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 K05: Degenerate Fermi Gases and Many-Body PhysicsLive
|
Hide Abstracts |
Chair: Waseem Bakr, Princeton |
Wednesday, June 2, 2021 10:30AM - 10:42AM Live |
K05.00001: Probing the Fermi-Hubbard model through higher-order correlations Annabelle Bohrdt, Yao Wang, Joannis Koepsell, Marton Kanasz-Nagy, Eugene Demler, Fabian Grusdt Conventional solid state experiments typically use momentum-space probes and focus on one and two-point correlation functions. In strongly correlated quantum materials, higher-order correlations can become crucial to fully characterize the many-body system. In particular when comparing different theories, going beyond two-point correlation functions can yield important insights. Quantum simulation, such as quantum gas microscopy of cold atoms in optical lattices, enables the measurement of such higher-order correlations as well as applications of machine learning techniques. In this talk I will discuss recent results on higher-order correlations in the Fermi-Hubbard and t-J model. We identify genuine higher-order correlations between spin and charge which dominate over lower-order terms and explain our findings with a semi-analytical theory. |
Wednesday, June 2, 2021 10:42AM - 10:54AM Live |
K05.00002: Transient Dynamics of a Single Hole in a Fermi-Hubbard Quantum Simulator Martin Lebrat, Geoffrey Ji, Muqing Xu, Lev H Kendrick, Anant Kale, Christie S Chiu, Justus Bruggenjurgen, Daniel Greif, Annabelle Bohrdt, Fabian Grusdt, Eugene Demler, Markus Greiner Understanding the interplay between charge and spin and its effects on transport is a ubiquitous challenge in quantum many-body systems. In the 2D Fermi-Hubbard model, this interplay is thought to give rise to magnetic polarons, whose dynamics may explain emergent properties of quantum materials such as high-temperature superconductivity. Here we use a cold-atom quantum simulator of about 400 sites to directly observe the formation dynamics and subsequent spreading of individual magnetic polarons, by deterministically preparing and releasing single holes in an antiferromagnetic spin background. Site-resolved measurements of the resulting dynamics reveal fast initial delocalization and a dressing of the spin background, indicating polaron formation. At long times we observe dynamics slowed down by the spin exchange time and compatible with a polaronic model with strong density and spin coupling. These results shed light on an iconic yet computationally challenging many-body problem and extend the study of elementary excitations of the Hubbard model far from thermodynamical equilibrium. |
Wednesday, June 2, 2021 10:54AM - 11:06AM Live |
K05.00003: Applying machine learning techniques to ultracold quantum gases Entong ZHAO, Chengdong HE, Elnur Hajiyev, Zejian Ren, Ting Hin Mak, Ka Kwan Pak, Gyu-boong Jo Machine Learning (ML) techniques have emerged as a powerful tool in quantum matter research owing to its ability in analyzing large datasets. Recently, various quantum systems have been explored by applying ML algorithms to data both from numerical simulations and from experiments. In this talk, we demonstrate the benefit of ML technique in quantum gas experiments including the thermodynamic measurement of SU(N) fermions, the detection of topological phase transition out of spin texture, and the thermometry of a Fermi gas. We find that ML-aided analysis efficiently guides us to investigate the useful information and facilitate research in quantum gas systems. Our works complement recent ML studies of quantum many-body physics to explore the underlying physics. |
Wednesday, June 2, 2021 11:06AM - 11:18AM Live |
K05.00004: Spectroscopy of bulk excitations in a supersolid-like Bose-Einstein condensate Sean Mossman, Md Kamrul Hoque Ome, Ethan Crowell, Junpeng Hou, Xiwang Luo, Chuanwei Zhang, Peter W Engels The supersolid state -- a state which is simultaneously superfluid and crystalline -- is a new frontier in the study of quantum states of matter. Speculated to exist in a diverse set of systems stretching from superfluid helium to neutron stars, supersolid-like states have recently been demonstrated with ultracold atoms. In our experiment we prepare a Bose-Einstein condensate (BEC) in a Raman-dressed dispersion which produces a roton mode characteristic of a supersolid state. The application of a weak optical lattice explicitly breaks translational symmetry, coupling to the roton mode and inducing strong crystalline order. In this work we explore the various ways that this implementation allows us to probe the low-energy excitation spectrum of such a state and demonstrate the connection between the explicit symmetry breaking and a gap in the excitation spectrum. This controlled environment for producing a gapped supersolid provides a complementary approach to exploring low-energy supersolid excitations in spontaneous supersolids such as the ones demonstrated in dipolar BECs. |
Wednesday, June 2, 2021 11:18AM - 11:30AM Live |
K05.00005: Dissipative dynamics of quantized vortices in strongly interacting Fermi gases Woo Jin Kwon, Giulia Del Pace, Klejdja Xhani, Luca Galantucci, Alessandro Muzi Falconni, Massimo Inguscio, Francesco Scazza, Giacomo Roati Quantum vortices in a superfluid have fundamental differences compared to classical vortices, especially in their dissipative dynamics due to lack of viscosity. We study the dissipation of quantized vortices in 6Li fermionic superfluids confined in uniform and planar geometry so that a vortex here can be considered as a two-dimensional vortex. To create a vortex and an antivortex, we apply a repulsive obstacle beam focused on the cloud and translate it with a velocity above a critical value. We will first report our measurements on the characteristics of a single dipole across the BEC-BCS crossover. Then, we will show collisional dynamics of a few vortices, which constitutes the fundamentals of many-body vortex dynamics in quantum fluids. Finally, we will address dissipation in vortex collisions, which is inherently different from dissipation in a single dipole case. |
Wednesday, June 2, 2021 11:30AM - 11:42AM Live |
K05.00006: Implementing a Bose-Hubbard model of matter-wave polaritons Youngshin Kim, Joonhyuk Kwon, Alfonso Lanuza, Dominik Schneble Recent experiments on matter-wave emission in a state-dependent optical lattice [1] provide novel features for dressing atoms. Here we present the realization of a Bose-Hubbard model of lattice-trapped atoms that are coherently coupled to the matter-wave vacuum, thus forming a system of quasiparticles with polaritonic character. We explore the many-body properties of these polaritons, including renormalization of hopping and interactions, and observe the quantum phase transition between a superfluid and the Mott insulator. |
Wednesday, June 2, 2021 11:42AM - 11:54AM Live |
K05.00007: Dynamical Phase Diagram of Ultracold Josephson Junctions. Klejdja Xhani, Luca Galantucci, Carlo Barenghi, Giacomo Roati, Andrea Trombettoni, Nikolaos Proukakis In Josephson junctions with ultracold atoms, the Josephson current can be driven by a chemical potential difference across the junction, which can be present due to nonlinear interactions and for a non-zero population imbalance z(t) between the two wells. Depending on the value of the initial imbalance z0 different dynamical regimes could be found. In fact, if z0 is smaller than a critical value zcr the system enters the `plasma' regime. When z0 instead exceeds zcr, different experimental studies observed a transition either to self-trapping (as e.g. Ref.~[1]), or to a dissipative regime (as e.g. Ref.~[2]). These findings raise the interesting question of what distinguishes between such transitions/regimes, and whether a particular experimental set-up could be found that would allow for all three regimes to be observed. |
Wednesday, June 2, 2021 11:54AM - 12:06PM Live |
K05.00008: Topological invariant for gaussian mixed states of fermion systems with time-reversal symmetry Lukas Wawer, Michael Fleischhauer Topological properties of Gaussian mixed states of fermions can be fully classified by the single-particle correlation matrix, which defines the ficticious Hamiltonian |
Wednesday, June 2, 2021 12:06PM - 12:18PM Live |
K05.00009: Vortex dynamics in a rapidly rotating BEC Airlia Shaffer, Cedric Wilson, Parth B Patel, Zhenjie Yan, Biswaroop Mukherjee, Richard Fletcher, Martin W Zwierlein Vortex dynamics play a central role in the physics of fractional quantum Hall materials and superconductors. We study interacting vortices in a rotating BEC under a novel geometric squeezing probe. As the angular momentum of the BEC increases, like-sign vortices cluster due to a hydrodynamic instability. Adding further angular momentum creates charge-flux quasiparticles of vortices attached to BEC clusters. Using high-resolution in situ imaging, we directly observe the quantized edge current associated to these quasiparticles. |
Wednesday, June 2, 2021 12:18PM - 12:30PM On Demand |
K05.00010: Quantum critical dynamics in a spinor Hubbard model quantum simulator Zachary N Shaw Three-dimensional (3D) strongly correlated many-body systems, especially their dynamics across quantum phase transitions, are prohibitively difficult to be numerically simulated. We implement a quantum simulator to study these many-body dynamics using an antiferromagnetic spinor Bose-Einstein condensate confined in a cubic optical lattice. We find dynamics and scaling effects beyond the scope of existing theories at superfluid-insulator quantum phase transitions, and highlight spin populations as a good observable to probe the quantum critical dynamics. Our data indicate that the scaling exponents are independent of the nature of the quantum phase transitions. We also explore the differences between spin population and superfluid order parameter as observables and discuss benefits and deficiencies of each. |
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