Symmetry breaking gut phase transitions with irreversibilities

Diósi, Lajos; Keszthelyi, Bettina; Lukács, B.; Paál, György

doi:10.1016/0370-2693(85)91204-3

Cited by 24 publications

(14 citation statements)

References 11 publications

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“…Because of its generally negative sign many authors have addressed the question whether a cosmological bulk pressure may become sufficiently large to induce a phase of accelerated expansion ( [35][36][37][38][39][40][41]23,25]). The basic shortcoming of most previous attempts to establish scenarios of bulk-viscosity-driven inflation for cosmic media with conserved particle number is an apparently unphysical behavior of the thermodynamic quantities.…”

Section: Introductionmentioning

confidence: 99%

Cosmological particle production, causal thermodynamics, and inflationary expansion

Zimdahl

2000

Phys. Rev. D

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

101

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“…We shall analyze the model presented above. Note that this is not the only proposal in this stream, but many other similar models exist in the literature, based in similar ideas [7,[40][41][42][43][44][45][46][47][48][49]; the conclusions we obtained then should be pertinent for models alike.…”

Section: Bulk Viscosity Driving the Accelerated Expansionmentioning

confidence: 58%

Probing bulk viscous matter-dominated models with gamma-ray bursts

Montiel¹,

Bretón²

2011

J. Cosmol. Astropart. Phys.

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In this paper we extend the range of consistency of a constant bulk viscosity model to redshifts up to z ∼ 8.1. In this model the dark sector of the cosmic substratum is a viscous fluid with pressure p = −ζθ, where θ is the fluid-expansion scalar and ζ is the coefficient of bulk viscosity. Using the sample of 59 high-redshift GRBs reported by Wei (2010), we calibrate GRBs at low redshifts with the Union 2 sample of SNe Ia, avoiding then the circularity problem. Testing the constant bulk viscosity model with GRBs we found the best fit for the viscosity parameterζ in the range 0 <ζ < 3, being so consistent with previous probes; we also determined the deceleration parameter q0 and the redshift of transition to accelerated expansion. Besides we present an updated analysis of the model with CMB5-year data and CMB7-year data, as well as with the baryon acoustic peak BAO. From the statistics with CMB it turns out that the model does not describe in a feasible way the far far epoch of recombination of the universe, but is in very good concordance for epochs as far as z ∼ 8.1 till present.

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“…Some authors also discussed removing instabilities in the fluid power spectrum by treating viscosity as the physical origin for entropy perturbation, which in turn smoothing out anisotropies in the universe [30]- [32]. Cosmological viscosity also included studying early universe and entropy generation via cosmic inflation [33]- [39], and bulk viscosity driven late universe acceleration [40]- [44]. Recently, Brevik and Normann [45] inferred symmetry between the early-time and present-day viscous cosmology by using a bulk viscosity function proportional to the Hubble parameter H. Victor et al [46] discussed the bulk viscosity effects and matter production as an alternative for the description of the late times behavior of the observable universe.…”

Section: Introductionmentioning

confidence: 99%

Dissipative unified dark fluid model

El-khateeb

2019

Int. J. Mod. Phys. D

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We consider a unified dissipative dark fluid model. Our fluid contains an adiabatic part plus a bulk viscous one. The adiabatic part has the ability to asymptote between two power laws and so can interpolate between the dust and dark energy equations of state at early and late times. The dissipative part is a bulk viscous part with constant viscosity coefficient. The model is analyzed using the phase space methodology which helps to understand the dynamical behavior of the model in a robust manner without reference to the system solution. The parameters of the model are constrained through its asymptotic behavior and also through many observational constraints. We solve the Hubble parameter equation using numerical methods and results are plotted against the newest set of Hubble data. The model is tested using the Om(z) test which shows that this model although is a quintessence-like model, it slides through the phantom barrier. We study the model expectations for the evolution of the universe by studying the evolution of the deceleration parameter, the density of the universe, the effective equation of state parameter of the model and of its underlying dark energy package. We estimate the value of the present day viscosity coefficient of the cosmic fluid as 8 × 10 6 P a.s, which agrees with the work of many authors, e.g., Velten and Schwartz [26], Wang and Meng [27], and Sasidharan and Mathew [29]. We argue that this model is able to explain the behavior of the universe evolution.

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Symmetry breaking gut phase transitions with irreversibilities

Cited by 24 publications

References 11 publications

Cosmological particle production, causal thermodynamics, and inflationary expansion

Cosmological particle production, causal thermodynamics, and inflationary expansion

Probing bulk viscous matter-dominated models with gamma-ray bursts

Dissipative unified dark fluid model

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