Nonequilibrium current fluctuation in an AB ring with a quantum dot

Nonequilibrium steady states (NESS) and current fluctuations are investigated for a noninteracting system consisting of a single-level quantum dot (QD) embedded in an Aharonov–Bohm (AB) ring. With the aid of asymptotic incoming fields, NESS are explicitly constructed. In terms of current fluctuations, the interplay between particle-like and wave-like behaviors of electrons is investigated. The current–current correlation function is found to be related to the differential conductance (an extension of the Kubo formula) and a relative entropy production is shown to be nonnegative at NESS.