Comment on "Generalized exclusion processes: Transport coefficients"

TL;DR

This paper critiques a recent study on generalized exclusion processes, emphasizing that correlations affect diffusion even in the hydrodynamic limit and linking the results to prior work.

Contribution

It clarifies the role of correlations in diffusion and connects the derived expressions to earlier established results.

Findings

Correlations influence diffusion in the hydrodynamic limit.

The derived expressions are special cases of earlier results.

Highlights the importance of considering correlations in transport models.

Abstract

In a recent paper Arita et al. [Phys. Rev. E 90, 052108 (2014)] consider the transport properties of a class of generalized exclusion processes. Analytical expressions for the transport-diffusion coefficient are derived by ignoring correlations. It is claimed that these expressions become exact in the hydrodynamic limit. In this Comment, we point out that (i) the influence of correlations upon the diffusion does not vanish in the hydrodynamic limit, and (ii) the expressions for the self- and transport diffusion derived by Arita et al. are special cases of results derived in [Phys. Rev. Lett. 111, 110601 (2013)].