Li, Y.; Milton, K.A.; Parashar, P.; Hong, L. Negativity of the Casimir Self-Entropy in Spherical Geometries. Entropy2021, 23, 214.
Li, Y.; Milton, K.A.; Parashar, P.; Hong, L. Negativity of the Casimir Self-Entropy in Spherical Geometries. Entropy 2021, 23, 214.
Li, Y.; Milton, K.A.; Parashar, P.; Hong, L. Negativity of the Casimir Self-Entropy in Spherical Geometries. Entropy2021, 23, 214.
Li, Y.; Milton, K.A.; Parashar, P.; Hong, L. Negativity of the Casimir Self-Entropy in Spherical Geometries. Entropy 2021, 23, 214.
Abstract
It has been recognized for some time that even for perfect conductors, the interaction Casimir entropy, due to quantum/thermal fluctuations, can be negative. This result was not considered problematic because it was thought that the self-entropies of the bodies would cancel this negative interaction entropy, yielding a total entropy that was positive. In fact, this cancellation seems not to occur. The positive self entropy of a perfectly conducting sphere does indeed just cancel the negative interaction entropy of a system consisting of a perfectly conducting sphere and plate, but a model with weaker coupling in general possesses a regime where negative self-entropy appears. The physical meaning of this surprising result remains obscure. In this paper we re-examine these issues, using improved physical and mathematical techniques, partly based on the Abel-Plana formula, and present numerical results for arbitrary temperatures and couplings, which exhibit the same remarkable features.
Keywords
Entropy; free energy; Casimir effect
Subject
PHYSICAL SCIENCES, Acoustics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
