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Structural Statistical Quantifiers and Thermal Features of Quantum Systems
Article

Negativity of the Casimir Self-Entropy in Spherical Geometries

by 1,†, 2,*,†, 3,† and 4
1
Department of Physics, Nanchang University, Nanchang 330031, China
2
Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA
3
John A. Logan College, Carterville, IL 62918, USA
4
Institute of Space Science and Technology, Nanchang University, Nanchang 330031, China
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Academic Editor: Johan Anderson
Entropy 2021, 23(2), 214; https://doi.org/10.3390/e23020214
Received: 27 January 2021 / Revised: 4 February 2021 / Accepted: 4 February 2021 / Published: 10 February 2021
(This article belongs to the Special Issue Entropy-based Methods in In and Out of Equilibrium Systems)
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. View Full-Text
Keywords: Casimir free energy; entropy; Abel–Plana formula Casimir free energy; entropy; Abel–Plana formula
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MDPI and ACS Style

Li, Y.; Milton, K.A.; Parashar, P.; Hong, L. Negativity of the Casimir Self-Entropy in Spherical Geometries. Entropy 2021, 23, 214. https://doi.org/10.3390/e23020214

AMA Style

Li Y, Milton KA, Parashar P, Hong L. Negativity of the Casimir Self-Entropy in Spherical Geometries. Entropy. 2021; 23(2):214. https://doi.org/10.3390/e23020214

Chicago/Turabian Style

Li, Yang, Kimball A. Milton, Prachi Parashar, and Lujun Hong. 2021. "Negativity of the Casimir Self-Entropy in Spherical Geometries" Entropy 23, no. 2: 214. https://doi.org/10.3390/e23020214

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