title: Mechanical equivalent of quantum heat engines.
abstract: Quantum heat engines employ as working agents multilevel systems instead of classical gases. We show that under some conditions quantum heat engines are equivalent to a series of reservoirs at different altitudes containing balls of various weights. A cycle consists of picking up at random a ball from one reservoir and carrying it to the next, thereby performing or absorbing some work. In particular, quantum heat engines, employing two-level atoms as working agents, are modeled by reservoirs containing balls of weight 0 or 1. The mechanical model helps us prove that the maximum efficiency of quantum heat engines is the Carnot efficiency. Heat pumps and negative temperatures are considered.
authors.affiliation: Mas Liron, F30440 Saint Martial, France. arnaudj2@wanadoo.fr
authors.forename: Jacques
authors.initials: J
authors.lastname: Arnaud
authors.forename: Laurent
authors.initials: L
authors.lastname: Chusseau
authors.forename: Fabrice
authors.initials: F
authors.lastname: Philippe