomic interferometer. These transition points result from zeros of Loschmidt echo, which approach the real axis of the complex time plane in the large particle number limit, and signify pair condensates, another type of exotic quantum states featured with prevailing twobody correlations. Our work suggests interacting atomic interferometers as a new tool for exploring dynamical quantum phase transitions and creating highly entangled states to beat the standard quantum limit. [Preview Abstract] 

E01.00158: Towards tunable atomic interactions in a synthetic lattice of momentum states Shraddha Agrawal, Sai Naga Manoj Paladugu, Eric Meier, Fangzhao Alex An, Bryce Gadway We describe progress towards an updated experimental platform for engineering synthetic lattices based on lasercoupled atomic momentum states. Such systems offer high degrees of local and temporal control over the system parameters of artificial tightbinding models. In our new experiments involving Potassium39 we hope to harness direct control of atomic interactions through a magneticallycontrollable Feshbach resonance. Control over interactions will allow for the systematic exploration of interactiondriven phenomena in tunable synthetic lattices, which can, for example, enable studies of the interplay between interactions and band topology. Furthermore, momentummodedependent interactions will enable the generation of squeezed states of linear momentum, which has promising applications in improved inertial sensing. [Preview Abstract] 

E01.00159: Design and fabrication of a surface trap for trapped ion quantum computing Wending Zhao, Yue Jiang, Zhichao Mao, Quanxin Mei, Zichao Zhou, Li He, Luming Duan In our lab, we focus on constructing scalable micro ion trap systems for quantum computing and simulation. We are building a microfabricated surface trap system which involves trap potential simulation, ion dynamics simulation, the design and fabrication of surface chip trap and other auxiliary setups. We also estimate the heating rate and circuit characters of surface trap experimentally and theoretically. Recently, we finished several versions of surface chip traps which can realize different trap potentials to tune the spacing between the ions. The chip trap was fabricated through the growth of metal coating over a semiconductor substrate with fine structure (\textasciitilde $\mu $m). We also built a segmented blade trap system and work on individual ion addressing and laser frequency stabilization. In the future, we will fabricate more complicated structure on the chip which can give us the capability to transfer quantum information between remote ion traps. [Preview Abstract] 

E01.00160: New density regimes for cold hydroxyl radicals. Alex Aeppli, Hao Wu, Piotr Wcislo, David Reens, Anna McAuliffe, Jun Ye Quantum degenerate polar molecules promise an exciting new twist to the key successes of ultracold atomic physics, as we have already begun to see with ultracold magnetic atoms. We aim to extend these successes to hydroxyl radicals, slowing and trapping them via Stark deceleration, and cooling further by evaporation. This last step requires significantly higher densities than ever achieved previously, for which purpose we are pleased to report several significant gains. [Preview Abstract] 

E01.00161: Carbon adsorption on polycrystalline Au surfaces: Orientation dependence of adsorbed work function/dipole moment Hossein Jooya, X. Fan, Kyle S. McKay, David D.P. Pappass, Dustin A. Hite, Hossein R. Sadeghpour We study how the work function due to carbon adatom adsorption is affected by the crystallographic orientation of the gold surface. \textit{Abinitio} calculations within densityfunctional theory are performed on carbon deposited (100), (110), and (111) gold surfaces. The work function behavior with carbon coverage for the different surface orientations is explained by the resultant electron charge density distributions. Although the carbon adsorption at sub to onemonolayer coverage is dictated by different potential energy landscapes of these surfaces, at much higher coverage, all the three orientations would impose approximately the same work function, associated with the work function of the bulk adsorbate, \textit{i.e.} graphite. This systematic study provides a detailed understanding of deposition on polycrystalline gold electrodes which are used in ion microtraps. [Preview Abstract] 

E01.00162: Ion Confinement and Doppler Laser Cooling in a Permanent Magnet Penning Trap Brian McMahon, Brian Sawyer Largescale Penning traps utilizing electromagnets have proven useful for a variety of trapped chargedparticle experiments including quantum simulation, mass spectrometry, precision metrology, molecular spectroscopy, and measurements of fundamental constants. Unitary Penning traps built with permanent magnets have been demonstrated for storage and spectroscopy of highlycharged ions [1]. Permanentmagnetbased Penning traps allow for passive ion confinement without radiofrequency (RF) micromotion, making them potentially attractive for use in portable frequency references. We will describe recent experimental results including confinement, spectroscopy, and trap characterization using $^{\mathrm{40}}$Ca$^{\mathrm{+}}$ ions in a NdFeBbased combined (RF and Penning) trap operating at 0.6 T. We will also detail progress towards confinement and Doppler cooling of $^{\mathrm{9}}$Be$^{\mathrm{+}}$ in a permanent magnet Penning trap. [1] N.D. Guise, J. N. Tan, S. M. Brewer, C. F. Fischer, and P. Jonsson, Phys. Rev. A \textbf{89}, 040502 (2014) [Preview Abstract] 

E01.00163: Studying lightmatter interaction and energy transfer at nanoscale using a trappedion apparatus WeiTing Chen, Joe Broz, Eli Megidish, Ryan Shaffer, Dylan Gorman, Boerge Hemmerling, Hartmut Haeffner It becomes crucial to understand energy absorption and transfer in structured environments, as people move to the direction of designing nanoscale engineered materials where environments can be tailored to function. However, it is a grand challenge because solving theoretical models for such phenomena, which often occur over vastly different time and energy scales, has proven difficult on classical computers. Thus, our goal is to develop a quantum simulation platform based on precisely controlled trapped ions capable of modeling energy absorption and transfer in complex environments. We expect that the insights from these studies will inform the design of nextgeneration photovoltaic technologies and optoelectronic devices. Here we demonstrated proof of principle experiments using two ions and describe the undergoing progress and future plans. [Preview Abstract] 

E01.00164: Sayma: Agile RF for Coherent Quantum Control Using ARTIQ Joseph W. Britton, David T. C. Allcock, Chris Ballance, Tom P. Harty, Robert Jordens, Greg Kasprowicz, Pawel Kulik, Daniel H. Slichter, Weida Zhang, Sebastien Bourdeauducq The Advanced RealTime Infrastructure for Quantum physics (ARTIQ) [1] is a control system for quantum information experiments. It features a highlevel programming language called ARTIQ Python, in which complex experiments can be expressed. Experiment code is compiled and executed on dedicated FPGA hardware with nanosecond timing resolution and microsecond branching latency. The system was designed to meet the requirements of complex, feedbackbased algorithms including quantum error correction and networking. Sinara [2] is an open source suite of high performance FPGAbased hardware designed for trapped ion qubit systems using ARTIQ. This poster discusses the Sayma high performance DAC system, a Sinara component with high channel density, low phase noise, and phasesynchronous operation. The DACs provide a 16bit output at data rates up to 1 GSPS, with digital interpolation enabling output clock rates up to 2.4 GHz. Output waveforms are defined parametrically, easing waveform storage requirements and enabling lowlatency feedback for waveform frequencies and amplitudes. Clock synchronization follows a scheme similar to CERN's White Rabbit. [1] github.com/mlabs/artiq [2] sinarahw.github.io [Preview Abstract] 

E01.00165: A dualspecies hybrid MOT/Paul trap Tyler Bennett, Sarah Hill, Robert Sprenkle, Scott Bergeson We report on progress to create a hybrid dualspecies calcium and ytterbium magnetooptical trap (MOT) superimposed onto a linear Paul trap. This configuration will allow us to trap neutral atoms in the MOT, ionize them using nsduration pulsed lasers, and then trap the resulting plasma in the Paul trap. By driving the trap at two frequencies we will eliminate centrifugal separation inherent in simultaneous trapping of different mass ions. The primary goal of this experiment is to measure collisional momentum transfer between the Yb$^{\mathrm{+}}$ and Ca$^{\mathrm{+}}$ ions as a means of determining the Coulomb logarithm in a strongly coupled plasma environment. Using carefully aligned probe laser beams and by spatially imaging ion fluorescence, we anticipate being able to distinguish between the coherent ion micromotion and the thermal ion motion in the plasma. [Preview Abstract] 

E01.00166: Detection of Feshbach resonances between Na and Cs atoms Eliot F. Fenton, Jessie Zhang, YenWei Lin, KangKuen Ni Due to its large electric dipole moment and resulting longrange interactions, NaCs is a promising candidate for quantum information experiments. Trapping of other bialkali molecules has relied on the formation of Feshbach molecules, followed by STIRAP to the rovibrational and electronic ground states. Here, we report on detection of Feshbach resonances between sodium and cesium atoms trapped in a single optical tweezer. These results allow for groundstate trapping of NaCs molecules. [Preview Abstract] 

E01.00167: Collisional Dynamics of NaLi Molecules in the Triplet Ground State Juliana Park, Hyungmok Son, Jiangtian Yao, Martin Zwierlein, Alan Jamison, Wolfgang Ketterle Ultracold gases of molecules allow us to study shortrange chemical reactions, novel quantum phases, and quantum information processing. The NaLi molecule, the lightest bialkali molecule, in the triplet ground state has permanent electric and magnetic dipole moments and is predicted to have a small universal loss rate leading to long collisional lifetime. This enables us to investigate the complexity of chemical reactions by finding links to scattering theory. We have previously achieved the longlived triplet ground state molecules in an optical dipole trap through a twostep process: formation of Feshbach molecules and stimulated rapid adiabatic passage. We report results of recent studies with our triplet state molecules including the observation of long lifetime of the molecules in a longer wavelength optical dipole trap and collisional properties of the molecules with sodium atoms. [Preview Abstract] 

E01.00168: Optimized production of NaRb Feshbach molecules Jun Yu Lin, Junyu He, Xin Ye, Dajun Wang The conversion from free atom pairs to weakly bound Feshbach molecules via magnetoassociation is a critical step for the quest toward a quantum degenerate sample of ultracold polar molecules. Although the basic principles for achieving the best conversion efficiency have been laid out a long time ago, the experimentally demonstrated results are typically far from meeting the expectations. In the poster, we will present our recent result in optimizing the production of NaRb Feshbach molecules. By using a larger, colder and less dense mixture of Na BoseEinstein and Rb thermal atoms, we gain a factor of two increase in the absolute number of Feshbach molecules. We also observe a moleculemolecule loss resonance when the binding energy is tuning by the magnetic field. The possibility of magnetoassociation starting from two condensates will also be discussed. [Preview Abstract] 

E01.00169: Laser Cooling of Diatomic Metal Monohydrides for Producing Ultracold Hydrogen Ivan Kozyryev, Rees McNally, Tanya Zelevinsky Despite a tremendous progress in laser technology in recent years, direct laser cooling of the most prevalent atomic species of chemical and biological interest including hydrogen, carbon, oxygen, and nitrogen still remains out of reach. However, many diatomic and polyatomic metalligand radicals can support optical cycling on the metallocalized valence electron, potentially enabling concomitant laser cooling of diverse constituents [1]. We will describe our progress on laser cooling and trapping of barium monohydride (BaH) molecules as a precursor for producing ultracold atomic hydrogen using optical methods. Despite a low recoil velocity (2.7 mm/s) and a relatively slow scattering rate ($10^{6}$ s$^{1}$), we were able to use 1060 nm laser light exciting the $X\rightarrow A$ electronic transition to reduce the transverse velocity spread of the cryogenic buffergas beam of BaH, characterizing the cooling dynamics and benchmarking theoretical estimates. A large atomic mass mismatch between the BaH constituents will be highly beneficial for future kinetic cooling of hydrogen to ultracold temperatures using precision photodissociation of trapped molecules [2]. [1] Kozyryev et al., ChemPhysChem 17, 3641 (2016). [2] I. C. Lane, PRA 92, 022511 (2015). [Preview Abstract] 

E01.00170: Electrostatic trapping of molecules from the cryofuge in a microstructured trap Isabel Rabey, Manuel Koller, Thomas Gantner, Florian Jung, Martin Zeppenfeld, Gerhard Rempe Dense samples of cold polar molecules provide fascinating research possibilities in physics and chemistry. However, densities of cold and slow molecules achieved in past experiments have been insufficient for many applications. In our setup, we solve this problem by combining buffer gas cooling with centrifuge deceleration to create a bright, slow source of molecules, with energies below 1K [1]. The addition of a microstructured electrostatic trap [2] to the end of the \textit{cryofuge} source allows molecules to be trapped and stored for several seconds. Trapped molecules may also be cooled to ultracold temperatures using optoelectrical Sisyphus cooling [3]. The techniques presented here are entirely general and can be applied to a diverse range of molecular species  including lasercoolable molecules. This allows us to investigate a wide variety of topics from cold and ultracold collisions to tests of fundamental physics. \newline [1] X. Wu \textit{et al.}, Science \textbf{358}, 645 (2017) \newline [2] B. G. U. Englert \textit{et al.}, PRL \textbf{107}, 263003 (2011) \newline [3] A. Prehn \textit{et al.}, PRL \textbf{116}, 063005 (2016) [Preview Abstract] 

E01.00171: Quditbased Quantum Computing Protocol with Trapped Barium Ions Pei Jiang Low, Brendan Bramman, Andrew Cox, Matthew Day, Noah Greenberg, Richard Rademacher, Crystal Senko We present a set of protocols for implementing a dlevel qudit quantum computing system with trapped barium ions. The error sources for each procedure in the set of protocols (e.g. single and twoqudit gate implementations) are analyzed indepth with theoretical calculations and numerical simulations. This serves as an estimate of the fundamental limits on the fidelities achievable with our proposed protocol, and provides a practical assessment of the feasibility of realizing a ddimensional quantum computer with trapped ions. [Preview Abstract] 

E01.00172: Quantum jump dynamics in a trapped barium ion Jennifer Lilieholm, Michael Clancy, James Steere, Boris Blinov We are investigating the dynamics of quantum jumps and have set up a system to study them using singly trapped barium ions. Our system is a modified Paul trap containing a parabolic mirror, which allows for light collection from 39\% of the solid angle surrounding the trapped barium ion. This high light collection gives us the ability to quickly detect when a quantum jump occurs. \par Following the work of Minev et al\footnote{Minev, Z. K., et al. "To catch and reverse a quantum jump midflight." arXiv preprint arXiv:1803.00545 (2018).} where they demonstrated the ability to predict quantum jumps in a superconducting artificial atom, we plan to investigate the occurrence of quantum jumps in a single trapped barium ion. [Preview Abstract] 

E01.00173: Nuclear Magnetic Resonance Gyroscope Michael Larsen The Nuclear Magnetic Resonance Gyroscope (NMRG) is being developed by the Northrop Grumman Corporation (NGC). Cold and hot atom interferometer based gyroscopes have suffered from Size, Weight, and Power (SWaP) challenges and limits in bandwidth, scale factor stability, dead time, high rotation rate, vibration, and acceleration. NMRG utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as a reference for determining rotation, providing continuous measurement, high bandwidth, stable scale factor, high rotation rate measurement, and low sensitivity to vibration and acceleration in a low SWaP package. Real time closed loop implementation of the sensor significantly decreases environmental and systematic sensitivities and supports a compact and low power digital signal processing and control system. Therefore, the NMRG technology holds great promise for navigation grade performance in a low cost SWaP package. A new version of the NMRG has been constructed and testing is ongoing. The poster will describe the history, operation, and design of the NMRG. General performance results will also be presented along with recent test results. [Preview Abstract] 

E01.00174: Investigating roaming pathways in photoinduced NO abstraction from nitrobenzene via electron diffraction Kareem Hegazy, Thomas Wolf Roaming mechanisms are thought to be an important unimolecular reaction where molecular fragments ‘roam’ and react or reorganize with the remainder. Roaming has not been directly observed with sufficient time resolution and is considered a possible mechanism for the photoinduced NO dissociation of nitrobenzene. We directly observe the time dependent structural evolution of gas phase nitrobenzene pumped with 266 nm light at the SLAC Ultrafast Electron Diffraction with 0.5 Å and 150 fs spatial and temporal resolution. [Preview Abstract] 

E01.00175: Outofequilibrium dynamics of ultracold bosons in time dependent random potentials Milan Radonji\'c, Axel Pelster We investigate perturbatively the impact of timedependent random potentials on a weakly interacting Bose gas at zero temperature. Generically, a random potential yields, on the ensemble average, a depletion of the condensate. It stems from the localization of bosons in the respective minima of the disordered landscape and is usually quantified by a Boseglass order parameter [1] in close analogy to the wellknown EdwardsAnderson order parameter for spinglasses [2]. A time dependence of the random potential leads in addition to an outofequilibrium dynamics of the condensate depletion.\\ Here we study a smooth quench of a spatially deltacorrelated disordered potential from an initial disorderfree state of a uniform Bose gas. Depending on the quench rise time we focus on two limiting cases: adiabatic and sudden quench. In the longtime limit the former scenario reproduces the static disorder equilibrium case [3], while the latter leads to the formation of a nonequilibrium steady state, which turns out to have an even larger condensate depletion.\\ [1] R. Graham and A. Pelster, Int. J. Bif. Chaos {\bf 19}, 2745 (2009)\\ [2] S. F. Edwards and P. W. Anderson, J. Phys. F {\bf 5}, 965 (1975)\\ [3] K. Huang and H.F. Meng, Phys. Rev. Lett. {\bf 69}, 644 (1992) [Preview Abstract] 

E01.00176: GPMFC Poster Prize Finalists 

E01.00177: Precise Characterization of a Nonuniversal Efimov State and Fewbody Interactions in \textsuperscript{39}K Xin Xie, Michael Van de Graaff, Roman Chapurin, Noah Schlossberger, Jared Popowski, Jose D'Incao, Paul Julienne, Jun Ye, Eric Cornell We perform precise studies of two and threebody interactions near an intermediatestrength Feshbach resonance in \textsuperscript{39}K. We determine, with unprecedented accuracy, the location of the resonance to be $33.5821(13)$ Gauss. Measurement of dimer binding energies, spanning three orders of magnitude, enables the construction of a coupledchannel model for the determination of scattering lengths with low uncertainty. With the derived scattering length map, we discover that this ground Efimov resonance is located at $a_/r_{vdW}=14.19(16)$ ($r_{vdW}$ is the van der Waals length), significantly deviating from the van der Waals universal value $9.73$. A threebody model is introduced to explain the origin of this anomaly. To enrich our understanding of this Efimov spectrum, we extend our study to positive scattering lengths where atomdimer interactions give rise to additional complexities in scattering processes. [Preview Abstract] 

E01.00178: Blochbands Picture and Diffraction Phase Control in Atom Interferometry Katherine E. McAlpine, Daniel Gochnauer, Tahiyat Rahman, Subhadeep Gupta Our ytterbium (Yb), threepath matter wave contrast interferometer (CI) measures the ratio of Planck’s constant and the mass of Yb toward a finestructure constant measurement. The CI uses a BoseEinstein Condensate atom source and pulsed optical standing wave diffraction gratings, using which we have demonstrated phase stable interferometer signals with path separations up to 112 photon recoils [1]. The CI signal is sensitive to intensity fluctuations of acceleration pulses via a momentumdependent AC Stark shift leading to a diffraction phase. We have modeled the system using a Blochbands picture which informs optimal pulse parameters, provides accurate Rabi frequencies for acceleration pulses, and can be used to interferometrically measure lattice band structure. The CI used sequential Bragg pulses to accelerate the atoms to their highest momentum, limited by finite acceleration pulse efficiency. Guided by our model, we are exploring the use of highefficiency excitedband Bloch Oscillation acceleration pulses in a regime of suppressed diffraction phase effects. We will report on our assessment of these different acceleration techniques and their implications for precision contrast atom interferometry. [1] B. PlotkinSwing et al., Phys. Rev. Lett. 121, 133201 (2018). [Preview Abstract] 

E01.00179: The spectrum of the vacuum as a primary reference for radiometry Samuel Lemieux, Enno Giese, Robert Fickler, Maria Chekhova, Robert Boyd The quantummechanical fluctuations of the electromagnetic vacuum exhibit a specific functional dependence on frequency. At the same time, the rate of spontaneous emission of photon crucially depends on their amplitude. In this work, we use the spectrum of vacuum fluctuations to trigger parametric downconversion~(PDC), a nonlinear optical process based on threewave mixing with only one input field. Since we can relate the output of phasematched PDC to the spectrum of the vacuum, PDC qualifies as a reference for the calibration of radiometric instruments. In particular, we deduce the spectral response of a spectrometer using spontaneous PDC\textemdash this is a relative calibration. In the strongcoupling regime of PDC, spontaneous emission stimulates the emission of more photons in a nonlinear manner, leading to a distortion of the frequency spectrum. Since there is a onetoone correspondence between the number of downconverted photons and the spectral shape of highgain PDC, we possess all the necessary knowledge to deduce the spectral quantum efficiency of the spectrometer\textemdash this is an absolute calibration. We experimentally demonstrate that our calibration method compares well against the results obtained with a reference lamp for relative calibration. [Preview Abstract] 

E01.00180: Constraining the axion coupling to timevariation of the electron's electric dipole moment Tanya S. Roussy, William B. Cairncross, Daniel N. Gresh, Matt Grau, Kevin C. Cossel, Yan Zhou, Jun Ye, Eric A. Cornell We have performed a measurement of the electron's permanent electric dipole moment (eEDM) using trapped molecular ions polarized in rotating bias fields. Our initial analysis of the data yielded a mean consistent with zero, assuming no timevariation in the signal. We have performed a more detailed analysis of the data to constrain possible oscillations in the signal over eight orders of magnitude in frequency. This new analysis allows us to constrain the coupling of the hypothetical axion field to the eEDM, which (if present) would generate an oscillatory signal in the eEDM channel. [Preview Abstract] 

E01.00181: Vibrational Molecular Clock in a StateInsensitive Optical Lattice ChihHsi Lee, Stanimir S. Kondov, Kon H. Leung, Christian Liedl, Tanya Zelevinsky Techniques originally developed for atomic clocks can be adapted to ultracold molecules, with applications ranging from quantumstatecontrolled ultracold chemistry to searches for new physics. Here we present recent experimental results with a molecular lattice clock that is based on a frequency difference between two vibrational levels in the electronic ground state of strontium diatomic molecules. Such a clock allows us to test molecular QED, search for massdependent ``fifthforce'' interactions, and potentially probe the electrontoproton mass ratio variations. The achieved quality factor for the molecular clock is $Q=8\times 10^{11}$. Trapinsensitive spectroscopy is crucial for extending coherent moleculelight interactions and achieving high $Q$’s. We have demonstrated a ``magic wavelength'' technique for molecules by manipulating the optical lattice frequency near narrow polarizability resonances. This technique allows us to increase the coherence time by over a thousandfold and to narrow the linewidth of a 30 THz vibrational transition initially to 30 Hz. Long coherence times of molecular state superpositions are critical not only for fundamental metrology but also for quantum information. [Preview Abstract] 

E01.00182: Progress towards Bloch Oscillations of Yb in an optical lattice to search for ultralight dark matter Chandler Schlupf, Robert Niederriter, Paul Hamilton We present the latest developments of an atomic sensor sensitive to oscillating forces. The device consists of ytterbium atoms loaded into an invacuum optical cavity. The atoms undergo Bloch oscillations in the lattice potential driven by an external force such as gravity. Cavity parameters were optimized for efficient atomlight coupling, such that the output light of the cavity is modulated at the Bloch frequency [1]. New fields, such as ultralight dark matter, can create oscillating forces which would be detected through oscillations in the Bloch frequency[2]. This technique allows for continuous measurements in a small volume over a long coherence time. We are currently developing a scheme to cool the Yb atoms into the ground state band of the lattice. \noindent [1] B. Prasanna Venkatesh, M. Trupke, E. A. Hinds, and D. H. J. O'Dell, “Atomic BlochZener oscillations for sensitive force measurements in a cavity", Physical Review A 80, 063834 (2009). \newline [2] A. Arvanitaki, J. Huang, and K. Van Tilburg, ``Searching for dilaton dark matter with atomic clocks", Physical Review D 91, 015015 (2015). [Preview Abstract] 

E01.00183: A cold $^{\mathrm{171}}$Yb trap for atomic EDM measurement Tao Zheng, Yang Yang, Shaobo Zhang, Yukun Feng, Zhaofeng Wan, Shaozheng Wang, Tian Xia, ZhengTian Lu, Matthew Dietrich, Michael Bishof, Peter Mueller, Kevin Bailey, Thomas O'Connor, Roy Ready, Jaideep Singh, BaoLong Lv, ZhuanXian Xiong We present a search for the atomic electric dipole moment (EDM) of $^{\mathrm{171}}$Yb, a stable isotope with the ground state property of L $=$ 0, S $=$ 0, and I $=$ 1/2. $^{\mathrm{171}}$Yb atoms are captured by a twostage MOT, transported using a movable optical dipole trap over 65 cm into a science chamber, and transferred to a 1D optical lattice. There, the atoms are allowed to precess under a uniform B field of 10 mG and a strong, reversible E field of 100 kV/cm. The precession frequencies measured under opposite E fields are used to search for the EDM. We describe the progress, challenges, and prospects of the experiment. Through this experiment, we develop atom manipulation techniques and study systematics for a parallel search for the EDM of $^{\mathrm{225}}$Ra, a radioactive isotope expected to possess a much larger Schiff moment due to its nuclear octupole deformation. [Preview Abstract] 

E01.00184: MAIUSB: Towards dualspecies matterwave interferometry in space Dennis Becker, Maike D. Lachmann, Baptist Piest, Wolfgang Bartosch, Manuel Popp, Thijs Wendrich, 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 and coherent matter wave manipulation in space, we now 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 and will utilize Raman doublediffraction as beam splitters. Here, we give an overview of the planned sounding rocket mission and present the current status of the ongoing groundbased experiments to reach quantum degeneracy of the atomic mixture. We present a groundbased and transportable testbed for the creation of a dual species BEC of Rb87 and K41 in the MAIUSB physics package. The modular design of the laser system allows for independent operation at 780 nm and 767 nm, further enables for grey molasses cooling of potassium, transportation to different testing facilities and easy extension regarding the tests of future experiments like the upcoming ISS multiuser facility BECCAL. [Preview Abstract] 
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