Multiple phase transitions in a system of exclusion processes with limited reservoirs of particles and fuel carriers

TL;DR

This paper extends the TASEP model to include limited resources like particles and fuel carriers, revealing multiple phase transitions and resource-dependent dynamics in non-equilibrium transport systems.

Contribution

It introduces a novel extension of TASEP with two limited resources, uncovering complex phase behavior and multiple transitions not seen in traditional models.

Findings

Multiple phase transitions occur with varying exit rates.

Limited resources lead to a broad coexistence region.

Fluctuations in particle density are unaffected by fuel carrier fluctuations.

Abstract

The TASEP is a paradigmatic model from non-equilibrium statistical physics, which describes particles hopping along a lattice of discrete sites. The TASEP is applicable to a broad range of different transport systems, but does not consider the fact that in many such systems the availability of resources required for the transport is limited. In this paper we extend the TASEP to include the effect of a limited number of two different fundamental transport resources: the hopping particles, and the "fuel carriers", which provide the energy required to drive the system away from equilibrium. As as consequence, the system's dynamics are substantially affected: a "limited resources" regime emerges, where the current is limited by the rate of refuelling, and the usual coexistence line between low and high particle density opens into a broad region on the phase plane. Due to the combination of a limited amount of both resources, multiple phase transitions are possible when increasing the exit rate beta for a fixed entry rate alpha. This is a new feature that can only be obtained by the inclusion of both kinds of limited resources. We also show that the fluctuations in particle density in the LD and HD phases are unaffected by fluctuations in the number of loaded fuel carriers, except by the fact that when these fuel resources become limited, the particle hopping rate is severely reduced.