Irreversible thermodynamical description of warm inflationary cosmological models

Harkó, Tiberiu; Sheikhahmadi, Haidar

doi:10.1016/j.dark.2020.100521

Cited by 22 publications

(14 citation statements)

References 139 publications

(172 reference statements)

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“…In the present section, we briefly review the fundamentals of the thermodynamics of irreversible processes in the presence of gravitationally induced matter creation. The main motivation for considering this formalism is related to the possibility of the interpretation of the nonconservation of the standard matter energy-momentum tensor in theories with torsion-matter coupling, as describing particle creation on a cosmological scale, a process that would naturally require the use of the irreversible thermodynamics of open systems [25][26][27][28][29][30]. Taking into account Equation (16), it turns out that in the presence of a torsion-matter coupling, the energy-momentum balance equation contains extra terms, as contrasted with the adiabatic conservation law of standard cosmology.…”

Section: Irreversible Thermodynamics Of Open Systemsmentioning

confidence: 99%

“…On the other hand, irreversible thermodynamics and thermodynamics of open systems is a widely studied field since it is useful in various applications [25][26][27][28][29][30][31][32][33]. One of them is related to the possibility of particle creation and matter production on cosmological scales, due to the appearance of a "heat"-type term which corresponds to the internal energy of the system.…”

Section: Introductionmentioning

confidence: 99%

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Gravitationally Induced Particle Production through a Nonminimal Torsion–Matter Coupling

Harkó

Saridakis

2021

Universe

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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 ΛCDM 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 ΛCDM 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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Section: Irreversible Thermodynamics Of Open Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gravitationally Induced Particle Production through a Nonminimal Torsion–Matter Coupling

Harkó

Saridakis

2021

Universe

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“…In an isotropic background, i.e. λ = 1, and when α tends to zero, the first slow-roll parameter goes back to the usual warm inflation relation [138,174,175]. To examine the validity of a theoretical model, one basic approach is to compare its predictions with the observations.…”

Section: Evolution Equations For Non-comoving Warm Inflationmentioning

confidence: 99%

Warm inflation with non-comoving scalar field and radiation fluid

Harkó

Sheikhahmadi

2021

Eur. Phys. J. C

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We consider a warm inflationary scenario in which the two major fluid components of the early Universe, the scalar field and the radiation fluid, evolve with distinct four-velocities. This cosmological configuration is equivalent to a single anisotropic fluid, expanding with a four-velocity that is a combination of the two fluid four-velocities. Due to the presence of anisotropies the overall cosmological evolution is also anisotropic. We obtain the gravitational field equations of the non-comoving scalar field–radiation mixture for a Bianchi Type I geometry. By assuming the decay of the scalar field, accompanied by a corresponding radiation generation, we formulate the basic equations of the warm inflationary model in the presence of two non-comoving components. By adopting the slow-roll approximation the theoretical predictions of the warm inflationary scenario with non-comoving scalar field and radiation fluid are compared in detail with the observational data obtained by the Planck satellite in both weak dissipation and strong dissipation limits, and constraints on the free parameters of the model are obtained. The functional forms of the scalar field potentials compatible with the non-comoving nature of warm inflation are also obtained.

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“…In an isotropic background, i.e. λ = 1, and when α tends to zero, the first slow roll parameter goes back to the usual warm inflation relation [136,173,174]. To examine the effectiveness of a theoretical model, one basic approach is to contrast its predictions with the observations.…”

Section: A Evolution Equations For Noncomoving Warm Inflationmentioning

confidence: 99%

“…Warm inflation represents presently a very active field of research, and it certainly represents an attractive and interesting alternative to the standard cold inflation/reheating scenarios. Different aspects of the cosmological evolution in the warm inflationary models have been investigated in great detail in [87]- [136].…”

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confidence: 99%

Warm inflation with non-comoving scalar field and radiation fluid

Harko,

Sheikhahmadi

2021

Preprint

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We consider a warm inflationary scenario in which the two dominant matter components present in the early Universe, the scalar field, and the radiation fluid, evolve with different four-velocities. This cosmological system is mathematically equivalent to a single anisotropic fluid, evolving with a four-velocity that is a function of the two independent fluid four-velocities. Due to the presence of the anisotropic physical parameters, the overall cosmological evolution is also anisotropic. We derive the gravitational field equations of the noncomoving scalar field-radiation mixture for a Bianchi type I geometry. By considering that the decay of the scalar field is accompanied by a corresponding radiation generation, we formulate the basic equations of the warm inflationary model in the presence of two noncomoving components. By adopting the slow roll approximation, we perform a detailed comparison of the theoretical predictions of the warm inflationary scenario with noncomoving scalar field and radiation fluid with the observational data obtained by the Planck satellite, by investigating both the weak dissipation and strong dissipation limits. Constraints on the free parameters of the model are obtained in both cases. The functional forms of the scalar field potentials compatible with the noncomoving nature of warm inflation are also derived.

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Irreversible thermodynamical description of warm inflationary cosmological models

Cited by 22 publications

References 139 publications

Gravitationally Induced Particle Production through a Nonminimal Torsion–Matter Coupling

Gravitationally Induced Particle Production through a Nonminimal Torsion–Matter Coupling

Warm inflation with non-comoving scalar field and radiation fluid

Warm inflation with non-comoving scalar field and radiation fluid

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