title: Work measurement as a generalized quantum measurement.
abstract: We present a new method to measure the work w performed on a driven quantum system and to sample its probability distribution P(w). The method is based on a simple fact that remained unnoticed until now: Work on a quantum system can be measured by performing a generalized quantum measurement at a single time. Such measurement, which technically speaking is denoted as a positive operator valued measure reduces to an ordinary projective measurement on an enlarged system. This observation not only demystifies work measurement but also suggests a new quantum algorithm to efficiently sample the distribution P(w). This can be used, in combination with fluctuation theorems, to estimate free energies of quantum states on a quantum computer.
authors.affiliation: Departamento de Física, FCEyN, UBA, Ciudad Universitaria Pabellón 1, 1428 Buenos Aires, Argentina and IFIBA CONICET, FCEyN, UBA, Ciudad Universitaria Pabellón 1, 1428 Buenos Aires, Argentina.
authors.forename: Augusto J
authors.initials: AJ
authors.lastname: Roncaglia
authors.affiliation: Departamento de Física, FCEyN, UBA, Ciudad Universitaria Pabellón 1, 1428 Buenos Aires, Argentina.
authors.forename: Federico
authors.initials: F
authors.lastname: Cerisola
authors.affiliation: Departamento de Física, FCEyN, UBA, Ciudad Universitaria Pabellón 1, 1428 Buenos Aires, Argentina and IFIBA CONICET, FCEyN, UBA, Ciudad Universitaria Pabellón 1, 1428 Buenos Aires, Argentina.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Paz