Discrete generative diffusion models without stochastic differential equations: a tensor network approach

Fuente: arXiv
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Main Authors: Causer, Luke, Rotskoff, Grant M., Garrahan, Juan P.
Format: Preprint
Published: 2024
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author Causer, Luke
Rotskoff, Grant M.
Garrahan, Juan P.
author_facet Causer, Luke
Rotskoff, Grant M.
Garrahan, Juan P.
contents Diffusion models (DMs) are a class of generative machine learning methods that sample a target distribution by transforming samples of a trivial (often Gaussian) distribution using a learned stochastic differential equation. In standard DMs, this is done by learning a ``score function'' that reverses the effect of adding diffusive noise to the distribution of interest. Here we consider the generalisation of DMs to lattice systems with discrete degrees of freedom, and where noise is added via Markov chain jump dynamics. We show how to use tensor networks (TNs) to efficiently define and sample such ``discrete diffusion models'' (DDMs) without explicitly having to solve a stochastic differential equation. We show the following: (i) by parametrising the data and evolution operators as TNs, the denoising dynamics can be represented exactly; (ii) the auto-regressive nature of TNs allows to generate samples efficiently and without bias; (iii) for sampling Boltzmann-like distributions, TNs allow to construct an efficient learning scheme that integrates well with Monte Carlo. We illustrate this approach to study the equilibrium of two models with non-trivial thermodynamics, the $d=1$ constrained Fredkin chain and the $d=2$ Ising model.
format Preprint
id arxiv_https___arxiv_org_abs_2407_11133
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Discrete generative diffusion models without stochastic differential equations: a tensor network approach
Causer, Luke
Rotskoff, Grant M.
Garrahan, Juan P.
Statistical Mechanics
Disordered Systems and Neural Networks
Machine Learning
Diffusion models (DMs) are a class of generative machine learning methods that sample a target distribution by transforming samples of a trivial (often Gaussian) distribution using a learned stochastic differential equation. In standard DMs, this is done by learning a ``score function'' that reverses the effect of adding diffusive noise to the distribution of interest. Here we consider the generalisation of DMs to lattice systems with discrete degrees of freedom, and where noise is added via Markov chain jump dynamics. We show how to use tensor networks (TNs) to efficiently define and sample such ``discrete diffusion models'' (DDMs) without explicitly having to solve a stochastic differential equation. We show the following: (i) by parametrising the data and evolution operators as TNs, the denoising dynamics can be represented exactly; (ii) the auto-regressive nature of TNs allows to generate samples efficiently and without bias; (iii) for sampling Boltzmann-like distributions, TNs allow to construct an efficient learning scheme that integrates well with Monte Carlo. We illustrate this approach to study the equilibrium of two models with non-trivial thermodynamics, the $d=1$ constrained Fredkin chain and the $d=2$ Ising model.
title Discrete generative diffusion models without stochastic differential equations: a tensor network approach
topic Statistical Mechanics
Disordered Systems and Neural Networks
Machine Learning
url https://arxiv.org/abs/2407.11133