Quantum memory at an eigenstate phase transition in a weakly chaotic model

We study a fully connected quantum spin model resonantly coupled to a small environment of non-interacting spins, and investigate how initial state properties are remembered at long times. We find memory of initial state properties, in addition to the total energy, that are not conserved by the dyna...

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Bibliographic Details
Published in:arXiv.org 2022-06
Main Authors: Lambert, M R, Shan-Wen Tsai, Kelly, Shane P
Format: Article
Language:English
Subjects:
Coupling
Eigenvectors
Phase transitions
Quantum phenomena
Thermalization (energy absorption)
Online Access:Get full text
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Summary:We study a fully connected quantum spin model resonantly coupled to a small environment of non-interacting spins, and investigate how initial state properties are remembered at long times. We find memory of initial state properties, in addition to the total energy, that are not conserved by the dynamics. This memory occurs in the middle of the spectrum where an eigenstate quantum phase transition (ESQPT) occurs as a function of energy. The memory effect at that energy in the spectrum is robust to system-environment coupling until the coupling changes the energy of the ESQPT. This work demonstrates the effect of ESQPT memory as independent of integrability and suggests a wider generality of this mechanism for preventing thermalization at ESQPTs.
ISSN:2331-8422
DOI:10.48550/arxiv.2112.07631