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arXiv · 2107.01937

Gravitationally Induced Particle Production through a Nonminimal Torsion-Matter Coupling

Tiberiu Harko·Francisco S. N. Lobo·Emmanuel N. Saridakis
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Abstract

We investigate the possibility of gravitationally generated particle production via the mechanism of nonminimal torsion--matter coupling. An intriguing feature of this theory is that the divergence of the matter energy--momentum tensor does not vanish identically. We explore the physical and cosmological implications of the nonconservation of the energy--momentum tensor by using the formalism of irreversible thermodynamics of open systems in the presence of matter creation/annihilation. The particle creation rates, pressure, and the expression of the comoving entropy are obtained in a covariant formulation and discussed in detail. Applied together with the gravitational field equations, the thermodynamics of open systems lead to a generalization of the standard $\Lambda$CDM cosmological paradigm, in which the particle creation rates and pressures are effectively considered as components of the cosmological fluid energy--momentum tensor. We consider specific models, and we show that cosmology with a torsion--matter coupling can almost perfectly reproduce the $\Lambda$CDM scenario, while it additionally gives rise to particle creation rates, creation pressures, and entropy generation through gravitational matter production in both low and high redshift limits.

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Tiberiu Harko, Francisco S. N. Lobo, Emmanuel N. Saridakis. 2021-07-05. Gravitationally Induced Particle Production through a Nonminimal Torsion-Matter Coupling. https://doi.org/10.3390/universe7070227

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