Chzhan L., Chzhao Zh., Ma M. Black hole entropy in the Reissner-Nordström-de Sitter model

Abstract: The paper studies the development of the macroscopic methods of high-energy physics analysis. The authors consider the evolution of black holes within the phenomenological approach, analogous to classical thermodynamics, in which the black hole area determines its entropy, and the surface gravitation, correspondingly, - the temperature, in the framework of the relativist cosmological model (de Sitter universe). The research subject is the ways of calculation of effective thermodynamic properties of black holes. To calculate a black hole entropy, the authors apply the event horizon and cosmological horizon interdependence hypothesis. To accomplish the research task, the authors apply the system and structural-functional approaches, the methods of cosmology, relativistic mechanics and Einstein’s geometric theory of gravitation, in particular, the exact solutions of the Einstein field equations with the cosmological constant for the Reissner- Nordström metric for the space-time description. The authors find the analytical solution for the calculation of the total entropy of a spherically symmetric charged black hole in the Reissner- Nordström model for de Sitter universe. The paper shows that the expression for entropy includes not only the sum of entropies of the event horizon and cosmological horizon of the black hole, but also the additional term, taking into account their entanglement. The obtained results of black hole thermodynamics extend the analogy with the first law of thermodynamics, thus broadening the applicability of the approach to the cosmological studies. 

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