The Hubble parameter in the early universe with viscous QCD matter and finite cosmological constant

@article{Tawfik2011TheHP,
  title={The Hubble parameter in the early universe with viscous QCD matter and finite cosmological constant},
  author={A. Tawfik},
  journal={Annalen der Physik},
  year={2011},
  volume={523}
}
  • A. Tawfik
  • Published 13 February 2011
  • Physics
  • Annalen der Physik
The evolution of a flat, isotropic and homogeneous universe is studied. The background geometry in the early phases of the universe is conjectured to be filled with causal bulk viscous fluid and dark energy. The energy density relations obtained from the assumption of covariant conservation of energy‐momentum tensor of the background matter in the early universe are used to derive the basic equation for the Hubble parameter H. The viscous properties described by ultra‐relativistic equations of… 

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References

SHOWING 1-10 OF 61 REFERENCES

Thermodynamics in the viscous early universe

Assuming that the matter in the background geometry is a free gas and that no phase transitions were occurring in the early Universe, we discuss the thermodynamics of this closed system using

Cosmological particle production and casual thermodynamics

The full linear causal Israel–Stewart–Hiscock theory of bulk viscous processes in relativistic cosmological fluids is reformulated as an effective phenomenological theory for describing particle

The Cosmological Constant and Dark Energy

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda: nowadays the concept is termed dark energy or

Cosmological consequences of a rolling homogeneous scalar field.

  • RatraPeebles
  • Physics
    Physical review. D, Particles and fields
  • 1988
TLDR
It is argued that a number of models in which the energy density of the scalar field red-shifts in a specific manner are studied could reconcile the low dynamical estimates of the mean mass density with the negligibly small spatial curvature preferred by inflation.

Density perturbations with relativistic thermodynamics

We investigate cosmological density perturbations in a covariant and gauge-invariant formalism, incorporating relativistic causal thermodynamics to give a self-consistent description. The gradient of

The Case for a positive cosmological Lambda term

Recent observations of Type 1a supernovae indicating an accelerating universe have once more drawn attention to the possible existence, at the present epoch, of a small positive Lambda-term

Dynamics of dark energy

We review in detail a number of approaches that have been adopted to try and explain the remarkable observation of our accelerating universe. In particular we discuss the arguments for and recent

Heavy ion collisions and lattice QCD at finite baryon density

We discuss a relation between the QCD thermodynamics obtained from a statistical analysis of particle production in heavy ion collisions at SPS and RHIC energies and recent LGT results at finite

Dissipative cosmological solutions

The exact general solution to the Einstein equations in a homogeneous Universe with a full causal viscous fluid source for the bulk viscosity index is found. We have investigated the asymptotic
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