title: Generalized Jarzynski equality under nonequilibrium feedback control.
abstract: The Jarzynski equality is generalized to situations in which nonequilibrium systems are subject to a feedback control. The new terms that arise as a consequence of the feedback describe the mutual information content obtained by measurement and the efficacy of the feedback control. Our results lead to a generalized fluctuation-dissipation theorem that reflects the readout information, and they can be experimentally tested using small thermodynamic systems. We illustrate our general results by introducing an "information ratchet", which can transport a Brownian particle in one direction and extract positive work from the particle.
authors.affiliation: Department of Physics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sagawa
authors.forename: Masahito
authors.initials: M
authors.lastname: Ueda