On the thermodynamics of matter creation in cosmology

Calvão, Maurício O.; Lima, J. A. S.; Waga, I.

doi:10.1016/0375-9601(92)90437-q

Cited by 298 publications

(395 citation statements)

References 12 publications

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“…In this section, the general radiative temperature law for adiabatic particle creation is reviewed, following the work of Lima et al [33][34][35][36]. A homogeneous, isotropic, and spatially flat universe is initially considered.…”

Section: General Radiative Temperature Law For Adiabatic Particlementioning

confidence: 99%

“…To this end, adiabatic particle creation is assumed [34][35][36]. The balance equations for the number of particles, entropy, and energy [36] can then be written as…”

Section: General Radiative Temperature Law For Adiabatic Particlementioning

confidence: 99%

“…Equation (3) can be rewritten as _ N=N ¼ Γ, using the total number N ∝ na 3 of particles in the comoving volume [36]. Keep in mind that the entropy per particle σ ¼ S=N is assumed to be constant [34,36] The local Gibbs relation should be valid even for the nonequilibrium process considered here [36]. Accordingly, the thermodynamic quantities are related to the temperature T by…”

Section: General Radiative Temperature Law For Adiabatic Particlementioning

confidence: 99%

“…However, the ΛCDM model has several theoretical difficulties [14][15][16][17], although it can elegantly explain the accelerated expansion of the late Universe [18][19][20][21][22][23]. To explain the acceleration, various models have been suggested, such as ΛðtÞCDM which assumes a timevarying cosmological term [24][25][26][27][28], bulk viscous models which assume a bulk viscosity for the cosmological fluid [29][30][31][32], and the creation of cold dark matter (CCDM) model which assumes the creation of cold dark matter [33][34][35][36][37][38][39][40][41][42][43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

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Cosmic microwave background radiation temperature in a dissipative universe

Komatsu

2015

Phys. Rev. D

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The relationship between the cosmic microwave background radiation temperature and the redshift, i.e., the T − z relation, is examined in a phenomenological dissipative model. The model contains two constant terms, as if a nonzero cosmological constant Λ and a dissipative process are operative in a homogeneous, isotropic, and spatially flat universe. The T − z relation is derived from a general radiative temperature law, as appropriate for describing nonequilibrium states in a creation of cold dark matter model. Using this relation, the radiation temperature in the late Universe is calculated as a function of a dissipation rate ranging fromμ ¼ 0, corresponding to a nondissipative lambda cold dark matter model, toμ ¼ 1, corresponding to a fully dissipative creation of cold dark matter model. The T − z relation forμ ¼ 0 is linear for standard cosmology and is consistent with observations. However, with increasing dissipation rateμ, the radiation temperature gradually deviates from a linear law because the effective equation-of-state parameter varies with time. When the background evolution of the Universe agrees with a fine-tuned pure lambda cold dark matter model, the T − z relation for lowμ matches observations, whereas the T − z relation for highμ does not. Previous work also found that a weakly dissipative model accords with measurements of a growth rate for clustering related to structure formations. These results imply that low dissipation is likely for the Universe. The weakly dissipative model should be further constrained by recent observations.

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Section: General Radiative Temperature Law For Adiabatic Particlementioning

confidence: 99%

“…To this end, adiabatic particle creation is assumed [34][35][36]. The balance equations for the number of particles, entropy, and energy [36] can then be written as…”

Section: General Radiative Temperature Law For Adiabatic Particlementioning

confidence: 99%

Section: General Radiative Temperature Law For Adiabatic Particlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cosmic microwave background radiation temperature in a dissipative universe

Komatsu

2015

Phys. Rev. D

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“…Among other possibilities to explain the present accelerating stage, inclusion of backreaction in the Einstein field equations through an (negative) effective pressure is much relevant in the context of cosmology and the gravitational production of particles [radiation or cold dark matter (CDM)] provides a mechanism for cosmic acceleration [6,[8][9][10]. In particular, in comparison with DE models, the particle creation scenario has a strong physical basis-nonequilibrium thermodynamics.…”

Section: Introductionmentioning

confidence: 99%

Particle production and universal thermodynamics

Saha

Chakraborty

2015

Gen Relativ Gravit

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In the present work, particle creation mechanism has been employed to the Universe as a thermodynamical system. The Universe is considered to be a spatially flat FRW model and cosmic fluid is chosen as a perfect fluid with a barotropic equation of statep = (γ − 1)ρ. By proper choice of the particle creation rate, expressions for the entropy and temperature have been determined at various stages of evolution of the Universe. Finally, using the deceleration parameter q as a function of the redshift parameter z based on recent observations, the particle creation rate has been evaluated and its variation at different epochs have been shown graphically.

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Entropy and creation cold dark matter models

Valentim

Jesus

2019

Astron Nachr

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Entropy is a fundamental concept from thermodynamics, and it can be used to study models in the context of the creation cold dark matter. A general feature of these models is that thermodynamic equilibrium is reached at last at the de Sitter era. Total Universe's entropy is calculated based on three terms: apparent horizon (S h ), entropy of matter (S m ), and entropy of radiation (S ). The constraints from total entropy come from the first and second derivatives (S ′ ≥ 0 and S ′′ < 0) to estimate the parameters of the model with the general matter creation rate. The preliminary outcomes suggest limits for these parameters. KEYWORDScreation of matter -dark matter -entropy -models 1

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On the thermodynamics of matter creation in cosmology

Cited by 298 publications

References 12 publications

Cosmic microwave background radiation temperature in a dissipative universe

Cosmic microwave background radiation temperature in a dissipative universe

Particle production and universal thermodynamics

Entropy and creation cold dark matter models

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