Spurious symmetry-broken phase in a bidirectional two-lane ASEP with narrow entrances: A perspective from mean field analysis and current minimization principle

TL;DR

This paper uses mean field analysis and current minimization to show that a certain symmetry-broken phase does not exist in a bidirectional two-lane ASEP with narrow entrances, clarifying controversy in the field.

Contribution

It demonstrates the non-existence of one symmetry-broken phase in this ASEP model, providing insights into phase behavior and phase boundary prediction.

Findings

One symmetry-broken phase does not exist in the model.

Exponential decay observed near phase boundary.

Results may generalize to other ASEP models.

Abstract

As one of the paradigmatic models of non-equilibrium systems, the asymmetric simple exclusion process (ASEP) has been widely used to study many physical, chemical, and biological systems. The ASEP shows a range of nontrivial macroscopic phenomena, among which, the spontaneous symmetry breaking has gained much attention. Nevertheless, as a basic problem, it has been controversial that whether there exist one or two symmetry-broken phases in the ASEP. Based on mean field analysis and current minimization principle, this paper demonstrates that one of the broken-symmetry phases does not exist in a bidirectional two-lane ASEP with narrow entrances. Moreover, an exponential decay feature is observed, which has been used to predict phase boundary in the thermodynamic limit. Our findings might be generalized to other ASEP models and thus deepen the understanding of the spontaneous symmetry breaking in non-equilibrium systems.