Transitional steady states of exchange dynamics between finite quantum systems

TL;DR

This paper investigates unique nonequilibrium states in finite quantum systems where energy and particle exchange rates evolve stepwise, influenced by interference effects, yet still obey Onsager's reciprocal relations.

Contribution

It reveals a new form of nonequilibrium states in finite quantum systems with stepwise exchange rate evolution and boundary interference effects, expanding understanding beyond infinite system steady states.

Findings

Exchange rates change stepwise over time.

Sign and magnitude depend on system size differences.

Onsager's reciprocal relation remains valid.

Abstract

We examine energy and particle exchange between finite-sized quantum systems and find a new form of nonequilibrium states. The exchange rate undergoes stepwise evolution in time, and its magnitude and sign dramatically change according to system size differences. The origin lies in interference effects contributed by multiply scattered waves at system boundaries. Although such characteristics are utterly different from those of true steady state for infinite systems, Onsager's reciprocal relation remains universally valid.