A model of the late universe with viscous Zel’ldovich fluid and decaying vacuum

Nair, K. Rajagopalan; Mathew, Titus K.

doi:10.1007/s10509-018-3402-2

“…It is usually called stiff fluid in the literature, for that it is the most incompressible fluid permitted by relativistic causality. Such a kind of fluid surely has a large number of possible physical origins [26][27][28] different from what we have suggested. Interestingly, there are also a series of works called "holographic cosmology" [29,30], since after Fischler and Susskind showed the cosmologic holographic entropy bound could be saturated by w = 1 [9].…”

Section: Conclusion and Discussioncontrasting

confidence: 65%

Microscopic derivation of the Bekenstein-Hawking entropy for Schwarzschild black holes

Xiao

¹

2020

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In this paper, we successfully derive the Bekenstein-Hawking entropy for Schwarzschild black holes in various dimensions by using a non-trivial phase space. It is appealing to notice that the thermodynamics of a Schwarzschild black hole actually behaves like that of a 1-dimensional quantum mechanical system. Our result suggests that black hole should be viewed as a system with the equation of state P = ρ, and it also suggests that a holographic stage should exist in the early universe.

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“…Our work also suggests to take seriously the w = 1 stage of the early unverse. Fortunately the w = 1 stage has already been conjectured and studied in cosmology for many years from a number of different physical motivations, with the properties like enhancing stochastic gravitational waves, dark matter abundance and baryon asymmetry [25][26][27][28][29]. The future observational evidence of the existence of such a stage would have profound implications for the understanding of quantum gravity.…”

Section: Discussionmentioning

confidence: 99%

Running of effective dimension and cosmological entropy in early universe

Xiao

2020

Preprint

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In this paper, we suggest that the early universe starts from a high-energetic state with a two dimensional description and the state recovers to be four dimensional when the universe evolves into the radiation dominated phase. This scenario is consistent with the recent viewpoint that quantum gravity should be effectively two dimensional in the ultraviolet and recovers to be four dimensional in the infrared. A relationship has been established between the running of effective dimension and that of the entropy inside particle horizon of the universe, i.e., as the effective dimension runs from two to four, the corresponding entropy runs from the holographic entropy to the normal entropy appropriate to radiation. These results can be generalized to higher dimensional cases.

show abstract

“…Our work also suggests to take seriously the w = 1 stage of the early unverse. Fortunately the w = 1 stage has already been conjectured and studied in cosmology for many years from a number of different physical motivations, with the properties like enhancing stochastic gravitational waves, dark matter abundance and baryon asymmetry [25][26][27][28][29]. The future observational evidence of the existence of such a stage would have profound implications for the understanding of quantum gravity.…”

Section: Discussionmentioning

confidence: 99%

Running of effective dimension and cosmological entropy in early universe

Xiao

¹

2020

Eur. Phys. J. C

3

0

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In this paper, we suggest that the early universe starts from a high-energetic state with a two dimensional description and the state recovers to be four dimensional when the universe evolves into the radiation dominated phase. This scenario is consistent with the recent viewpoint that quantum gravity should be effectively two dimensional in the ultraviolet and recovers to be four dimensional in the infrared. A relationship has been established between the running of effective dimension and that of the entropy inside particle horizon of the universe, i.e., as the effective dimension runs from two to four, the corresponding entropy runs from the holographic entropy to the normal entropy appropriate to radiation. These results can be generalized to higher dimensional cases.

show abstract

A model of the late universe with viscous Zel’ldovich fluid and decaying vacuum

Cited by 5 publications

References 45 publications

Microscopic derivation of the Bekenstein-Hawking entropy for Schwarzschild black holes

Microscopic derivation of the Bekenstein-Hawking entropy for Schwarzschild black holes

Running of effective dimension and cosmological entropy in early universe

Running of effective dimension and cosmological entropy in early universe

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