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

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 non-equilibrium system one can extract energy at the expense of increased entropy. This is a simple model of Maxwell's demon engine that extracts work out of a non-equilibrium bath by rectifying internal fluctuations. We point out the errors in the earlier results. We have obtained an analytical expression for the fluctuation-induced transport current in a non-equilibrium state and various cases of physical interest have been elucidated.