Sampling from the Continuous Random Energy Model in Total Variation Distance

Fuente: arXiv
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Main Authors: Lee, Holden, Wu, Qiang
Format: Preprint
Published: 2024
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author Lee, Holden
Wu, Qiang
author_facet Lee, Holden
Wu, Qiang
contents The continuous random energy model (CREM) is a toy model of spin glasses on $\{0,1\}^N$ that, in the limit, exhibits an infinitely hierarchical correlation structure. We give two polynomial-time algorithms to approximately sample from the Gibbs distribution of the CREM in the high-temperature regime $β<β_{\min}:=\min\{β_c,β_G\}$, based on a Markov chain and a sequential sampler. The running time depends algebraically on the desired TV distance and failure probability and exponentially in $(1/g)^{O(1)}$, where $g$ is the gap to a certain inverse temperature threshold $β_{\min}$; this contrasts with previous results which only attain $o(N)$ accuracy in KL divergence. If the covariance function $A$ of the CREM is concave, the algorithms work up to the critical threshold $β_c$, which is the static phase transition point; while for $A$ non-concave, if $β_G<β_c$, the algorithms work up to the known algorithmic threshold $β_G$ proposed in Addario-Berry and Maillard (2020) for non-trivial sampling guarantees. Our result depends on quantitative bounds for the fluctuation of the partition function and a new contiguity result of the ``tilted" CREM obtained from sampling, which is of independent interest. We also show that the spectral gap is exponentially small with high probability, suggesting that the algebraic dependence is unavoidable with a Markov chain approach.
format Preprint
id arxiv_https___arxiv_org_abs_2407_00868
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Sampling from the Continuous Random Energy Model in Total Variation Distance
Lee, Holden
Wu, Qiang
Probability
Disordered Systems and Neural Networks
Data Structures and Algorithms
Mathematical Physics
The continuous random energy model (CREM) is a toy model of spin glasses on $\{0,1\}^N$ that, in the limit, exhibits an infinitely hierarchical correlation structure. We give two polynomial-time algorithms to approximately sample from the Gibbs distribution of the CREM in the high-temperature regime $β<β_{\min}:=\min\{β_c,β_G\}$, based on a Markov chain and a sequential sampler. The running time depends algebraically on the desired TV distance and failure probability and exponentially in $(1/g)^{O(1)}$, where $g$ is the gap to a certain inverse temperature threshold $β_{\min}$; this contrasts with previous results which only attain $o(N)$ accuracy in KL divergence. If the covariance function $A$ of the CREM is concave, the algorithms work up to the critical threshold $β_c$, which is the static phase transition point; while for $A$ non-concave, if $β_G<β_c$, the algorithms work up to the known algorithmic threshold $β_G$ proposed in Addario-Berry and Maillard (2020) for non-trivial sampling guarantees. Our result depends on quantitative bounds for the fluctuation of the partition function and a new contiguity result of the ``tilted" CREM obtained from sampling, which is of independent interest. We also show that the spectral gap is exponentially small with high probability, suggesting that the algebraic dependence is unavoidable with a Markov chain approach.
title Sampling from the Continuous Random Energy Model in Total Variation Distance
topic Probability
Disordered Systems and Neural Networks
Data Structures and Algorithms
Mathematical Physics
url https://arxiv.org/abs/2407.00868