Thermodynamics in spacetimes without horizons
File(s)
Published version
Author(s)
Isichei, Raymond
Magueijo, Joao
Type
Journal Article
Abstract
We consider the energetics and thermodynamics of spacetimes with no horizons, but endowed with a preferred timelike junction surface. They could arise as a limiting case of the gravastar and other constructions regularizing the interior of the horizon of a black hole, or from the conceptual cutting of a portion of a nonasymptotically flat space and gluing it with flat space. We find that such surfaces can be made to have zero energy, so that the energetics of such spaces is not encumbered by them. They do have a transverse pressure, fixed by the jump in surface gravity. A peculiar matter thermodynamics then follows, with well-defined entropy, temperature, and surface pressure, constrained by specific relations arising from the zero energy condition. This is confirmed by the Euclidean path integral, with the proviso that the Tolman-Ehrenfest temperature should be used. The entropy of the space is then the area of the timelike surface in units of a fundamental area, and the matter temperature is proportional to the transverse pressure and so the jump in surface gravity. However, when the gravitational action is added, the free energy of the surface is also zero. The fact that for some such spaces the temperature comes out negative raises interesting questions regarding the third “law” of thermodynamics.
Date Issued
2025-11-15
Date Acceptance
2025-10-06
Citation
Physical Review D, 2025, 112 (10)
ISSN
2470-0010
Publisher
American Physical Society
Journal / Book Title
Physical Review D
Volume
112
Issue
10
Copyright Statement
Published by the American Physical Society Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
License URL
Subjects
Astronomy & Astrophysics
BLACK-HOLES
EQUILIBRIUM
LAW
Physical Sciences
Physics
Physics, Particles & Fields
Science & Technology
Publication Status
Published
Article Number
L101502
Date Publish Online
2025-11-05