Regular Article – Theoretical Physics
Thermodynamic constraints on matter creation models
Departamento de Física, Instituto de Ciências Ambientais, Químicas e Farmacêuticas-ICAQF, Universidade Federal de São Paulo (UNIFESP), Unidade José Alencar, Rua São Nicolau No. 210, 09913-030, Diadema, SP, Brazil
2 Universidade Estadual Paulista (UNESP), Câmpus Experimental de Itapeva, Rua Geraldo Alckmin 519, Vila N. Sra. de Fátima, 18409-010, Itapeva, SP, Brazil
3 Departamento de Física e Química, Faculdade de Engenharia de Guaratinguetá, Universidade Estadual Paulista (UNESP), Av. Dr. Ariberto Pereira da Cunha 333, 12516-410, Guaratinguetá, SP, Brazil
Accepted: 21 October 2020
Published online: 9 November 2020
Entropy is a fundamental concept from Thermodynamics and it can be used to study models on context of Creation Cold Dark Matter (CCDM). From conditions on the first () (throughout the present work we will use dots to indicate time derivatives and dashes to indicate derivatives with respect to scale factor) and second order () time derivatives of total entropy in the initial expansion of Sitter through the radiation and matter eras until the end of Sitter expansion, it is possible to estimate the intervals of parameters. The total entropy () is calculated as sum of the entropy at all eras ( and ) plus the entropy of the event horizon (). This term derives from the Holographic Principle where it suggests that all information is contained on the observable horizon. The main feature of this method for these models are that thermodynamic equilibrium is reached in a final de Sitter era. Total entropy of the universe is calculated with three terms: apparent horizon (), entropy of matter () and entropy of radiation (). This analysis allows to estimate intervals of parameters of CCDM models.
© The Author(s) 2020
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