Concentrated Monte Carlo sampling for local observables in quantum spin chains

Fuente: arXiv
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Main Authors: Zhang, Wenxuan, Wang, Dingzu, Poletti, Dario
Format: Preprint
Published: 2025
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author Zhang, Wenxuan
Wang, Dingzu
Poletti, Dario
author_facet Zhang, Wenxuan
Wang, Dingzu
Poletti, Dario
contents Monte Carlo methods are widely used to estimate observables in many-body quantum systems. However, conventional sampling schemes often require a large number of samples to achieve sufficient accuracy. In this work we propose the concentrated Monte Carlo sampling approach, which builds on the idea that in systems with only short range correlations, to obtain accurate expectation values for local observables, one would favor detailed information in the surroundings of this observable compared to far away from it. In this approach we consider all possible configurations in the surroundings of a local observable, and unique samples from the remaining of the setup drawn using Markov chain Monte Carlo. We have tested the performance of this approach for ground states of the spin-1/2 tilted Ising model in different phases, and also for thermal states in the a spin-1 bilinear-biquadratic model. Our results demonstrate that CMCS yields higher accuracy for local observables in short-range correlated states while requiring substantially fewer samples, showcasing in which regimes one can obtain acceleration for the evaluation of expectation values.
format Preprint
id arxiv_https___arxiv_org_abs_2512_05440
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Concentrated Monte Carlo sampling for local observables in quantum spin chains
Zhang, Wenxuan
Wang, Dingzu
Poletti, Dario
Quantum Physics
Statistical Mechanics
Monte Carlo methods are widely used to estimate observables in many-body quantum systems. However, conventional sampling schemes often require a large number of samples to achieve sufficient accuracy. In this work we propose the concentrated Monte Carlo sampling approach, which builds on the idea that in systems with only short range correlations, to obtain accurate expectation values for local observables, one would favor detailed information in the surroundings of this observable compared to far away from it. In this approach we consider all possible configurations in the surroundings of a local observable, and unique samples from the remaining of the setup drawn using Markov chain Monte Carlo. We have tested the performance of this approach for ground states of the spin-1/2 tilted Ising model in different phases, and also for thermal states in the a spin-1 bilinear-biquadratic model. Our results demonstrate that CMCS yields higher accuracy for local observables in short-range correlated states while requiring substantially fewer samples, showcasing in which regimes one can obtain acceleration for the evaluation of expectation values.
title Concentrated Monte Carlo sampling for local observables in quantum spin chains
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2512.05440