Free probability via entropic optimal transport

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Arizmendi, Octavio, Johnston, Samuel G. G.
Format: Preprint
Published: 2023
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866909160625405952
author Arizmendi, Octavio
Johnston, Samuel G. G.
author_facet Arizmendi, Octavio
Johnston, Samuel G. G.
contents Let $μ$ and $ν$ be probability measures on $\mathbb{R}$ with compact support, and let $μ\boxplus ν$ denote their additive free convolution. We show that for $z \in \mathbb{R}$ greater than the sum of essential suprema of $μ$ and $ν$, we have \begin{equation*} \int_{-\infty}^\infty \log(z - x) μ\boxplus ν(\mathrm{d}x) = \sup_Π \left\{ \mathbf{E}_Π[\log(z - (X+Y)] - H(Π|μ\otimes ν) \right\}, \end{equation*} where the supremum is taken over all couplings $Π$ of the probability measures $μ$ and $ν$, and $H(Π|μ\otimes ν)$ denotes the relative entropy of a coupling $Π$ against product measure. We prove similar formulas for the multiplicative free convolution $μ\boxtimes ν$ and the free compression $[μ]_τ$ of probability measures, as well as for multivariate free operations. Thus the integrals of a log-potential against the fundamental measure operations of free probability may be formulated in terms of entropic optimal transport problems. The optimal couplings in these variational descriptions of the free probability operations can be computed explicitly, and from these we can then deduce the standard $R$- and $S$-transform descriptions of additive and multiplicative free convolution. We use our optimal transport formulations to derive new inequalities relating free and classical operations on probability measures, such as the inequality \begin{equation*} \int_{-\infty}^\infty \log(z - x) μ\boxplus ν(\mathrm{d}x) \geq \int_{-\infty}^{\infty} \log(z-x) μ\ast ν( \mathrm{d}x) \end{equation*} relating free and classical convolution. Our approach is based on applying a large deviation principle on the symmetric group to the quadrature formulas of Marcus, Spielman and Srivastava.
format Preprint
id arxiv_https___arxiv_org_abs_2309_12196
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Free probability via entropic optimal transport
Arizmendi, Octavio
Johnston, Samuel G. G.
Probability
Functional Analysis
Operator Algebras
Primary: 46L54, 60F10. Secondary: 22C05, 28C10, 49Q22
Let $μ$ and $ν$ be probability measures on $\mathbb{R}$ with compact support, and let $μ\boxplus ν$ denote their additive free convolution. We show that for $z \in \mathbb{R}$ greater than the sum of essential suprema of $μ$ and $ν$, we have \begin{equation*} \int_{-\infty}^\infty \log(z - x) μ\boxplus ν(\mathrm{d}x) = \sup_Π \left\{ \mathbf{E}_Π[\log(z - (X+Y)] - H(Π|μ\otimes ν) \right\}, \end{equation*} where the supremum is taken over all couplings $Π$ of the probability measures $μ$ and $ν$, and $H(Π|μ\otimes ν)$ denotes the relative entropy of a coupling $Π$ against product measure. We prove similar formulas for the multiplicative free convolution $μ\boxtimes ν$ and the free compression $[μ]_τ$ of probability measures, as well as for multivariate free operations. Thus the integrals of a log-potential against the fundamental measure operations of free probability may be formulated in terms of entropic optimal transport problems. The optimal couplings in these variational descriptions of the free probability operations can be computed explicitly, and from these we can then deduce the standard $R$- and $S$-transform descriptions of additive and multiplicative free convolution. We use our optimal transport formulations to derive new inequalities relating free and classical operations on probability measures, such as the inequality \begin{equation*} \int_{-\infty}^\infty \log(z - x) μ\boxplus ν(\mathrm{d}x) \geq \int_{-\infty}^{\infty} \log(z-x) μ\ast ν( \mathrm{d}x) \end{equation*} relating free and classical convolution. Our approach is based on applying a large deviation principle on the symmetric group to the quadrature formulas of Marcus, Spielman and Srivastava.
title Free probability via entropic optimal transport
topic Probability
Functional Analysis
Operator Algebras
Primary: 46L54, 60F10. Secondary: 22C05, 28C10, 49Q22
url https://arxiv.org/abs/2309.12196