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arXiv · 1806.11044

Observation of a Transition Between Dynamical Phases in a Quantum Degenerate Fermi Gas

Scott Smale·Peiru He·Ben A. Olsen·Kenneth G. Jackson·Haille Sharum·Stefan Trotzky·Jamir Marino·Ana Maria Rey·Joseph H. Thywissen
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Abstract

A proposed paradigm for out-of-equilibrium quantum systems is that an analogue of quantum phase transitions exists between parameter regimes of qualitatively distinct time-dependent behavior. Here, we present evidence of such a transition between dynamical phases in a cold-atom quantum simulator of the collective Heisenberg model. Our simulator encodes spin in the hyperfine states of ultracold fermionic potassium. Atoms are pinned in a network of single-particle modes, whose spatial extent emulates the long-range interactions of traditional quantum magnets. We find that below a critical interaction strength, magnetization of an initially polarized fermionic gas decays quickly, while above the transition point, the magnetization becomes long-lived, due to an energy gap that protects against dephasing by the inhomogeneous axial field. Our quantum simulation reveals a non-equilibrium transition predicted to exist but not yet directly observed in quenched s-wave superconductors.

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Scott Smale, Peiru He, Ben A. Olsen, Kenneth G. Jackson, Haille Sharum, Stefan Trotzky, Jamir Marino, Ana Maria Rey, Joseph H. Thywissen. 2018-06-28. Observation of a Transition Between Dynamical Phases in a Quantum Degenerate Fermi Gas. https://doi.org/10.1126/sciadv.aax1568

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