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

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 a 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 ß for a fixed entry rate a. 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.