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Collective Excitations and Nonequilibrium Phase Transition in Dissipative Fermionic Superfluids
Kazuki Yamamoto1, Masaya Nakagawa2, Naoto Tsuji2,3
1Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
Physical Review Letters
|August 16, 2021
Summary
We predict a new mechanism for inducing collective excitations and a nonequilibrium phase transition in fermionic superfluids by introducing two-body loss. This phenomenon, driven by dissipation, leads to unique dynamics and can be observed in ultracold atomic systems.
Area of Science:
- Quantum physics
- Condensed matter physics
- Ultracold atomic gases
Background:
- Fermionic superfluids exhibit complex quantum phenomena.
- Understanding nonequilibrium dynamics is crucial for quantum many-body systems.
- Dissipation's role in quantum phase transitions is an active research area.
Purpose of the Study:
- To predict a novel mechanism for inducing collective excitations and phase transitions in fermionic superfluids.
- To investigate the effects of two-body loss (dissipation) on superfluid properties.
- To explore the realization of these phenomena in ultracold atomic systems.
Main Methods:
- Extension of the Bardeen-Cooper-Schrieffer (BCS) theory to include particle number changes.
- Theoretical modeling of fermionic superfluids coupled via a Josephson junction.
- Analysis of superfluid order parameter dynamics under sudden dissipation.
Main Results:
- A new mechanism for inducing collective excitations and a nonequilibrium phase transition via two-body loss is predicted.
- Sudden dissipation leads to amplitude oscillations and chirped phase rotation of the superfluid order parameter.
- Dissipation in a Josephson junction induces a dynamical phase transition, evidenced by vanishing dc Josephson current.
Conclusions:
- Two-body loss provides a novel pathway to control and induce nonequilibrium phenomena in fermionic superfluids.
- The predicted effects, including collective modes and phase transitions, are experimentally accessible with ultracold fermionic atoms.
- This work offers insights into dissipation-driven quantum dynamics and phase transitions in many-body systems.
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