Reversibility of Nonequilibrium Dynamics in a Unitary Fermi Gas
Abstract
We theoretically describe and experimentally observe the reversibility of a nonequilibrium state in a unitary Fermi gas confined in a time-dependent trap. Unlike the equilibrium case, reversibility out of equilibrium imposes a stringent condition: the accumulated dynamical phase must be an integer multiple of 2π, i.e., Δϕ= 2ω0 s(T) = 2nπ, where ω0 is the initial trapping frequency and s(T) is the rescaled time after a total evolution time T. We demonstrate the reversibility of an initial nonequilibrium state in an isotropic unitary Fermi gas by driving the optical trap through a round trip. We find two types of reversible pathways, the space-time scaling-invariant and polynomial shortcut-to-adiabaticity (STA) protocols. The phase condition restricts the round-trip time T to discrete values, a distinguishing feature of nonequilibrium dynamics. Our work establishes a clear criterion for the quantum control of nonequilibrium many-body systems beyond linear response and provides practical pathways to reversibility.
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BibTeX
@misc{wu2026reversibility,
title = {{Reversibility of Nonequilibrium Dynamics in a Unitary Fermi Gas}},
author = {Xi-Zhi Wu and Xiangchuan Yan and Xin Xie and Dali Sun and Seong-Ho Shinn and Adolfo del Campo and Kaijun Jiang},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00563},
eprint = {2611.00563},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00563},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Reversibility of Nonequilibrium Dynamics in a Unitary Fermi Gas
AU - Xi-Zhi Wu
AU - Xiangchuan Yan
AU - Xin Xie
AU - Dali Sun
AU - Seong-Ho Shinn
AU - Adolfo del Campo
AU - Kaijun Jiang
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00563
UR - https://arxiv.org/abs/2611.00563
AB - We theoretically describe and experimentally observe the reversibility of a nonequilibrium state in a unitary Fermi gas confined in a time-dependent trap. Unlike the equilibrium case, reversibility out of equilibrium imposes a stringent condition: the accumulated dynamical phase must be an integer multiple of 2π, i.e., Δϕ= 2ω_0 s(T) = 2nπ, where ω_0 is the initial trapping frequency and s(T) is the rescaled time after a total evolution time T. We demonstrate the reversibility of an initial nonequilibrium state in an isotropic unitary Fermi gas by driving the optical trap through a round trip. We find two types of reversible pathways, the space-time scaling-invariant and polynomial shortcut-to-adiabaticity (STA) protocols. The phase condition restricts the round-trip time T to discrete values, a distinguishing feature of nonequilibrium dynamics. Our work establishes a clear criterion for the quantum control of nonequilibrium many-body systems beyond linear response and provides practical pathways to reversibility.
ER -