Kavli Affiliate: Zheng Zhu
| First 5 Authors: Qianqian Chen, Shuai A. Chen, Zheng Zhu, ,
| Summary:
The recent discovery of persistent revivals in the Rydberg-atom quantum
simulator has revealed a weakly ergodicity-breaking mechanism dubbed quantum
many-body scars, which are a set of nonthermal states embedded in otherwise
thermal spectra. Until now, such a mechanism has been mainly studied in
Hermitian systems. Here, we establish the non-Hermitian quantum many-body scars
and systematically characterize their nature from dynamic revivals,
entanglement entropy, physical observables, and energy level statistics.
Notably, we find the non-Hermitian quantum many-body scars exhibit
significantly enhanced coherent revival dynamics when approaching the
exceptional point. The signatures of non-Hermitian scars switch from the
real-energy axis to the imaginary-energy axis after a real-to-complex spectrum
transition driven by increasing non-Hermiticity, where an exceptional point and
a quantum tricritical point emerge simultaneously. We further examine the
stability of non-Hermitian quantum many-body scars against external fields,
reveal the non-Hermitian quantum criticality and eventually set up the whole
phase diagram. The possible connection to the open quantum many-body systems is
also explored. Our findings offer insights for realizing long-lived coherent
states in non-Hermitian many-body systems.
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