Reducing dynamical fluctuations and enforcing self-averaging by opening many-body quantum systems

Fuente: arXiv
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Hauptverfasser: Vallejo-Fabila, Isaias, Kumar-Das, Adway, Zarate-Herrada, David A., Matsoukas-Roubeas, Apollonas S., Torres-Herrera, E. Jonathan, Santos, Lea F.
Format: Preprint
Veröffentlicht: 2024
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author Vallejo-Fabila, Isaias
Kumar-Das, Adway
Zarate-Herrada, David A.
Matsoukas-Roubeas, Apollonas S.
Torres-Herrera, E. Jonathan
Santos, Lea F.
author_facet Vallejo-Fabila, Isaias
Kumar-Das, Adway
Zarate-Herrada, David A.
Matsoukas-Roubeas, Apollonas S.
Torres-Herrera, E. Jonathan
Santos, Lea F.
contents We investigate how the dynamical fluctuations of many-body quantum systems out of equilibrium can be mitigated when they are opened to a dephasing environment. We consider the survival probability (spectral form factor with a filter) evolving under different kinds of random matrices and under a spin-1/2 model with weak and strong disorder. In isolated many-body quantum systems, the survival probability is non-self-averaging at any timescale, that is, the relative variance of its fluctuations does not decrease with system size. By opening the system, we find that the fluctuations are always reduced, but self-averaging can only be ensured away from critical points. Self-averaging is achieved for the long-time dynamics of full random matrices, power-law banded random matrices deep in the delocalized phase, and the Rosenzweig-Porter ensemble in all the phases except at the delocalization-localization transition point. For the spin model, the survival probability becomes self-averaging only in the chaotic regime provided the initial states are in the middle of the spectrum. Overall, a strongly non-self-averaging survival probability in open systems is an indicator of criticality.
format Preprint
id arxiv_https___arxiv_org_abs_2406_14647
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Reducing dynamical fluctuations and enforcing self-averaging by opening many-body quantum systems
Vallejo-Fabila, Isaias
Kumar-Das, Adway
Zarate-Herrada, David A.
Matsoukas-Roubeas, Apollonas S.
Torres-Herrera, E. Jonathan
Santos, Lea F.
Strongly Correlated Electrons
We investigate how the dynamical fluctuations of many-body quantum systems out of equilibrium can be mitigated when they are opened to a dephasing environment. We consider the survival probability (spectral form factor with a filter) evolving under different kinds of random matrices and under a spin-1/2 model with weak and strong disorder. In isolated many-body quantum systems, the survival probability is non-self-averaging at any timescale, that is, the relative variance of its fluctuations does not decrease with system size. By opening the system, we find that the fluctuations are always reduced, but self-averaging can only be ensured away from critical points. Self-averaging is achieved for the long-time dynamics of full random matrices, power-law banded random matrices deep in the delocalized phase, and the Rosenzweig-Porter ensemble in all the phases except at the delocalization-localization transition point. For the spin model, the survival probability becomes self-averaging only in the chaotic regime provided the initial states are in the middle of the spectrum. Overall, a strongly non-self-averaging survival probability in open systems is an indicator of criticality.
title Reducing dynamical fluctuations and enforcing self-averaging by opening many-body quantum systems
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2406.14647