Bulletin of the American Physical Society
52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 66, Number 6
Monday–Friday, May 31–June 4 2021; Virtual; Time Zone: Central Daylight Time, USA
Session K06: Quantum Phases in Optical Lattices ILive
|
Hide Abstracts |
Chair: Peter Schauss, Virginia |
Wednesday, June 2, 2021 10:30AM - 10:42AM Live |
K06.00001: Generating and Detecting Topological Phases with Higher Chern Number Abhijeet Alase, David Feder Topological phases with broken time-reversal symmetry and Chern number |C| ≥ 2 are of fundamental interest, but their realization on all experimental platforms, including ultracold atoms in optical lattices, remains challenging. We show that phases with higher Chern number arise when the spin-orbit coupling satisfies a combination of spin and spatial rotation symmetries. We leverage this result both to construct minimal two-band tight binding Hamiltonians that exhibit |C| = 2, 3 phases, and to show that the Chern number of one of the energy bands can be inferred from the particle spin polarization at the high-symmetry crystal momenta in the Brillouin zone. Using these insights, we provide a detailed experimental scheme for the specific realization of a time-reversal-breaking topological phase with |C| = 2 for ultracold atomic gases on a triangular lattice subject to spin-orbit coupling. The Chern number can be directly measured using Zeeman spectroscopy; for fermions the spin amplitudes can be measured directly via time of flight, while for bosons this is preceded by a short Bloch oscillation. Our results provide a pathway to the realization and detection of novel topological phases with higher Chern number in ultracold atomic gases. |
Wednesday, June 2, 2021 10:42AM - 10:54AM Live |
K06.00002: Long Range Ordered Phase in a Quantum Heisenberg Chain with Interactions beyond Nearest Neighbor Sayan Choudhury, Zehan Li, W.Vincent Liu Spin ensembles coupled to optical cavities provide a powerful platform for engineering synthetic quantum matter. Recently, we demonstrated that cavity |
Wednesday, June 2, 2021 10:54AM - 11:06AM Live |
K06.00003: Adiabatic preparation of ultracold lattice bosons across the low-entropy Mott transition Gaétan Hercé, Cécile Carcy, Antoine Tenart, Jan-Philipp Bureik, Alexandre Dareau, David Clément, Tommaso Roscilde The three-dimensional Superfluid-to-Mott transition has been extensively studied with ultracold atoms since its first realization two decades ago [1]. However, the critical regime close to the quantum critical point has hardly been investigated so far. By combining measurements of the 3D momentum-space density ρ(k) of lattice bosons with ab-initio Quantum Monte-Carlo (QMC) calculations of the same quantity [2], we first certify that equilibrium states of the Bose-Hubbard model – including those in the quantum-critical regime above the zero-temperature Mott transition – can be adiabatically prepared (at a constant entropy per particle of S/N = 0.8(1)kB in our experiment) [3]. Upon varying the ratio between the interaction U and the tunnelling energy J across the superfluid transition, we then observe that ρ(k=0) exhibits a sharp transition at a value of U/J consistent with the bulk prediction from quantum Monte Carlo. Finally, the variation of ρ(k=0) with U/J exhibits a critical behavior consistent with the expected 3D XY universality class, showing that the momentum distribution of ultracold bosons can reveal traits of the critical behavior of the superfluid transition even in an inhomogeneous trapped system [4]. |
Wednesday, June 2, 2021 11:06AM - 11:18AM Live |
K06.00004: Quantum droplet phases in multimode optical cavities Petr Karpov, Francesco Piazza Multimode optical cavities is a rapidly developing experimental platform for studying strongly coupled light-matter systems. While in single-mode cavities the interactions are of infinite range and all phase transitions are expected to be of the mean-field type, the multimode cavities feature tunable short- to long-range interactions and give an opportunity for observing transitions where the quantum fluctuations play a significant role. |
Wednesday, June 2, 2021 11:18AM - 11:30AM Live |
K06.00005: Unlimited growth of particle fluctuations in many-body localized phases Maximilian Kiefer-Emmanouilidis, Razmik Unanyan, Michael Fleischhauer, Jesko Sirker A characteristic feature of many-body localization (MBL) is a logarithmic growth of the von Neumann entanglement entropy S after a quantum quench. In lattice systems with particle-number conservation S is the sum of number entropy SN and configurational entropy Sconf . We have recently shown that the logarithmic growth of the entanglement entropy is accompanied by a slow, seemingly unlimited growth of the number entropy, SN ∼lnln t [1]. This violates the standard scenario of MBL, represented by the l-bit Hamiltonian, and raises the question whether the observed behavior is transient or continues to hold at strong disorder in the thermodynamic limit. Here we provide an in-depth numerical study of SN(t) for the disordered Heisenberg chain and find strong evidence that the system is never fully localized even at strong disorder. Calculating the Rényi number entropy SNα(t) for α«1—which is sensitive to large number fluctuations occurring with low probability—we demonstrate that the particle number distribution p(n) in one half of the system has a small but continuously growing tail [2]. |
Wednesday, June 2, 2021 11:30AM - 11:42AM Live |
K06.00006: Strongly Interacting Two-component Coupled Bose Gas in 1D Optical Lattice Sagarika Basak, Han Pu We study one-dimensional strongly interacting two-component bosons in an optical lattice with tunable same-site and nearest neighboring sites intercomponent coupling. Previous work studying two-component Bose–Hubbard model in deep Mott regime without consideration of coupling shows z anti-ferromagnetic and x-y ferromagnetic spin phases in spin-1/2 (New J. Phys. 5 113, 2003) and Mott and x-y ferromagnetic spin phases in spin-1 (Phys. Rev. A 92, 041602(R), 2015). Such a system is experimentally realizable as two component bosons (envisoned as two internal levels of an atom) in a tilted optical lattice. We introduce couplings via nearly resonant microwave field, and the intra-component tunnelings via light-assisted Raman transition. Coupling of the components substantially alters the previously observed spin phases revealing fascinating non-trivial spin correlations. The present consideration of inter-component coupling for unit occupancy gives rise to novel effective ordering of the spins leading to unprecedented spin phases: site-dependent z-x spin configuration with tunable (by hopping parameter) proclivity of spin alignment along z. The examination goes beyond the mean-field approximation by employing exact analysis and Variational Monte Carlo with stochastic minimization on Entangled Plaquette states (EPS). The possibility of the exotic spin phases persisting at occupancy greater than unity and with complex intra-component tunnelings and inter-component coupling are discussed. |
Wednesday, June 2, 2021 11:42AM - 11:54AM Live |
K06.00007: Spin Drude weight of the 1D anisotropic Heisenberg spin-1/2 chain Andrew Urichuk, Jesko Sirker, Andreas Kluemper The 1D anisotropic Heisenberg spin-1/2 chain in the thermodynamic limit is an exactly solvable quantum integrable model. Quantum integrability stems from an infinite number of local conserved charges, resulting in exciting transport properties that are accessible by low-temperature experiments. Our focus is on spin transport, which exhibits a non-zero long-time spin current (the finite spin Drude weight) at critical values of anisotropy with an external magnetic field of zero. This Drude weight exhibits a continuous dependence on the anisotropy at zero temperature, however becomes nowhere continuous at non-zero temperatures. Our goal in this presentation is to convey the current understanding with a focus on the limitations of the thermodynamic Bethe ansatz as applied to the Drude weight calculation. |
Wednesday, June 2, 2021 11:54AM - 12:06PM Live |
K06.00008: Probing p-wave interactions with orbital degrees of freedom in optical lattice systems Mikhail Mamaev, Thomas Bilitewski, Peiru He, Vijin Venu, Joseph H Thywissen, Ana Maria Rey We present a protocol for engineering and observing the many-body dynamics of spin-polarized ultracold fermions interacting via p-wave collisions and loaded in an optical lattice with motion along two dimensions. Our scheme requires a filling of two atoms per site, one in the ground band and another in the subspace of two low-lying excited orbital states. The filled ground band prevents relaxation from the excited bands via Pauli exclusion. A Bragg-type laser coupling is used to dress the orbital states, making their single-particle dispersion highly isotropic. The reduced differential kinetic energy of the dressed states enables p-wave interactions to act collectively and dominate at realistic timescales with a moderate Feshbach enhancement of the scattering volume. In an appropriate parameter regime, we show that the many-body dynamics can be accurately described by a spin model acting on the excited orbitals, and further reduced to a one-axis twisting (OAT) model. We discuss experimentally accessible interferometric protocols to probe the collective OAT dynamics in the orbital degrees of freedom as well as methods of state preparation and measurement using ultracold alkali 40K atoms. |
Wednesday, June 2, 2021 12:06PM - 12:18PM Live |
K06.00009: Collective modes on top of the Gutzwiller approximation in Hubbard models: a novel tool for quantum correlations Fabio Caleffi, Massimo Capone, Alessio Recati, Iacopo Carusotto, Chiara Menotti, Inés de Vega We develop a quantum many-body theory of the Bose-Hubbard (BH) model based on an improved Gutzwiller scheme. Our quantum theory is a generalization of the Bogoliubov theory of weakly-interacting gases and have common features with slave boson techniques. The approach provides accurate results throughout the whole BH phase diagram, from the weakly to the strongly interacting superfluid and across the superfluid-Mott transition [1]. Specifically, we provide (1) a semi-analytical expression for the superfluid stiffness in terms of two-particle correlations between the collective modes of the system and (2) a precise estimation for density fluctuations, for which a quantitative agreement with quantum Monte Carlo data is found. The predictive power of our formalism is shown to include also non-trivial dynamical problems, as the pure dephasing of a two-level impurity in a BH environment [2]. Our description of the BH quantum correlations allows to go beyond the standard spin-boson model and, in particular, to find that the decoherence dynamics is extremely sensitive to the universality class of the superfluid-Mott transition. Finally, we explore exciting perspectives on future applications of our approach, including a recent extension to Fermi-Hubbard systems [3]. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700