Hidden temperature in the KMP model

Fuente: arXiv
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Main Authors: De Masi, Anna, Ferrari, Pablo A., Gabrielli, Davide
Format: Preprint
Published: 2023
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_version_ 1866929370549977088
author De Masi, Anna
Ferrari, Pablo A.
Gabrielli, Davide
author_facet De Masi, Anna
Ferrari, Pablo A.
Gabrielli, Davide
contents In the Kipnis Marchioro Presutti (KMP) model a positive energy $ζ_i$ is associated with each vertex $i$ of a finite graph with a boundary. When a Poisson clock rings at an edge $ij$ with energies $ζ_i,ζ_j$, those values are substituted by $U(ζ_i+ζ_j)$ and $(1-U)(ζ_i+ζ_j)$, respectively, where $U$ is a uniform random variable in $(0,1)$. A value $T_j\ge 0$ is fixed at each boundary vertex $j$. The dynamics is defined in such way that the resulting Markov process $ζ(t)$, satisfies that $ζ_j(t)$ is exponential with mean $T_j$, for each boundary vertex $j$, for all $t$. We show that the invariant measure is the distribution of a vector $ζ$ with coordinates $ζ_i=T_i X_i$, where $X_i$ are iid exponential$(1)$ random variables, the law of $T$ is the invariant measure for an opinion random averaging/gossip model with the same boundary conditions of $ζ$, and the vectors $X$ and $T$ are independent. The result confirms a conjecture based on the large deviations of the model. When the graph is one-dimensional, we bound the correlations of the invariant measure and perform the hydrostatic limit. We show that the empirical measure of a configuration chosen with the invariant measure converges to the linear interpolation of the boundary values.
format Preprint
id arxiv_https___arxiv_org_abs_2310_01672
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hidden temperature in the KMP model
De Masi, Anna
Ferrari, Pablo A.
Gabrielli, Davide
Probability
Statistical Mechanics
37B15, 37K40, 60C05
In the Kipnis Marchioro Presutti (KMP) model a positive energy $ζ_i$ is associated with each vertex $i$ of a finite graph with a boundary. When a Poisson clock rings at an edge $ij$ with energies $ζ_i,ζ_j$, those values are substituted by $U(ζ_i+ζ_j)$ and $(1-U)(ζ_i+ζ_j)$, respectively, where $U$ is a uniform random variable in $(0,1)$. A value $T_j\ge 0$ is fixed at each boundary vertex $j$. The dynamics is defined in such way that the resulting Markov process $ζ(t)$, satisfies that $ζ_j(t)$ is exponential with mean $T_j$, for each boundary vertex $j$, for all $t$. We show that the invariant measure is the distribution of a vector $ζ$ with coordinates $ζ_i=T_i X_i$, where $X_i$ are iid exponential$(1)$ random variables, the law of $T$ is the invariant measure for an opinion random averaging/gossip model with the same boundary conditions of $ζ$, and the vectors $X$ and $T$ are independent. The result confirms a conjecture based on the large deviations of the model. When the graph is one-dimensional, we bound the correlations of the invariant measure and perform the hydrostatic limit. We show that the empirical measure of a configuration chosen with the invariant measure converges to the linear interpolation of the boundary values.
title Hidden temperature in the KMP model
topic Probability
Statistical Mechanics
37B15, 37K40, 60C05
url https://arxiv.org/abs/2310.01672