Black hole horizons can hide positive heat capacity

作者：Biro Tamas S; Czinner Viktor G^*; Iguchi Hideo; Van Peter

来源：Physics Letters B, 2018, 782: 228-231.

DOI：10.1016/j.physletb.2018.05.035

• Black hole thermodynamics
• Entropy
• Heat capacity
• Thermal stability

Regarding the volume as independent thermodynamic variable we point out that black hole horizons can hide positive heat capacity and specific heat. Such horizons are mechanically marginal, but thermally stable. In the absence of a canonical volume definition, we consider various suggestions scaling differently with the horizon radius. Assuming Euler-homogeneity of the entropy, besides the Hawking temperature, apressure and a corresponding work term render the equation of state at the horizon thermally stable for any meaningful volume concept that scales larger than the horizon area. When considering also a Stefan-Boltzmann radiation like equation of state at the horizon, only one possible solution emerges: the Christodoulou-Rovelli volume, scaling as V similar to R-5, with an entropy S = 8/3S(BH).

• 出版日期2018-7-10