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 E07: Frontiers of Atomic Quantum Gases |
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Chair: Bryce Gadway, University of Illinois at Urbana-Champai Room: 206 B |
Tuesday, June 6, 2023 2:00PM - 2:12PM |
E07.00001: Einstein-Podolsky-Rosen experiment with two spatially separated Bose-Einstein condensates Yifan Li, Paolo Colciaghi, Philipp Treutlein, Tilman Zibold In 1935, Einstein, Podolsky, and Rosen (EPR) considered an hypothetical experiment, in which measurements are performed on two spatially separated quantum systems in an entangled state. The entanglement results in strong correlations between the measurement outcomes, making it possible to predict complementary properties of one system based on measurements of the other, with an uncertainty product below the Heisenberg bound. This “EPR paradox” revealed a conflict between quantum mechanics and a local realist description of the world. Since then experiment realisation of the EPR paradox has been realized with small quantum systems, while a demonstration with massive many-particle systems has so far remained elusive. |
Tuesday, June 6, 2023 2:12PM - 2:24PM |
E07.00002: Sound Propagation and Correlation of Quantum Degenerate $^{133}$Cs-$^6$Li Bose-Fermi Mixtures Geyue Cai, Henry Ando, Krutik S Patel, Michael Rautenberg, Sarah McCusker, Cheng Chin We investigate interactions and dynamics of Bose-Einstein condensates(BECs) of $^{133}$Cs atoms immersed in degenerate Fermi gases(DFGs) of $^6$Li atoms. At quantum degeneracy, the interplay between particle-hole excitations of DFGs and phonon excitations of the BECs gives rise to a variety of interesting phenomenon. Based on in-situ imaging and optical potential projection, we excite and image sound propagation in the Bose-Fermi mixtures with tunable interactions across an interspecies Feshbach resonance. Surprisingly, stable sound propagation is observed across the resonance. Furthermore, we develop fast dual species in situ imaging to study correlations of bosonic and fermionic fields in the presence of strong interspecies interactions. |
Tuesday, June 6, 2023 2:24PM - 2:36PM |
E07.00003: Seeing the Forest for the Trees: Connecting Convolutional Neural Networks to Maximum Information Entropy and Correlate Product State Ansatzes Shah Saad Alam, Yilong Ju, Jonathan Minoff, Han Pu, Ankit B Patel, Fabio Anselmi Convolutional Neural Networks(CNNs) are being increasingly used to solve quantum spin systems. Despite their success in doing so, understanding how they succeed and what physics they capture is an ongoing research area. In this talk, we show how CNNs are actually maximum entropy ansatzes (MaxEnt) in disguise. Maximizing information entropy given constraints is the optimal method for constructing a "best guess" probability distribution given little information/constraints, and as such as of great use in physics and statistical mechanics. We show the connection between CNNs and MaxEnts, as well as how they mao onto to another class ofvariational algorithms for spin systems, Entangled Plaquette Correlator Product State Ansatzes (EP-CPS). This allows us to transfer results from existing literature on each ansatz to the gaining understanding of the other. As an example of the mapping, we discuss the case of the spin-1/2 Heisenberg model on a ring. This mapping allows us to use CNNs as a stand-in where Maximum Entropy ansatzes are required, or where EP-CPS ansatzes are being applied in research. |
Tuesday, June 6, 2023 2:36PM - 2:48PM |
E07.00004: Cold Atom Lab: Five Years of Quantum Science on the International Space Station Jason R Williams We present results from the first five operational years of NASA’s Cold Atom Lab (CAL), a versatile multi-user research facility designed to utilize the microgravity environment of the International Space Station to study quantum matter and to serve as a pathfinder for maturing quantum technologies in space. Scientific accomplishments by the original five flight research teams will be highlighted along with near-term plans for enhanced capabilities and research opportunities with CAL to prepare and study quantum gases and mixtures of rubidium-87, potassium-39, and potassium-41at sub-nanokelvin temperatures. We will further report on recently established capabilities for dual-species matter-wave interferometry in space. The impact from this work, and potential for follow-on studies, will be reviewed in the context of future space-based fundamental physics missions. |
Tuesday, June 6, 2023 2:48PM - 3:00PM |
E07.00005: Experimental and theoretical demonstration of quantum degeneracy enhancement in a thermodynamic engine Ethan Q Simmons, Kimberlee Keithley, Roshan Sajjad, Hector Mas, Jeremy Tanlimco, Eber Nolasco-Martinez, Kris T Delaney, Glenn H Fredrickson, David M Weld Thermodynamic engines underpin much of modern technology. Relatively unexplored until recently is the question of whether a quantum mechanical thermodynamic engine can have inherent advantages in efficiency and power over its classical counterpart. As a first step towards answering this question, we experimentally and theoretically characterize an isentropic thermodynamic engine using an interacting quantum-degenerate gas of bosonic $^7$Li as the working fluid. In loose analogy to an Otto cycle, strokes of harmonic trap compression and relaxation are interleaved with strokes of strengthening and weakening contact interactions via a magnetic Feshbach resonance. By subjecting a thermal gas to the same cycle, we observe a quantitative and significant enhancement in both the efficiency and power transfer using the quantum-degenerate working fluid, as well as quantitative agreement with approximation-free interacting simulations. By running this cycle in reverse, we show that the process is isentropic and fully reversible. We characterize the power transfer and cycle efficiencies as a function of trap and interaction compression and cycle time, and show that we achieve high-efficiency, high-power energy transfer between optical and magnetic fields, quantitatively demonstrating quantum degeneracy enhancement of a thermodynamic engine. |
Tuesday, June 6, 2023 3:00PM - 3:12PM |
E07.00006: Learning Physics from Noisy Images of Cold Atoms Michael M Forbes, Kevin R Vixie Noisy absorption images are the primary readout from cold atom experiments. In this talk I will discuss a variety of techniques for solving the inverse problem of learning physics from noisy experimental images. I will introduce techniques like phase retrieval for interferometric imaging, eigenface removal of transients, and various denoising techniques such as total variation regularization (L1-TV) and non-local means. These results derive from a new course, "Learning from Images and Signals" that is part of the iSciMath program at WSU. This program brings together mathematicians and scientists from a variety of fields to solve complex real-world problems at the boundaries of traditional academic domains. |
Tuesday, June 6, 2023 3:12PM - 3:24PM |
E07.00007: Quantum chaos in a harmonic waveguide with scatterers Vladimir Yurovsky An effective method of numerical solution, based on properties of high-rank separable perturbations, is developed for an atom in a harmonic waveguide with either periodic boundary conditions or hard-wall box in the axial direction, perturbed by zero-range scatterers along the waveguide axis [1]. The energy-degeneracy of the unperturbed system can be lifted by an axial vector potential which also lifts T-invariance. The energy spectra properties — near-neighbor distribution and spectral rigidity, as well as the inverse participation ratio (IPR) and fluctuation variance of observable expectation values, are calculated for 106 eigenstates. The chaoticity measures of the model increase with the number of scatterers and their strengths.
The system properties are insensitive to scatterer positions unless the Hamiltonian acquires an additional symmetry, e.g., periodicity [2]. Calculations for different numbers of scatterers and their strengths confirm the prediction [1] that IPR decreases with the number of scatterers. The decrease is inversely proportional for strong scatterers and slower for weak ones. Transition between the T-invariant and T-noninvariant systems and dependencies on the state energy are explored as well. The predictions should be testable experimentally with cold atoms.
1. V. A. Yurovsky, Phys. Rev. Lett. 130, 020404 (2023). 2. V. A. Yurovsky, arxiv/2301.06065.
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