Is the Decaying Vacuum Model a Complete Description of Cosmic Expansion?

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SUMMARY

The Decaying Vacuum Model presents a comprehensive framework for cosmic expansion, emerging from an initial de Sitter stage and transitioning through radiation, matter, and dark energy epochs. This model effectively addresses the initial singularity and the horizon problem by employing a running vacuum energy density defined as a power series of the Hubble rate: ρΛ(H). While it closely aligns with the ΛCDM model in late-time cosmic history, it offers a more detailed account of past cosmic evolution. Critics note that it may primarily serve as a method of "curve fitting," yet its implications for understanding cosmic dynamics are significant.

PREREQUISITES
  • Understanding of General Relativity and Quantum Cosmology
  • Familiarity with cosmological models, specifically the ΛCDM model
  • Knowledge of vacuum energy concepts in high-energy physics
  • Basic grasp of the Hubble parameter and its significance in cosmology
NEXT STEPS
  • Research the implications of running vacuum energy density in cosmology
  • Study the transition from inflation to the radiation epoch in detail
  • Explore the mathematical framework of the Decaying Vacuum Model
  • Investigate the horizon problem and its solutions in modern cosmology
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Astronomers, cosmologists, and theoretical physicists interested in advanced models of cosmic expansion and the underlying principles of vacuum energy dynamics.

wolram
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What do you guys think of this new model?


[4] arXiv:1209.2802 [pdf, ps, other]
Expansion History with Decaying Vacuum: A Complete Cosmological ScenJ. A. S. Lima, S. Basilakos, Joan So
Comments: LaTeX, 11 pages and one figure
Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Extragalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We propose a novel cosmological scenario with the space-time emerging from a pure initial de Sitter stage and subsequently evolving into the radiation, matter and dark energy dominated epochs, thereby avoiding the initial singularity and providing a complete description of the expansion history and a natural solution to the horizon problem. The model is based on a running vacuum energy density which evolves as a power series of the Hubble rate: \rho_{\Lambda}(H). The transit from the inflation into the standard radiation epoch is universal, giving a clue for a successful description of the graceful exit. The Universe is finally driven into the present slow accelerated expansion, characterized by a residual (but dynamical) vacuum energy: \rho_{\Lambda}(H)=c_0+c_2H^2. While the resulting late time cosmic history is very close to the concordance \Lambda CDM model, the new unified framework embodies a more complete past cosmic evolution than the standard cosmology
 
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It doesn't seem to be a new model so much as "curve fitting" but it looks like interesting and useful curve fitting.
 

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