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

In summary, the authors propose a cosmological scenario where the initial de Sitter stage evolves into radiation, matter, and dark energy dominated epochs, avoiding the initial singularity and providing a complete description of the expansion history. This is achieved through a running vacuum energy density that evolves as a power series of the Hubble rate. While the resulting late time cosmic history closely resembles the standard \Lambda CDM model, this new framework offers a more complete past cosmic evolution.
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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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  • #2
It doesn't seem to be a new model so much as "curve fitting" but it looks like interesting and useful curve fitting.
 

1. What is the Decaying Vacuum Model?

The Decaying Vacuum Model is a theory in physics that proposes the existence of a decaying vacuum energy. It suggests that the vacuum of space is not truly empty and contains energy that decays over time, which could explain the expansion of the universe.

2. How does the Decaying Vacuum Model differ from the Cosmological Constant Model?

The Cosmological Constant Model proposes a constant energy density of the vacuum, while the Decaying Vacuum Model suggests that this energy density decreases over time. This difference could have significant implications for our understanding of the expansion of the universe.

3. What evidence supports the Decaying Vacuum Model?

One piece of evidence for the Decaying Vacuum Model is the observed acceleration of the expansion of the universe. This acceleration could be explained by a decaying vacuum energy, as the energy density decreases, the expansion of the universe would increase. Additionally, the model also helps to resolve some issues with the Cosmological Constant Model, such as the "fine-tuning problem."

4. Are there any challenges or criticisms of the Decaying Vacuum Model?

One criticism of the Decaying Vacuum Model is the lack of direct observational evidence for a decaying vacuum energy. Additionally, some argue that the model is overly complex and may not be necessary to explain the expansion of the universe. There is also debate over whether the model is falsifiable, meaning it can be proven true or false through observation or experimentation.

5. How does the Decaying Vacuum Model impact our understanding of the universe?

If the Decaying Vacuum Model is proven to be true, it would significantly change our understanding of the universe and its future. The model suggests that the universe will continue to expand and eventually reach a state of maximum entropy, known as the "heat death" of the universe. This has implications for the fate of our universe and the potential for life to exist in the distant future.

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