Optimal quantum algorithm for Gibbs state preparation

Fuente: arXiv
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Autori principali: Rouzé, Cambyse, França, Daniel Stilck, Alhambra, Álvaro M.
Natura: Preprint
Pubblicazione: 2024
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author Rouzé, Cambyse
França, Daniel Stilck
Alhambra, Álvaro M.
author_facet Rouzé, Cambyse
França, Daniel Stilck
Alhambra, Álvaro M.
contents It is of great interest to understand the thermalization of open quantum many-body systems, and how quantum computers are able to efficiently simulate that process. A recently introduced disispative evolution, inspired by existing models of open system thermalization, has been shown to be efficiently implementable on a quantum computer. Here, we prove that, at high enough temperatures, this evolution reaches the Gibbs state in time scaling logarithmically with system size. The result holds for Hamiltonians that satisfy the Lieb-Robinson bound, such as local Hamiltonians on a lattice, and includes long-range systems. To the best of our knowledge, these are the first results rigorously establishing the rapid mixing property of high-temperature quantum Gibbs samplers, which is known to give the fastest possible speed for thermalization in the many-body setting. We then employ our result to the problem of estimating partition functions at high temperature, showing an improved performance over previous classical and quantum algorithms.
format Preprint
id arxiv_https___arxiv_org_abs_2411_04885
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimal quantum algorithm for Gibbs state preparation
Rouzé, Cambyse
França, Daniel Stilck
Alhambra, Álvaro M.
Quantum Physics
Statistical Mechanics
Mathematical Physics
It is of great interest to understand the thermalization of open quantum many-body systems, and how quantum computers are able to efficiently simulate that process. A recently introduced disispative evolution, inspired by existing models of open system thermalization, has been shown to be efficiently implementable on a quantum computer. Here, we prove that, at high enough temperatures, this evolution reaches the Gibbs state in time scaling logarithmically with system size. The result holds for Hamiltonians that satisfy the Lieb-Robinson bound, such as local Hamiltonians on a lattice, and includes long-range systems. To the best of our knowledge, these are the first results rigorously establishing the rapid mixing property of high-temperature quantum Gibbs samplers, which is known to give the fastest possible speed for thermalization in the many-body setting. We then employ our result to the problem of estimating partition functions at high temperature, showing an improved performance over previous classical and quantum algorithms.
title Optimal quantum algorithm for Gibbs state preparation
topic Quantum Physics
Statistical Mechanics
Mathematical Physics
url https://arxiv.org/abs/2411.04885