Cluster-factorized steady states in finite range processes

TL;DR

This paper introduces a class of finite range processes on a ring where particle hopping rates depend on neighboring sites, generalizing zero-range processes, and provides exact solutions for steady states and correlations.

Contribution

The paper demonstrates that under certain conditions, the steady state of finite range processes can be expressed as a product of cluster-weight functions, extending the factorized steady state concept.

Findings

Steady state can be expressed as a product of cluster-weight functions for certain hop rates.

Finite dimensional transfer-matrix formulation allows exact calculation of correlations.

Identifies conditions for condensation transition in finite range processes.

Abstract

We study a class of nonequilibrium lattice models on a ring where particles hop in a particular direction, from a site to one of its (say, right) nearest neighbours, with a rate that depends on the occupation of all the neighbouring sites within a range R. This finite range process (FRP) for R=0 reduces to the well known zero-range process (ZRP), giving rise to a factorized steady state (FSS) for any arbitrary hop rate. We show that, provided the hop rates satisfy a specific condition, the steady state of FRP can be written as a product of cluster-weight function of (R+1) occupation variables. We show that, for a large class of cluster-weight functions, the cluster-factorized steady state admits a finite dimensional transfer-matrix formulation, which helps in calculating the spatial correlation functions and subsystem mass distributions exactly. We also discuss a criterion for which the FRP undergoes a condensation transition.