What decides the direction of a current?

TL;DR

This paper investigates the factors determining the direction of steady currents in nonequilibrium systems, emphasizing the roles of both dissipative and non-dissipative aspects beyond traditional thermodynamic laws.

Contribution

It highlights the importance of non-dissipative factors in deciding current direction, extending beyond the second law and entropy production considerations.

Findings

Non-dissipative aspects can fully determine current direction.

Both dissipative and non-dissipative factors influence steady currents.

Traditional thermodynamic laws are not solely sufficient to predict current direction.

Abstract

Nonequilibria show currents that are maintained as the result of a steady driving. We ask here what decides their direction. It is not only the second law, or the positivity of the entropy production that decides; also non-dissipative aspects often matter and sometimes completely decide.