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Main Authors: Chen, Zherui, Basso, Joao, Ding, Zhiyan, Lin, Lin
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.07291
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author Chen, Zherui
Basso, Joao
Ding, Zhiyan
Lin, Lin
author_facet Chen, Zherui
Basso, Joao
Ding, Zhiyan
Lin, Lin
contents The presence of energy barriers in the state space of a physical system can lead to exponentially slow convergence for sampling algorithms like Markov chain Monte Carlo (MCMC). In the classical setting, replica exchange (or parallel tempering) is a powerful heuristic to accelerate mixing in these scenarios. In the quantum realm, preparing Gibbs states of Hamiltonians faces a similar challenge, where bottlenecks can dramatically increase the mixing time of quantum dynamical semigroups. In this work, we introduce a quantum analogue of the replica exchange method. We define a Lindbladian on a joint system of two replicas and prove that it can accelerate mixing for a class of Hamiltonians with local energy barriers. We provide a rigorous lower bound on the spectral gap of the combined system's Lindbladian, which leads to an exponential improvement in spectral gap with respect to the barrier height. We showcase the applicability of our method with several examples, including the defected 1D Ising model at arbitrary constant temperature, and defected non-commuting local Hamiltonians at high temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2510_07291
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum Replica Exchange
Chen, Zherui
Basso, Joao
Ding, Zhiyan
Lin, Lin
Quantum Physics
The presence of energy barriers in the state space of a physical system can lead to exponentially slow convergence for sampling algorithms like Markov chain Monte Carlo (MCMC). In the classical setting, replica exchange (or parallel tempering) is a powerful heuristic to accelerate mixing in these scenarios. In the quantum realm, preparing Gibbs states of Hamiltonians faces a similar challenge, where bottlenecks can dramatically increase the mixing time of quantum dynamical semigroups. In this work, we introduce a quantum analogue of the replica exchange method. We define a Lindbladian on a joint system of two replicas and prove that it can accelerate mixing for a class of Hamiltonians with local energy barriers. We provide a rigorous lower bound on the spectral gap of the combined system's Lindbladian, which leads to an exponential improvement in spectral gap with respect to the barrier height. We showcase the applicability of our method with several examples, including the defected 1D Ising model at arbitrary constant temperature, and defected non-commuting local Hamiltonians at high temperature.
title Quantum Replica Exchange
topic Quantum Physics
url https://arxiv.org/abs/2510.07291