Integrable dissipative exclusion process: Correlation functions and physical properties

TL;DR

This paper analyzes a generalized exclusion process with creation and annihilation, deriving spectral properties, correlation functions, and current fluctuations, confirming macroscopic fluctuation theory for dissipative systems.

Contribution

It introduces an integrable dissipative exclusion process, computes its spectrum, stationary state, correlation functions, and current fluctuations, linking microscopic models to macroscopic fluctuation theory.

Findings

Spectral gap computed in the thermodynamic limit.

Stationary state expressed via matrix product form.

Exact variance of lattice current matches macroscopic predictions.

Abstract

We study a one-parameter generalization of the symmetric simple exclusion process on a one dimensional lattice. In addition to the usual dynamics (where particles can hop with equal rates to the left or to the right with an exclusion constraint), annihilation and creation of pairs can occur. The system is driven out of equilibrium by two reservoirs at the boundaries. In this setting the model is still integrable: it is related to the open XXZ spin chain through a gauge transformation. This allows us to compute the full spectrum of the Markov matrix using Bethe equations. Then, we derive the spectral gap in the thermodynamical limit. We also show that the stationary state can be expressed in a matrix product form permitting to compute the multi-points correlation functions as well as the mean value of the lattice current and of the creation-annihilation current. Finally the variance of the lattice current is exactly computed for a finite size system. In the thermodynamical limit, it matches perfectly the value obtained from the associated macroscopic fluctuation theory. It provides a confirmation of the macroscopic fluctuation theory for dissipative system from a microscopic point of view.