Cosmic antifriction and accelerated expansion

Zimdahl, Winfried; Schwarz, Dominik J.; Balakin, Alexander B.; Pavón, Diego

doi:10.1103/physrevd.64.063501

Cited by 347 publications

(338 citation statements)

References 51 publications

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“…This parallels related approaches for an inflationary phase in the early universe [8][9][10][11][12]. It was argued in [13,14], that a viscous pressure can play the role of an agent that drives the present acceleration of the Universe. Note that the possibility of a viscosity dominated late epoch of the Universe with accelerated expansion was already mentioned by Padmanabhan and Chitre in 1987 [15].…”

Section: Introductionmentioning

confidence: 85%

Bulk viscous cosmology with causal transport theory

Piattella

Fabris

Zimdahl

2011

J. Cosmol. Astropart. Phys.

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Abstract. We consider cosmological scenarios originating from a single imperfect fluid with bulk viscosity and apply Eckart's and both the full and the truncated Müller-Israel-Stewart's theories as descriptions of the non-equilibrium processes. Our principal objective is to investigate if the dynamical properties of Dark Matter and Dark Energy can be described by a single viscous fluid and how such description changes when a causal theory (Müller-IsraelStewart's, both in its full and truncated forms) is taken into account instead of Eckart's non-causal theory. To this purpose, we find numerical solutions for the gravitational potential and compare its behaviour with the corresponding ΛCDM case. Eckart's and the full causal theory seem to be disfavoured, whereas the truncated theory leads to results similar to those of the ΛCDM model for a bulk viscous speed in the interval 10 −11 ≪ c 2 b 10 −8 . Tentatively relating such value to a square propagation velocity of the order of T /m of perturbations in a non-relativistic gas of particles with mass m at the epoch of matter-radiation equality, this may be compatible with a mass range 0.1 GeV m ≪ 100 GeV.

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Section: Introductionmentioning

confidence: 85%

Bulk viscous cosmology with causal transport theory

Piattella

Fabris

Zimdahl

2011

J. Cosmol. Astropart. Phys.

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“…The corresponding time-like vector ζ i is shown to exist for FLRW space-time, and the explicit example of the so-called generalized equilibrium states has been found in [29]. Starting from this fact we have studied in [14,17] the consequences of the appearance of the antifriction force. The force (14) gives the Stokes force when ωqm = λ and the Langevin force when ωqmU i = κξ i .…”

Section: Force Field Modelingmentioning

confidence: 99%

“…There exists a number of dark energy candidates, the best known are a cosmological constant and different quintessence scenarios ( [5,6,7,8,9,10,11,12]). Negative pressure may also be the consequence of self-interactions in gas models of the Universe [13,14,15,16,17]. In particular, an "antifrictional" force, self-consistently exerted on the particles of the cosmic substratum, was shown to provide an alternative explanation for an accelerated expansion of the Universe [14,16].…”

Section: Introductionmentioning

confidence: 99%

“…Negative pressure may also be the consequence of self-interactions in gas models of the Universe [13,14,15,16,17]. In particular, an "antifrictional" force, self-consistently exerted on the particles of the cosmic substratum, was shown to provide an alternative explanation for an accelerated expansion of the Universe [14,16]. This approach relies on the fact that the cosmological principle is compatible with the existence of a certain class of (hypothetical) microscopic one-particle forces, which manifest themselves as "source" terms in the macroscopic perfect fluid balance equations.…”

Section: Introductionmentioning

confidence: 99%

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Curvature Coupling and Accelerated Expansion of the Universe

Balakin

2004

General Relativity and Gravitation

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A new exactly solvable model for the evolution of relativistic kinetic system interacting with an internal stochastic reservoir under the influence of a gravitational background expansion is established. This model of selfinteraction is based on the relativistic kinetic equation for the distribution function defined in the extended phase space. The supplementary degree of freedom is described by the scalar stochastic variable (Langevin source), which is considered to be the constructive element of the effective oneparticle force. The expansion of the Universe is shown to be accelerated for the suitable choice of the non-minimal self-interaction force.

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“…The extra terms thus produced can be used to cancel the extra terms in equation (2). Let ζ = ∂F (ψ, R)/∂ R / ∂F (ψ, R)/∂ R .…”

Section: General Conformal Transformationsmentioning

confidence: 99%

Conformal transformations and accelerated cosmologies

Crooks

Frampton

2006

Phys. Rev. D

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A cosmological theory that predicts a late-time accelerated attractor with a constant dark matter to dark energy ratio can be said to solve the Coincidence Problem. Such cosmologies are naturally generated in the context of non-standard gravity theories under conformal transformation because of the resulting couplings between scalar fields and matter. The present work examines four classes of these transformed theories and finds that only a small subset-those with a single scalar field-are capable of solving the Coincidence Problem.

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Cosmic antifriction and accelerated expansion

Cited by 347 publications

References 51 publications

Bulk viscous cosmology with causal transport theory

Bulk viscous cosmology with causal transport theory

Curvature Coupling and Accelerated Expansion of the Universe

Conformal transformations and accelerated cosmologies

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