Slow Relaxation in a Glassy Quantum Circuit

Fuente: arXiv
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Autori principali: Barney, Richard D., Liao, Yunxiang, Galitski, Victor
Natura: Preprint
Pubblicazione: 2024
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author Barney, Richard D.
Liao, Yunxiang
Galitski, Victor
author_facet Barney, Richard D.
Liao, Yunxiang
Galitski, Victor
contents Quantum circuits have become a powerful tool in the study of many-body quantum physics, providing insights into both fast-thermalizing chaotic and non-thermalizing integrable many-body dynamics. In this work, we explore a distinct intermediate class - glassy quantum systems - where thermalization occurs, but over very long timescales. We introduce and analyze a Floquet random quantum circuit that can be tuned between glassy and fully ergodic behavior through a single adjustable parameter. This circuit can be understood as the unitary analog of the block Rosenzweig-Porter model, which is defined by a Hamiltonian. Using an effective field theory for random quantum circuits, we analyze the correlations between quasienergy eigenstates and thereby determine the time evolution of the disorder-averaged density matrix. In the intermediate regime the circuit displays a two-step thermalization process: an initial relaxation within weakly coupled sectors followed by a later, global thermalization. We also show that the ramp of the spectral form factor is enhanced by a factor of the number of sectors in the glassy regime, and at early times in the intermediate regime. These results indicate that quantum circuits provide an ideal platform for the exploration of nontrivial thermalization dynamics in many-body quantum systems, offering deeper insights into quantum thermalization.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23281
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Slow Relaxation in a Glassy Quantum Circuit
Barney, Richard D.
Liao, Yunxiang
Galitski, Victor
Disordered Systems and Neural Networks
Statistical Mechanics
Quantum Physics
Quantum circuits have become a powerful tool in the study of many-body quantum physics, providing insights into both fast-thermalizing chaotic and non-thermalizing integrable many-body dynamics. In this work, we explore a distinct intermediate class - glassy quantum systems - where thermalization occurs, but over very long timescales. We introduce and analyze a Floquet random quantum circuit that can be tuned between glassy and fully ergodic behavior through a single adjustable parameter. This circuit can be understood as the unitary analog of the block Rosenzweig-Porter model, which is defined by a Hamiltonian. Using an effective field theory for random quantum circuits, we analyze the correlations between quasienergy eigenstates and thereby determine the time evolution of the disorder-averaged density matrix. In the intermediate regime the circuit displays a two-step thermalization process: an initial relaxation within weakly coupled sectors followed by a later, global thermalization. We also show that the ramp of the spectral form factor is enhanced by a factor of the number of sectors in the glassy regime, and at early times in the intermediate regime. These results indicate that quantum circuits provide an ideal platform for the exploration of nontrivial thermalization dynamics in many-body quantum systems, offering deeper insights into quantum thermalization.
title Slow Relaxation in a Glassy Quantum Circuit
topic Disordered Systems and Neural Networks
Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2410.23281