Spontaneous symmetry breaking in a bridge model fed by junctions

TL;DR

This paper introduces a 1D bridge model with two particle species that exhibit spontaneous symmetry breaking, hysteresis, and complex phase behavior, supported by mean field analysis and Monte Carlo simulations.

Contribution

It presents a novel 1D model demonstrating spontaneous symmetry breaking and hysteresis in a driven particle system with junctions, including a unique kink in the phase transition line.

Findings

Spontaneous symmetry breaking occurs for certain injection/extraction rates.

Hysteresis is observed when varying extraction rates.

A kink in the transition line indicates non-equilibrium phase transition behavior.

Abstract

We introduce a class of 1D models mimicking a single-lane bridge with two junctions and two particle species driven in opposite directions. The model exhibits spontaneous symmetry breaking (SSB) for a range of injection/extraction rates. In this phase the steady state currents of the two species are not equal. Moreover there is a co-existence region in which the symmetry broken phase co-exists with a symmetric phase. Along a path in which the extraction rate is varied, keeping the injection rate fixed and large, hysteresis takes place. The mean field phase diagram is calculated and supporting Monte-Carlo simulations are presented. One of the transition lines exhibits a kink, a feature which cannot exist in transition lines of equilibrium phase transitions.