Bulletin of the American Physical Society
54th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 68, Number 7
Monday–Friday, June 5–9, 2023; Spokane, Washington
Session C08: Quantum Phases in Optical Lattices I |
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Chair: Lindsay LeBlanc, University of Alberta Department of Physics Room: 206 C |
Tuesday, June 6, 2023 10:45AM - 10:57AM |
C08.00001: Out-of-equilibrium dynamics of the two-component Bose-Hubbard model Florian Baer, Malcolm P Kennett Cold atoms in optical lattices can be used as quantum simulators to study the temporal evolution of quantum systems, which has lead to increasing interest in the out-of-equilibrium dynamics of multi-component bosons in optical lattices. We study the Bose Hubbard model for two component bosons using a strong-coupling approach within the closed time path formalism and develop an effective theory for the action of this problem. We obtain equations of motion for the superfluid order parameter and study these in the low-frequency, long wavelength limit during a quantum quench for various initial conditions. |
Tuesday, June 6, 2023 10:57AM - 11:09AM |
C08.00002: Generalized effective spin chain Hamiltonian of strongly interacting spinor gases in optical lattice Sagarika Basak, Han Pu We develop an effective spin-chain model to study strongly interacting spinor gases in a one-dimensional lattice. Previous work (Phys. Rev. A 91, 043634, 2015; Phys. Rev. A 95, 043630, 2017) demonstrated a mapping of a continuum one-dimensional spinor gas with contact s-wave interaction, to the direct product of the wave function of a spinless Fermi gas with short-range p-wave interaction and a spin system governed by spin-parity projection operators. The mapping allowed for a generalized spin-chain model that captures the static and dynamics properties of the system. Here, the extension to lattice systems, provides a computationally efficient tool to study strongly interacting spinor gases in an optical lattice as an alternative to t-J Model and slave particle formalism. It allows us to study gases with arbitrary spin and statistics, providing a universal approach for one-dimensional strongly interacting gases. The spin-chain formalism being simple in its definition, provides an easier tool for study when compared to t-J model and slave particle formalism. Additionally, the extension provides an approach to study them in continuum or in lattice demonstrating the wide applicability of the spin-chain model. The mapped system reproduces the quasi-momentum distributions of SU(n) fermions (Nat. Phys. 10, 198–201, 2014), the ground states of the t-J model, momentum distributions and spin correlations studied for Fermi-Hubbard (Phys. Rev. B 41, 2326, 1990) and Bose-Hubbard Hamiltonian of 1D lattice gases at large on-site interaction. As an application, it also is used to study the dynamics of a quenched system, and the ground state behavior as a function of temperature for strongly-interacting spinor gases in 1D. The spin-chain Hamiltonian is useful in the study of a multitude of interesting phenomena arising in lattice systems such as high-Tc superconductivity, the spin-coherent Luttinger liquid and the spin-incoherent Luttinger liquid regimes. |
Tuesday, June 6, 2023 11:09AM - 11:21AM |
C08.00003: The Effect of Spin-Orbit Coupling on Spin-Polarized Cold Atomic Fermi Systems in Optical Lattices Dhan Bautista, Ettore Vitali, Peter Rosenberg, Shiwei Zhang Evidence of the stability of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase has recently been presented in Phys. Rev. Lett. 128, 203201 (2022), for dense spin-polarized Fermi atomic gases in optical lattices. Building upon these non-perturbative results, we investigate the effect of additional terms in the Hamiltonian to the FFLO phase, namely spin-orbit coupling and in- and out-of-plane Zeeman fields. Such terms can be engineered experimentally in cold atomic Fermi systems and are expected to open the possibility to observe exotic superfluid states with non-trivial topological properties. Preliminary mean-field results from Hartree-Fock-Bogoliubov (HFB) calculations will be discussed to shed light on the different orders that can emerge in the low-energy landscape of cold atomic systems in optical lattices. These HFB calculations may then be later interfaced with correlated Quantum Monte Carlo methodologies. |
Tuesday, June 6, 2023 11:21AM - 11:33AM |
C08.00004: Measuring Talbot revivals with a matter-wave microscope Justus Brüggenjürgen, Mathis Fischer, Nora Bidzinski, Christof Weitenberg Imaging is crucial for gaining insight into physical systems. In the case of ultracold atoms in optical lattices, quantum gas microscopes have revolutionized the access to quantum many-body systems by resolving single lattice sites. However they are limited to investigating 2D systems and are technically demanding. |
Tuesday, June 6, 2023 11:33AM - 11:45AM |
C08.00005: Optical superlattices for quantum gas microscopy of the Fermi-Hubbard model Thomas Chalopin, Dominik Bourgund, Sarah Hirthe, Petar Bojovic, Si Wang, Immanuel Bloch, Timon A Hilker We report on our recent implementation of bichromatic optical superlattices in our 6Li quantum gas microscope. The phase stability and tunability granted by our design provide the necessary tools to implement novel cooling protocols and preparation techniques in tailored geometries. Such superlattice-based protocols open the way to expand our studies of the pairing mechanisms at play in the low energy doped Fermi-Hubbard model. |
Tuesday, June 6, 2023 11:45AM - 11:57AM |
C08.00006: Towards ultracold atoms in a kagome optical lattice with single-site-resolved imaging Luca Donini, Sompob Shanokprasith, Daniel Braund, Tobias Marozsak, Tim Rein, Max Melchner von Dydiowa, Daniel G Reed, Tiffany Harte, Mehedi Hasan, Ulrich Schneider We are building an ultracold-atom setup implementing an optical kagome lattice. This lattice displays strong geometric frustration, which results in a flat band. For fermions, this makes the kagome antiferromagnet a candidate for studying the quantum spin liquid phase. For bosons, frustration has been predicted to e.g. give rise to interaction-driven condensation and a supersolid state. Since the flat band is the highest-lying subband, we plan to access it by creating a negative absolute temperature state. Our experiment is capable of cooling bosonic 87Rb and 39K and fermionic 40K to quantum degeneracy, thus enabling studies of strongly correlated physics in bosons, fermions, and mixtures. |
Tuesday, June 6, 2023 11:57AM - 12:09PM |
C08.00007: Dipolar Quantum Solids in a Quantum Gas Microscope Alexander M Douglas, Lin Su, Michal Szurek, Vassilios Kaxiras, Ognjen Markovic, Markus Greiner We demonstrate dipolar phases of the extended Bose-Hubbard model with an ultracold gas of magnetic Erbium atoms in two dimensions. To create dipolar quantum solids, we adiabatically load a BEC into a small spacing square lattice. When the dipolar interaction becomes dominant we observe a quantum phase transition in which the superfluid order is broken and a solid is formed. We tune the dipole-dipole interactions by rotating the atomic dipole orientation via a bias magnetic field. Depending on this orientation we spontaneously form checkerboard solid or stripe solid phases. We observe these dipolar quantum solids by measuring connected density-density correlation constructed from site-resolved images in our quantum gas microscope. These observations open the gate to site-resolved quantum simulation of lattice models with long-range interactions, such as more exotic phases in the extended Hubbard models like the supersolid phase and the Haldane Insulator phase, as well as dynamics in anisotropic XXZ models. |
Tuesday, June 6, 2023 12:09PM - 12:21PM |
C08.00008: Fermi Gas Microscopy Beyond the Square Lattice Geometry Youqi Gang, Muqing Xu, Lev H Kendrick, Anant Kale, Geoffrey Ji, Martin Lebrat, Markus Greiner Quantum gas microscopy with fermionic atoms provides new insights into the rich quantum phases in the Fermi-Hubbard model. Beyond the standard square lattice, nonstandard band structures are believed to host novel quantum phases, from unconventional superconductors in honeycomb lattices to chiral spin liquids in kagome lattices. Thus, to expand the capability of our quantum gas microscope for studying a broader range of correlated phases, we implemented an optical lattice whose potential can be tuned to realize triangular, honeycomb, and non-bipartite square geometries. This is achieved by actively phase-locking two lattice beams to create an interfering lattice and using a third beam to adjust the lattice depth along one direction. With our tunable lattice, we were able to investigate the magnetic order in an anisotropic triangular lattice as a function of frustration and doping. This tunable lattice can be combined with a digital micromirror device to explore novel quantum phases in decorated lattice geometries. The dynamical tunability also facilitates full spin- and density- resolved imaging, as well as adiabatic state preparation of low entropy strongly correlated quantum phases. |
Tuesday, June 6, 2023 12:21PM - 12:33PM |
C08.00009: Negative absolute temperatures in a triangular optical lattice Mehedi Hasan, Luca Donini, Sompob Shanokprasith, Daniel Braund, Tobias Marozsak, Max Melchner von Dydiowa, Dan Reed, Tiffany Harte, Ulrich Schneider Negative absolute temperatures describe a situation where the entropy of a closed system reduces as the internal energy increases, and this leads to the peculiar situation that atoms in a band dominantly occupy the highest energy states in the band. Here we report the observation of negative absolute temperatures in a triangular optical lattice — a non-bipartite lattice where geometric frustration leads to two inequivalent maxima in the lowest band. This leads to strikingly different critical interaction strengths for the bosonic superfluid to Mott insulator transition at positive and negative absolute temperatures. We furthermore show for both cases how coherence emerges dynamically from a Mott insulator to a superfluid state, reminiscent of the Kibble-Zurek mechanism. |
Tuesday, June 6, 2023 12:33PM - 12:45PM |
C08.00010: Realization of an ultracold indium gas Xianquan Yu, Jinchao Mo, Tiangao Lu, Ting You Tan, Travis L Nicholson Three atom types have been responsible for nearly all the remarkable progress in quantum degenerate gas experiments, namely alkalis, alkaline earths, and dipolar lanthanides. Meanwhile main-group elements III-VIII remain unexplored in the quantum degenerate regime. |
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