Simple model for Maxwell's-demon-type information engine

Abstract

We have investigated the recently proposed self-consistent theory of fluctuation-induced transport. In this framework the subsystem under study is coupled to two independent baths at different temperatures. In this nonequilibrium system one can extract energy at the expense of increased entropy. This is a simple model of Maxwell's-demon-type engine that extracts work out of a nonequilbrium bath by rectifying internal fluctuations. We point out an error in the earlier results. We have obtained an analytical expression for the fluctuation-induced transport current in a nonequilibrium state that is valid at any temperatures, and various cases of physical interest have been elucidated.