Mutual Multilinearity of Nonequilibrium Network Currents

Fuente: arXiv
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Main Authors: Cengio, Sara Dal, Harunari, Pedro E., Lecomte, Vivien, Polettini, Matteo
Format: Preprint
Published: 2025
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author Cengio, Sara Dal
Harunari, Pedro E.
Lecomte, Vivien
Polettini, Matteo
author_facet Cengio, Sara Dal
Harunari, Pedro E.
Lecomte, Vivien
Polettini, Matteo
contents Continuous-time Markov chains have been successful in modelling systems across numerous fields, with currents being fundamental entities that describe the flows of energy, particles, individuals, chemical species, information, or other quantities. They apply to systems described by agents transitioning between vertices along the edges of a network (at some rate in each direction). It has recently been shown by the authors that, at stationarity, a hidden linearity exists between currents that flow along edges: if one controls the current of a specific "input" edge (by tuning transition rates along it), any other current is a linear-affine function of the input current [PRL 133, 047401 (2024)]. In this paper, we extend this result to the situation where one controls the currents of several edges, and prove that other currents are in linear-affine relation with the input ones. Two proofs with distinct insights are provided: the first relies on Kirchhoff's current law and reduces the input set inductively through graph analysis, while the second utilizes the resolvent approach via a Laplace transform in time. We obtain explicit expressions for the current-to-current susceptibilities, which allow one to map current dependencies through the network. We also verify from our expression that Kirchhoff's current law is recovered as a limiting case of our mutual linearity. Last, we uncover that susceptibilities can be obtained from fluctuations when the reference system is originally at equilibrium.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04298
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mutual Multilinearity of Nonequilibrium Network Currents
Cengio, Sara Dal
Harunari, Pedro E.
Lecomte, Vivien
Polettini, Matteo
Statistical Mechanics
Mathematical Physics
Continuous-time Markov chains have been successful in modelling systems across numerous fields, with currents being fundamental entities that describe the flows of energy, particles, individuals, chemical species, information, or other quantities. They apply to systems described by agents transitioning between vertices along the edges of a network (at some rate in each direction). It has recently been shown by the authors that, at stationarity, a hidden linearity exists between currents that flow along edges: if one controls the current of a specific "input" edge (by tuning transition rates along it), any other current is a linear-affine function of the input current [PRL 133, 047401 (2024)]. In this paper, we extend this result to the situation where one controls the currents of several edges, and prove that other currents are in linear-affine relation with the input ones. Two proofs with distinct insights are provided: the first relies on Kirchhoff's current law and reduces the input set inductively through graph analysis, while the second utilizes the resolvent approach via a Laplace transform in time. We obtain explicit expressions for the current-to-current susceptibilities, which allow one to map current dependencies through the network. We also verify from our expression that Kirchhoff's current law is recovered as a limiting case of our mutual linearity. Last, we uncover that susceptibilities can be obtained from fluctuations when the reference system is originally at equilibrium.
title Mutual Multilinearity of Nonequilibrium Network Currents
topic Statistical Mechanics
Mathematical Physics
url https://arxiv.org/abs/2502.04298