Heat flux in general quasifree fermionic right mover/left mover systems

TL;DR

This paper develops a theoretical framework for analyzing heat flux in quasifree fermionic chains, introducing right/left mover states, relating them to system velocities, and proving positive entropy production, thus generalizing previous models.

Contribution

It introduces a general class of right/left mover states in quasifree fermionic systems and relates their properties to heat flux and entropy production, expanding the understanding of nonequilibrium steady states.

Findings

System is thermodynamically nontrivial with positive entropy production.

Relates 2-point operator to asymptotic velocity of the system.

Generalizes well-known quasifree fermionic chain models.

Abstract

With the help of time-dependent scattering theory on the observable algebra of infinitely extended quasifree fermionic chains, we introduce a general class of so-called right mover/left mover states which are inspired by the nonequilibrium steady states for the prototypical nonequilibrium configuration of a finite sample coupled to two thermal reservoirs at different temperatures. Under the assumption of spatial translation invariance, we relate the 2-point operator of such a right mover/left mover state to the asymptotic velocity of the system and prove that the system is thermodynamically nontrivial in the sense that its entropy production rate is strictly positive. Our study of these not necessarily gauge-invariant systems covers and substantially generalizes well-known quasifree fermionic chains and opens the way for a more systematic analysis of the heat flux in such systems.