Energy transmutation in nonequilibrium quantum systems

TL;DR

This paper studies energy transmutation in nonequilibrium quantum star graph systems, analyzing how heat and chemical potential energy convert under various conditions with exact results for scale-invariant interactions.

Contribution

It provides a comprehensive analysis of energy transmutation in quantum junctions, including exact solutions and efficiency coefficients, considering particle statistics and nonlinear effects.

Findings

Energy transmutation occurs between heat and chemical potential energy.

Results are exact for scale-invariant interactions across all parameters.

Energy transmutation efficiency depends on particle statistics.

Abstract

We investigate the particle and heat transport in quantum junctions with the geometry of star graphs. The system is in a nonequilibrium steady state, characterized by the different temperatures and chemical potentials of the heat reservoirs connected to the edges of the graph. We explore the Landauer-Buettiker state and its orbit under parity and time reversal transformations. Both particle number and total energy are conserved in these states. However the heat and chemical potential energy are in general not separately conserved, which gives origin to a basic process of energy transmutation among them. We study both directions of this process in detail, introducing appropriate efficiency coefficients. For scale invariant interactions in the junction our results are exact and explicit. They cover the whole parameter space and take into account all nonlinear effects. The energy transmutation depends on the particle statistics.