Robust effective ground state in a nonintegrable Floquet quantum circuit

Fuente: arXiv
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Main Authors: Ikeda, Tatsuhiko N., Sugiura, Sho, Polkovnikov, Anatoli
Format: Preprint
Published: 2023
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author Ikeda, Tatsuhiko N.
Sugiura, Sho
Polkovnikov, Anatoli
author_facet Ikeda, Tatsuhiko N.
Sugiura, Sho
Polkovnikov, Anatoli
contents An external periodic (Floquet) drive is believed to bring any initial state to the featureless infinite temperature state in generic nonintegrable isolated quantum many-body systems in the thermodynamic limit, irrespective of the driving frequency $Ω$. However, numerical or analytical evidence either proving or disproving this hypothesis is very limited and the issue has remained unsettled. Here, we study the initial state dependence of Floquet heating in a nonintegrable kicked Ising chain of length up to $L=30$ with an efficient quantum circuit simulator, showing a possible counterexample: The ground state of the effective Floquet Hamiltonian is exceptionally robust against heating, and could stay at finite energy density even after infinitely many Floquet cycles, if the driving period is shorter than a threshold value. This sharp energy localization transition/crossover does not happen for generic excited states. The exceptional robustness of the ground state is interpreted by (i) its isolation in the energy spectrum and (ii) the fact that those states with $L$-independent $\hbarΩ$ energy above the ground state energy of any generic local Hamiltonian, like the approximate Floquet Hamiltonian, are atypical and viewed as a collection of noninteracting quasipartiles. Our finding paves the way for engineering Floquet protocols with finite driving periods realizing long-lived, or possibly even perpetual, Floquet phases by initial state design.
format Preprint
id arxiv_https___arxiv_org_abs_2311_16217
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Robust effective ground state in a nonintegrable Floquet quantum circuit
Ikeda, Tatsuhiko N.
Sugiura, Sho
Polkovnikov, Anatoli
Quantum Physics
Mesoscale and Nanoscale Physics
Quantum Gases
Statistical Mechanics
Strongly Correlated Electrons
An external periodic (Floquet) drive is believed to bring any initial state to the featureless infinite temperature state in generic nonintegrable isolated quantum many-body systems in the thermodynamic limit, irrespective of the driving frequency $Ω$. However, numerical or analytical evidence either proving or disproving this hypothesis is very limited and the issue has remained unsettled. Here, we study the initial state dependence of Floquet heating in a nonintegrable kicked Ising chain of length up to $L=30$ with an efficient quantum circuit simulator, showing a possible counterexample: The ground state of the effective Floquet Hamiltonian is exceptionally robust against heating, and could stay at finite energy density even after infinitely many Floquet cycles, if the driving period is shorter than a threshold value. This sharp energy localization transition/crossover does not happen for generic excited states. The exceptional robustness of the ground state is interpreted by (i) its isolation in the energy spectrum and (ii) the fact that those states with $L$-independent $\hbarΩ$ energy above the ground state energy of any generic local Hamiltonian, like the approximate Floquet Hamiltonian, are atypical and viewed as a collection of noninteracting quasipartiles. Our finding paves the way for engineering Floquet protocols with finite driving periods realizing long-lived, or possibly even perpetual, Floquet phases by initial state design.
title Robust effective ground state in a nonintegrable Floquet quantum circuit
topic Quantum Physics
Mesoscale and Nanoscale Physics
Quantum Gases
Statistical Mechanics
Strongly Correlated Electrons
url https://arxiv.org/abs/2311.16217