Persistent breather and dynamical symmetry in a unitary Fermi gas

Fuente: arXiv
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Main Authors: Sun, Dali, Min, Jing, Yan, Xiangchuan, Wang, Lu, Xie, Xin, Wu, Xizhi, Maki, Jeff, Zhang, Shizhong, Peng, Shi-Guo, Zhan, Mingsheng, Jiang, Kaijun
Format: Preprint
Published: 2024
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author Sun, Dali
Min, Jing
Yan, Xiangchuan
Wang, Lu
Xie, Xin
Wu, Xizhi
Maki, Jeff
Zhang, Shizhong
Peng, Shi-Guo
Zhan, Mingsheng
Jiang, Kaijun
author_facet Sun, Dali
Min, Jing
Yan, Xiangchuan
Wang, Lu
Xie, Xin
Wu, Xizhi
Maki, Jeff
Zhang, Shizhong
Peng, Shi-Guo
Zhan, Mingsheng
Jiang, Kaijun
contents SO(2,1) dynamical symmetry makes a remarkable prediction that the breathing oscillation of a scale invariant quantum gas in an isotropic harmonic trap is isentropic and can persist indefinitely. In 2D, this symmetry is broken due to quantum anomaly in the strongly interacting range, and consequently the lifetime of the breathing mode becomes finite. The persistent breather in a strongly interacting system has so far not been realized. Here we experimentally achieve the long-lived breathing mode in a 3D unitary Fermi gas, which is protected by the SO(2,1) symmetry. The nearly perfect SO(2,1) symmetry is realized by loading the ultracold Fermi gas in an isotropic trap and tuning the interatomic interaction to resonance. The breathing mode oscillates at twice the trapping frequency even for large excitation amplitudes. The ratio of damping rate to oscillation frequency is as small as 0.002, providing an interacting persistent breather. The oscillation frequency and damping rate keep nearly constant for different atomic densities and temperatures, demonstrating the robustness of the SO(2,1) symmetry in 3D. The factors that lead to the residual damping have also been clarified. This work opens the way to study many-body non-equilibrium dynamics related to the dynamical symmetry.
format Preprint
id arxiv_https___arxiv_org_abs_2411_18022
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Persistent breather and dynamical symmetry in a unitary Fermi gas
Sun, Dali
Min, Jing
Yan, Xiangchuan
Wang, Lu
Xie, Xin
Wu, Xizhi
Maki, Jeff
Zhang, Shizhong
Peng, Shi-Guo
Zhan, Mingsheng
Jiang, Kaijun
Quantum Gases
Atomic Physics
SO(2,1) dynamical symmetry makes a remarkable prediction that the breathing oscillation of a scale invariant quantum gas in an isotropic harmonic trap is isentropic and can persist indefinitely. In 2D, this symmetry is broken due to quantum anomaly in the strongly interacting range, and consequently the lifetime of the breathing mode becomes finite. The persistent breather in a strongly interacting system has so far not been realized. Here we experimentally achieve the long-lived breathing mode in a 3D unitary Fermi gas, which is protected by the SO(2,1) symmetry. The nearly perfect SO(2,1) symmetry is realized by loading the ultracold Fermi gas in an isotropic trap and tuning the interatomic interaction to resonance. The breathing mode oscillates at twice the trapping frequency even for large excitation amplitudes. The ratio of damping rate to oscillation frequency is as small as 0.002, providing an interacting persistent breather. The oscillation frequency and damping rate keep nearly constant for different atomic densities and temperatures, demonstrating the robustness of the SO(2,1) symmetry in 3D. The factors that lead to the residual damping have also been clarified. This work opens the way to study many-body non-equilibrium dynamics related to the dynamical symmetry.
title Persistent breather and dynamical symmetry in a unitary Fermi gas
topic Quantum Gases
Atomic Physics
url https://arxiv.org/abs/2411.18022