Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session M33: Quantum Simulation IIIRecordings Available

Hide Abstracts 
Sponsoring Units: DAMOP Chair: Bharath Hebbe Madhusudhana, LudwigMaximiliansUniversitaet (LMUMunich) Room: McCormick Place W192C 
Wednesday, March 16, 2022 8:00AM  8:12AM 
M33.00001: Opticaldomain spectral superresolution enabled by a quantum memory Mateusz Mazelanik Superresolution methods of optical imaging hold a solid place as an application in biological and chemical sciences, but many new developments allow the beating of diffraction limit in better and more subtle ways by fully exploiting spatial information already present in the optical field. By analogy, full spectral information of the optical field leads to a superresolution spectroscopy, in which we can detect frequency separation of two emitters with precision surpassing the Fourier limit. We employ an optical quantum memory with embedded timefrequency processing capabilities to implement a timeinversion interferometer for input light, thus projecting the optical field in the symmetric–antisymmetric mode basis. This is accomplished by engineering a frequencydependent dispersion combined with timedependent temporal phase modulation that allows us to split, rotate and interfere the signal pulses in the chronocyclic space. Analysis based on quantum metrology shows the advantage of our technique over both conventional spectroscopy as well as heterodyne measurements. Moreover, our work not only establishes a new superresolution spectroscopy method but also provides an exceptionally good spectral resolution, not seen even in Fourier spectrometers. 
Wednesday, March 16, 2022 8:12AM  8:24AM 
M33.00002: Quench dynamics of dipolar BoseHubbard model Kazuhiro Tamura A longrange interaction plays significant roles in Boseparticle systems leading to peculiar phenomena, e.g. spatially ordered structures and droplets in Bosegases[1,2]. Especially in the dipolar BoseHubbard(BH) model, the dipole interaction gives rise to spatially ordered phases, which depends on anisotropy of the interaction [3]. This earlier study also pointed out the existence of an "unstable region" in the phase diagram of the dipolar BH system. In our earlier study, we have shown that in the unstable region, droplets emerge in the dipolar BH system [4]. In Ref. [4], we proposed a toy model that describes the size and shape of droplets. In this presentation, we will show the quench dynamics of the dipolar BH model induced by sudden change of the interaction parameter crossing the phase boundary. We find that the fluctuation of the initial state plays an important role in the relaxation of the system in quench dynamics. We will also discuss the effect of fluctuation on the formation of droplets. 
Wednesday, March 16, 2022 8:24AM  8:36AM 
M33.00003: Using a quantum simulator to benchmark a novel efficient approximation algorithm for localized 1D FermiHubbard systems Bharath Hebbe Madhusudhana, Sebastian Scherg, Thomas Kohlert, Immanuel Bloch, Monika Aidelsburger Identifying and understanding the applications of NISQera quantum simulators and quantum computers is a topical problem. Quantum manybody physics embodies a unique set of problems that are both computationally hard and physically pertinent and are therefore apt for applications of NISQ devices. While stateofthe art neutral atom quantum simulators have made remarkable progress in studying manybody dynamics, they are noisy and limited in the variability of initial state and the observables that can be measured. Here we show that despite these limitations, quantum simulators can be used to develop new numerical techniques to solve for the dynamics of manybody systems in regimes that are practically inaccessible to established numerical techniques [1]. Considering localized 1D FermiHubbard systems, we use an approximation ansatz to develop a new numerical method that facilitates efficient classical simulations in such regimes. Since this new method does not have an error estimate and is not valid in general, we use a neutralatom quantum simulator with L_exp = 290 lattice sites to benchmark its performance in terms of accuracy and convergence for evolution times up to 700 tunnelling times. We then use this method to make a prediction of the behaviour of interacting dynamics for spinimbalanced FermiHubbard systems, which we show to be in quantitative agreement with experimental results. Finally, we demonstrate that the convergence of our method is the slowest when the entanglement depth developed in the manybody system is neither too small nor too large. This represents a promising regime for nearterm applications of quantum simulators. 
Wednesday, March 16, 2022 8:36AM  8:48AM 
M33.00004: Quantum Matter Synthesizer: Seeing and Controlling Individual Atoms Jonathan Trisnadi, Mingjiamei Zhang, Lauren Weiss, Lucas Baralt, Huiting Liu, Samir Rajani, Cheng Chin We present progress on the construction of a "quantum matter synthesizer," a new experimental apparatus that integrates siteresolved imaging of atoms in a submicron lattice with dynamic control using a moveable tweezer array. Cold cesium atoms are first stochastically loaded into a static 2D triangular optical lattice. Subsequently, degenerate Raman sideband cooling is applied to the atoms and the resulting fluorescence is collected on a lownoise CCD to image the site occupancies. A rearrangement algorithm computes tweezer trajectories to bring atoms to a desired configuration. The computed moves are streamed to a digital micromirror device (DMD), which projects the tweezer array with a fast switching speed of 2 kHz. After rearrangement, the atoms are again cooled and their final distribution imaged. We characterize the singlesite imaging fidelity and the DMD tweezer generation. 
Wednesday, March 16, 2022 8:48AM  9:00AM 
M33.00005: Modelling the thermodynamics of ultracold atomic bubbles in space Brendan Rhyno, Nathan Lundblad, Joseph D Murphree, David C Aveline, Courtney Lannert, Smitha Vishveshwara With the recent observation of ultracold atomic bubbles in microgravity using the NASA Cold Atom Lab (CAL) aboard the International Space Station, we discuss modelling the thermodynamic properties of shellshaped quantum fluids and directly compare to the data obtained from the experiment. We calculate the critical temperature required to achieve BoseEinstein condensation (BEC) in the novel hollowedout bubble geometries generated on CAL and, in line with experiment, model how the temperature evolves as an initially condensed gas is inflated into a bubble adiabatically. Using a simplified isotropic `bubbletrap' potential, we show that standard semiclassical methods overestimate the BEC critical temperature for atoms confined in quasi2D thin shells and with this insight carry out our analysis of the anisotropic CAL trap using a hybrid spectral and semiclassical approach. We conclude by discussing the nearfuture possibility of achieving large condensed bubbles on CAL. 
Wednesday, March 16, 2022 9:00AM  9:12AM 
M33.00006: Optimization of PulsedLaser Ablation Production of AlCl for Laser Cooling and Trapping Chen Wang, John R Daniel, Taylor Lewis, Madhav Dhital, ShanWen Tsai, Brian K Kendrick, Chris Bardeen, Boerge Hemmerling Ultracold molecules offer opportunities for many areas of fundamental research, ranging from testing fundamental physics, probing for temporal variations of fundamental constants, quantum simulation of manybody systems, control of chemical reactions and quantum information processing. To realize many of these applications a high phasespace density of ultracold molecules is required. Molecules with highly diagonal FranckCondon factors are particularly wellsuited for this endeavour. Here, we report on our abinitio calculations and our spectroscopy results, which confirm that AlCl has a FranckCondon factor of 99.88%[1], which renders it an excellent candidate for laser cooling and trapping. In addition, we will present our results on optimizing the production of AlCl via laser ablation of various chemical precursors, including AlCl3, Al+KCl, Al+MgCl2, in a cryogenic buffergas beam cell[2] and give an update on our progress towards slowing and cooling AlCl. 
Wednesday, March 16, 2022 9:12AM  9:24AM 
M33.00007: Informationtheoretic description of superconductivity in a doped Mott insulator Caitlin Walsh, Maxime Charlebois, Patrick Sémon, Giovanni Sordi, A.M. S Tremblay Quantum information can be used to advance our understanding of phases of matter in manybody quantum systems. We use tools of quantum information to characterize the entanglementrelated properties of unconventional superconductivity in a doped Mott insulator. We study the twodimensional Hubbard model with cluster dynamical meanfield theory to show how key measures of correlations local entropy, thermodynamic entropy and total mutual information detect the superconducting phase obtained upon doping the Mott insulating phase. We find that the behavior of the difference in the local entropy between the normal and superconducting states follows that of the potential energy. In the superconducting state thermodynamic entropy is strongly suppressed near the Mott insulator, whereas the total mutual information is amplified and shows a peak versus doping. 
Wednesday, March 16, 2022 9:24AM  9:36AM Withdrawn 
M33.00008: Phase diagram of lattice bosons in the presence of cavitymediated and dipolar interactions Jin Yang, Chao Zhang, Barbara CapogrossoSansone Longrange interactions in optical lattices have been extensively studied for more than one decade. Two types of longrange interactions, dipolar interactions and cavitymediated longrange interactions, have been realized in experiments, and the phase diagrams for both systems have been obtained. However, when two types longrange interactions are competing with each other, the phase diagram of the system is still obscure. By means of largescale Monte Carlo simulations, we study the competition between cavitymediated and dipolar interactions in a system of lattice bosons. We also briefly present how to experimentally realize the phases stabilized by the extended BoseHubbard model describing the system. 
Wednesday, March 16, 2022 9:36AM  9:48AM 
M33.00009: Exotic Superfluid Phases in Spin Polarized Systems on Optical Lattices Ettore Vitali, Peter Rosenberg, Shiwei Zhang Leveraging cuttingedge numerical methodologies, we study the ground state of the twodimensional spinpolarized Fermi gas in an optical lattice. We focus on systems at high density and small spin polarization, corresponding to the parameter regime believed to be most favorable to the formation of the elusive FuldeFerrellLarkinOvchinnikov (FFLO) superfluid phase. Our systematic study of large lattice sizes, hosting nearly $500$ atoms, provides strong evidence of the stability of the FFLO state in this regime, as well as a highaccuracy characterization of its properties. Our results for the density correlation function reveal the existence of density order in the system, suggesting the possibility of an intricate coexistence of longrange orders in the ground state. The groundstate properties are seen to differ significantly from the standard meanfield description, providing a compelling avenue for future theoretical and experimental explorations of the interplay between interaction and superfluidity in an exotic phase of matter. 
Wednesday, March 16, 2022 9:48AM  10:00AM 
M33.00010: Two types of BCSBEC crossover of atomic Fermi superfluidin a spherical bubble trap ChihChun Chien, Yan He, Hao Guo Inspired by the spherical bubble traps in microgravity, we derive and analyze the BCSLeggett theory of atomic Fermi superfluid on a thin spherical shell. Despite the flat dispersion within each angular momentum number and jumps between adjacent levels of an ideal Ferm gas on a spherical shell, the properly normalized gap and chemical potential of Fermi superfluid exhibit universal behavior regardless of the planar or spherical geometry. By tuning the attractive interaction, an interactioninduced BCSBEC crossover occurs. However, we consider a different scenario where the particle number and interaction strength are fixed but the sphere is shrinking. The increase of the curvature leads to an increase of the Fermi energy and causes a reduction of the ratio between the pairing and kinetic energies, pushing the system towards the BCS limit. The curvatureinduced BCSBEC crossover is made possible by the compact geometry, exemplified by the spherical bubble traps. The theory paves the way for a systematic study of atomic Fermi superfluid in spherical geometry. 
Wednesday, March 16, 2022 10:00AM  10:12AM 
M33.00011: Superfluidity in the 1D BoseHubbard Model Thomas G Kiely Due to strong quantum fluctuations, superfluidity in one dimension is special: The superfluid state is critical, with powerlawdecaying correlation functions and no BoseEinstein condensation. In a lattice, where one can find an interactiondriven Mott insulator, the physics is even more interesting. We compute the ground state superfluid density of the 1D BoseHubbard model using an infinite variational matrix product state technique. We explore the scaling relationships involving the correlation functions and entanglement entropy, explicitly demonstrating the connection between superfluid density and Luttinger parameters. We compare two different algorithms for optimizing the infinite matrix product state and develop a physical explanation why one of them (VUMPS) is more efficient than the other (iDMRG). 
Wednesday, March 16, 2022 10:12AM  10:24AM 
M33.00012: Entanglement dynamics of bosons in an optical lattice Shion Yamashika, Kota Sugiyama, Ryosuke Yoshii, Daichi Kagamihara, Shunji Tsuchiya Entanglement structure characterizes quantum phases of manybody systems. Recently, entanglement entropy has been measured in a system of bosons in an optical lattice. Motivated by the experiment, we study entanglement dynamics of bosons in an optical lattice based on the BoseHubbard model and investigate how the dynamics of entanglement entropy characterizes the superfluid (SF) and Mott insulating (MI) phases. Specifically, we study quench dynamics from the deep MI regime by numerically calculating the Renyi entropy (RE) using the timeevolving block decimation algorithm. We find that the dynamics of RE exhibits distinct features depending on whether the system is quenched into the SF or the MI phases. When the system is quenched into the SF phase, thermalization occurs and the RE converges to a constant value in time evolution. On the other hand, when the system is quenched into the MI phase, the RE oscillates with a certain period that depends on the strength of the onsite interaction. We develop the effective theory in the strongcoupling regime and obtain an analytic expression for the timeevolution of the RE, which agrees very well with the numerical results. We thus find that the signature of the SFMI phase transition appears in the dynamics of RE. 
Wednesday, March 16, 2022 10:24AM  10:36AM 
M33.00013: Multimagnon quantum manybody scars from tensor operators Long Hin Tang, Nicholas O'Dea, Anushya Chandran We construct a family of threebody spin1/2 Hamiltonians with a superextensive set of infinitely longlived multimagnon states. A magnon in each such state carries either quasimomentum zero or fixed p≠0, and energy Ω. These multimagnon states provide an archetypal example of quantum manybody scars: they are eigenstates at finite energy density that violate the eigenstate thermalization hypothesis, and lead to persistent oscillations in local observables in certain quench experiments. On the technical side, we demonstrate the systematic derivation of scarred Hamiltonians that satisfy a restricted spectrum generating algebra using an operator basis built out of irreducible tensor operators. This operator basis can be constructed for any spin, spatial dimension or continuous nonAbelian symmetry that generates the scarred subspace 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2023 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700