Thermodynamics of a quantized electromagnetic field in rectangular cavities with perfectly conducting walls

摘要

The thermodynamical properties of a quantized electromagnetic field inside abox with perfectly conducting walls are studied using a regularization schemethat permits to obtain finite expressions for the thermodynamic potentials. Thesource of ultraviolet divergences is directly isolated in the expression forthe density of modes, and the logarithmic infrared divergences are regularizedimposing the uniqueness of vacuum and, consequently, the vanishing of theentropy in the limit of zero temperature. We thus obtain corrections to theCasimir energy and pressures, and to the specific heat that are due totemperature effects; these results suggest effects that could be testedexperimentally.