Saturation of the Holographic Principle for Spatially Closed Cosmological Models

2008 ◽  
Vol 30 ◽  
pp. 367-371
Author(s):  
P. Diaz ◽  
M.A. Per ◽  
A. Segui
Keyword(s):  
Cosmological Models ◽  
Holographic Principle

scholarly journals A Thermodynamic Approach to Holographic Dark Energy

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Orlando Luongo
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Cosmological Models ◽  
Holographic Principle ◽  
Thermodynamic Approach ◽  
Free Term ◽  
Spatial Curvature ◽  
Massless Particles ◽  
Information Density ◽  
Minimal Information

We propose a method to relate the holographic minimal information density to de Broglie’s wavelength at a given universe temperature T. To figure this out, we assume that the thermal length of massive and massless constituents represents the cut-off scale of the holographic principle. To perform our analysis, we suppose two plausible universe volumes, that is, the adiabatic and the horizon volumes, that is, V∝a3 and V∝H-3, respectively, assuming zero spatial curvature. With these choices in mind, we evaluate the thermal lengths for massive and massless particles and we thus find two cosmological models associated with late and early cosmological epochs. We demonstrate that both models depend upon a free term β which enters the temperature parametrization in terms of the redshift z. For the two treatments, we show evolving dark energy terms which can be compared with the ωCDM quintessence paradigm when the barotropic factor takes the formal values ω0=-1/3(2+β) and ω0=-1/3(1+2β), respectively, for late and early eras. From our analyses, we nominate the two models as viable alternatives to dark energy determined from thermodynamics in the field of the holographic principle.

scholarly journals A COVARIANT ENTROPY BOUND CONJECTURE ON THE DYNAMICAL HORIZON

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2467-2474 ◽  
Author(s):  
SONG HE ◽  
HONGBAO ZHANG
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Upper Bound ◽  
Supermassive Black Holes ◽  
Cosmological Models ◽  
Anthropic Principle ◽  
Holographic Principle ◽  
Cosmological Constant Problem ◽  
Entropy Contribution ◽  
Entropy Bound

We propose, as a compelling pattern for the holographic principle, a covariant entropy bound conjecture for more general dynamical horizons. Then we apply our conjecture to ΛCDM cosmological models, where we find that it imposes a novel upper bound, 10-90, on the cosmological constant for our own universe by taking into account the dominant entropy contribution from supermassive black holes, which thus provides an alternative macroscopic perspective for understanding the long-standing cosmological constant problem. As an intriguing implication of this conjecture, we also discuss the possible profound relation between the present cosmological constant, the origin of mass, and the anthropic principle.

scholarly journals Anisotropic cosmological models in Horndeski gravity

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Rafkat Galeev ◽  
Ruslan Muharlyamov ◽  
Alexei A. Starobinsky ◽  
Sergey V. Sushkov ◽  
Mikhail S. Volkov
Keyword(s):  
Cosmological Models ◽  
Anisotropic Cosmological Models

scholarly journals Late Time Attractors of Some Varying Chaplygin Gas Cosmological Models

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 769
Author(s):  
Martiros Khurshudyan ◽  
Ratbay Myrzakulov
Keyword(s):  
Dark Energy ◽  
Gravitational Interaction ◽  
Chaplygin Gas ◽  
Cosmological Models ◽  
Late Time ◽  
Time Behavior ◽  
Coincidence Problem ◽  
Energy Models ◽  
Non Linear ◽  
Bayesian Machine Learning

The goal of this paper is to study new cosmological models where the dark energy is a varying Chaplygin gas. This specific dark energy model with non-linear EoS had been often discussed in modern cosmology. Contrary to previous studies, we consider new forms of non-linear non-gravitational interaction between dark matter and assumed dark energy models. We applied the phase space analysis allowing understanding the late time behavior of the models. It allows demonstrating that considered non-gravitational interactions can solve the cosmological coincidence problem. On the other hand, we applied Bayesian Machine Learning technique to learn the constraints on the free parameters. In this way, we gained a better understanding of the models providing a hint which of them can be ruled out. Moreover, the learning based on the simulated expansion rate data shows that the models cannot solve the H0 tension problem.

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