Weak integrability breaking perturbations of integrable models

A quantum integrable system slightly perturbed away from integrability is typically expected to thermalize on timescales of order τ∼λ^{−2}, where λ is the perturbation strength. We here study classes of perturbations that violate this scaling, and exhibit much longer thermalization times τ∼λ^{−2ℓ} w...

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Main Authors: Federica Maria Surace, Olexei Motrunich
Format: Article
Language:English
Published: American Physical Society 2023-10-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.5.043019
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author Federica Maria Surace
Olexei Motrunich
author_facet Federica Maria Surace
Olexei Motrunich
author_sort Federica Maria Surace
collection DOAJ
description A quantum integrable system slightly perturbed away from integrability is typically expected to thermalize on timescales of order τ∼λ^{−2}, where λ is the perturbation strength. We here study classes of perturbations that violate this scaling, and exhibit much longer thermalization times τ∼λ^{−2ℓ} where ℓ>1 is an integer. Systems with these “weak integrability breaking” perturbations have an extensive number of quasiconserved quantities that commute with the perturbed Hamiltonian up to corrections of order λ^{ℓ}. We demonstrate a systematic construction to obtain families of such weak perturbations of a generic integrable model for arbitrary ℓ. We then apply the construction to various models, including the Heisenberg, XXZ, and XYZ chains, the Hubbard model, models of spinless free fermions, and the quantum Ising chain. Our analytical framework explains the previously observed evidence of weak integrability breaking in the Heisenberg and XXZ chains under certain perturbations.
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spelling doaj.art-3aa67f2ecca54adfb43b13e51d473bd82024-04-12T17:34:50ZengAmerican Physical SocietyPhysical Review Research2643-15642023-10-015404301910.1103/PhysRevResearch.5.043019Weak integrability breaking perturbations of integrable modelsFederica Maria SuraceOlexei MotrunichA quantum integrable system slightly perturbed away from integrability is typically expected to thermalize on timescales of order τ∼λ^{−2}, where λ is the perturbation strength. We here study classes of perturbations that violate this scaling, and exhibit much longer thermalization times τ∼λ^{−2ℓ} where ℓ>1 is an integer. Systems with these “weak integrability breaking” perturbations have an extensive number of quasiconserved quantities that commute with the perturbed Hamiltonian up to corrections of order λ^{ℓ}. We demonstrate a systematic construction to obtain families of such weak perturbations of a generic integrable model for arbitrary ℓ. We then apply the construction to various models, including the Heisenberg, XXZ, and XYZ chains, the Hubbard model, models of spinless free fermions, and the quantum Ising chain. Our analytical framework explains the previously observed evidence of weak integrability breaking in the Heisenberg and XXZ chains under certain perturbations.http://doi.org/10.1103/PhysRevResearch.5.043019
spellingShingle Federica Maria Surace
Olexei Motrunich
Weak integrability breaking perturbations of integrable models
Physical Review Research
title Weak integrability breaking perturbations of integrable models
title_full Weak integrability breaking perturbations of integrable models
title_fullStr Weak integrability breaking perturbations of integrable models
title_full_unstemmed Weak integrability breaking perturbations of integrable models
title_short Weak integrability breaking perturbations of integrable models
title_sort weak integrability breaking perturbations of integrable models
url http://doi.org/10.1103/PhysRevResearch.5.043019
work_keys_str_mv AT federicamariasurace weakintegrabilitybreakingperturbationsofintegrablemodels
AT olexeimotrunich weakintegrabilitybreakingperturbationsofintegrablemodels