Françoise Cornu, Michel Bauer
A toy model for thermal contact consists of a two-spin system, where each spin is flipped by a thermostat. The transition rates are determined from the modified detailed balance discussed in Ref.[1]. Generalized heat capacities, excess heats, the housekeeping entropy flow and the thermal conductivity are calculated. The joint probability distribution of the heat cumulated exchanges at any time is computed explicitly. We obtain the large deviation function of heat transfer via a variety of approaches. In particular, by a saddle-point method performed accurately, we obtain the explicit expressions not only of the large deviation function, but also of the amplitude prefactor, in the long-time probability density for the heat current. The following physical properties are discussed : the effects of typical time scales of the mesoscopic dynamics which do not appear in equilibrium statistical averages and the limit of purely energy dissipation towards a thermostat when its temperature goes to zero. We also derive some properties of the fluctuations in the two-spin system viewed as a thermal machine performing thermodynamical cycles.
View original:
http://arxiv.org/abs/1302.4540
No comments:
Post a Comment