Classical simulation of noisy random circuits from exponential decay of correlation

Fuente: arXiv
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Main Authors: Lee, Su-un, Ghosh, Soumik, Oh, Changhun, Noh, Kyungjoo, Fefferman, Bill, Jiang, Liang
Format: Preprint
Published: 2025
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_version_ 1866911197100507136
author Lee, Su-un
Ghosh, Soumik
Oh, Changhun
Noh, Kyungjoo
Fefferman, Bill
Jiang, Liang
author_facet Lee, Su-un
Ghosh, Soumik
Oh, Changhun
Noh, Kyungjoo
Fefferman, Bill
Jiang, Liang
contents We study the classical simulability of noisy random quantum circuits under general noise models. While various classical algorithms for simulating noisy random circuits have been proposed, many of them rely on the anticoncentration property, which can fail when the circuit depth is small or under realistic noise models. We propose a new approach based on the exponential decay of conditional mutual information (CMI), a measure of tripartite correlations. We prove that exponential CMI decay enables a classical algorithm to sample from noisy random circuits -- in polynomial time for one dimension and quasi-polynomial time for higher dimensions -- even when anticoncentration breaks down. To this end, we show that exponential CMI decay makes the circuit depth effectively shallow, and it enables efficient classical simulation for sampling. We further provide extensive numerical evidence that exponential CMI decay is a universal feature of noisy random circuits across a wide range of noise models. Our results establish CMI decay, rather than anticoncentration, as the fundamental criterion for classical simulability, and delineate the boundary of quantum advantage in noisy devices.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06328
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Classical simulation of noisy random circuits from exponential decay of correlation
Lee, Su-un
Ghosh, Soumik
Oh, Changhun
Noh, Kyungjoo
Fefferman, Bill
Jiang, Liang
Quantum Physics
We study the classical simulability of noisy random quantum circuits under general noise models. While various classical algorithms for simulating noisy random circuits have been proposed, many of them rely on the anticoncentration property, which can fail when the circuit depth is small or under realistic noise models. We propose a new approach based on the exponential decay of conditional mutual information (CMI), a measure of tripartite correlations. We prove that exponential CMI decay enables a classical algorithm to sample from noisy random circuits -- in polynomial time for one dimension and quasi-polynomial time for higher dimensions -- even when anticoncentration breaks down. To this end, we show that exponential CMI decay makes the circuit depth effectively shallow, and it enables efficient classical simulation for sampling. We further provide extensive numerical evidence that exponential CMI decay is a universal feature of noisy random circuits across a wide range of noise models. Our results establish CMI decay, rather than anticoncentration, as the fundamental criterion for classical simulability, and delineate the boundary of quantum advantage in noisy devices.
title Classical simulation of noisy random circuits from exponential decay of correlation
topic Quantum Physics
url https://arxiv.org/abs/2510.06328