Universal cumulants of the current in diffusive systems on a ring

TL;DR

This paper derives exact first cumulants of current and activity in the symmetric simple exclusion process on a ring, revealing universal large deviation scaling functions applicable to both quantities.

Contribution

It provides the first exact calculations of cumulants for current and activity in SSEP, demonstrating their universal scaling behavior in large systems.

Findings

Large deviation functions exhibit universal scaling form

Same scaling function applies to current and activity

Results derived via Bethe ansatz and fluctuating hydrodynamics

Abstract

We calculate exactly the first cumulants of the integrated current and of the activity (which is the total number of changes of configurations) of the symmetric simple exclusion process (SSEP) on a ring with periodic boundary conditions. Our results indicate that for large system sizes the large deviation functions of the current and of the activity take a universal scaling form, with the same scaling function for both quantities. This scaling function can be understood either by an analysis of Bethe ansatz equations or in terms of a theory based on fluctuating hydrodynamics or on the macroscopic fluctuation theory of Bertini, De Sole, Gabrielli, Jona-Lasinio and Landim.