Collisional equilibrium, particle production, and the inflationary universe

Zimdahl, Winfried; Triginer, Josep; Pavón, Diego

doi:10.1103/physrevd.54.6101

Cited by 55 publications

(64 citation statements)

References 26 publications

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“…In particular, one may think here of quantum particle production out of the gravitational field [12][13][14]. The manifestation of cosmological particle creation as an effective bulk pressure has initiated a series of papers discussing a fluid phenomenological approach to cosmological particle production [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. The present paper will mainly explore this second aspect as well.…”

Section: Introductionmentioning

confidence: 99%

Cosmological particle production, causal thermodynamics, and inflationary expansion

Zimdahl

2000

Phys. Rev. D

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101

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Combining the equivalence between cosmological particle creation and an effective viscous fluid pressure with the fact that the latter represents a dynamical degree of freedom within the secondorder Israel-Stewart theory for imperfect fluids, we reconsider the possibility of accelerated expansion in fluid cosmology. We find an inherent self-limitation for the magnitude of an effective bulk pressure which is due to adiabatic (isentropic) particle production. For a production rate which depends quadratically on the Hubble rate we confirm the existence of solutions which describe a smooth transition from inflationary to noninflationary behavior and discuss their interpretation within the model of a decaying vacuum energy density. An alternative formulation of the effective imperfect fluid dynamics in terms of a minimally coupled scalar field is given. The corresponding potential is discussed and an entropy equivalent for the scalar field is found.

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Section: Introductionmentioning

confidence: 99%

Cosmological particle production, causal thermodynamics, and inflationary expansion

Zimdahl

2000

Phys. Rev. D

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101

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“…(41) considerably simplifies, but also we do not need the r equation (42). The resulting dynamical system is…”

Section: A Warm Inflation With Bulk Viscosity π = −3ζhmentioning

confidence: 99%

“…In a universe with two components, it can be shown [42,43] that the temperature of each of the components satisfies the equatioṅ…”

Section: B Warm Inflation With γ ∝ Hmentioning

confidence: 99%

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Asymptotic behavior of the warm inflation scenario with viscous pressure

Mimoso¹,

Nunes²,

Pavón³

2006

Phys. Rev. D

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We analyze the dynamics of models of warm inflation with general dissipative effects. We consider phenomenological terms both for the inflaton decay rate and for viscous effects within matter.We provide a classification of the asymptotic behavior of these models and show that the existence of a late-time scaling regime depends not only on an asymptotic behavior of the scalar field potential, but also on an appropriate asymptotic behavior of the inflaton decay rate. There are scaling solutions whenever the latter evolves to become proportional to the Hubble rate of expansion regardless of the steepness of the scalar field exponential potential. We show from thermodynamic arguments that the scaling regime is associated to a power-law dependence of the matter-radiation temperature on the scale factor, which allows a mild variation of the temperature of the matter/radiation fluid. We also show that the late time contribution of the dissipative terms alleviates the depletion of matter, and increases the duration of inflation. PACS numbers: 98.80.Cq, 47.75+f

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“…In other words, the process of particle creation out of gravitational energy is basically an irreversible phenomenon, capable of explaining the entropy burst in the expanding universe. A detailed study of the thermodynamics of the particle creation with changing specific entropy have been discussed by Lima et al 3 , Calvão et al 4 , Lima and Germano 5 , Lima et al 6 , and Zimdahl et al 7 . Johri and Desikan 8 studied Friedmann-Robertson-Walker (FRW) models with particle creation.…”

Section: Introductionmentioning

confidence: 99%

Viscous FRW Models With Particle Creation in Early Universe

Singh

2012

Mod. Phys. Lett. A

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We discuss the dynamical effects of bulk viscosity and particle creation on the early evolution of the Friedmann -Robertson -Walker model in the framework of open thermodynamical systems. We consider bulk viscosity and particle creation as separate irreversible processes. Exact solutions of the Einstein field equations are obtained by using the "gammalaw" equation of state p = (γ − 1)ρ, where the adiabatic parameter γ varies with scale factor of the metric. We consider the cosmological model to study the early phases of the evolution of the universe as it goes from an inflationary phase to a radiation -dominated era in the presence of bulk viscosity and particle creation. Analytical solutions are obtained for particle number density and entropy for all models. It is found that, by choosing appropriate functions for particle creation rate and bulk viscous coefficient, the models exhibit singular and non-singular beginnings.

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Collisional equilibrium, particle production, and the inflationary universe

Cited by 55 publications

References 26 publications

Cosmological particle production, causal thermodynamics, and inflationary expansion

Cosmological particle production, causal thermodynamics, and inflationary expansion

Asymptotic behavior of the warm inflation scenario with viscous pressure

Viscous FRW Models With Particle Creation in Early Universe

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