Samuel Lepe

Holographic principle and the dominant energy condition for Kasner type metrics

Abstract In this Letter we study adiabatic anisotropic matter filled Bianchi type I models of the Kasner form together with the cosmological holographic bound. We find that the dominant energy condition and the holographic bound give precisely the same constraint on the scale factor parameters that appear in the metric.

Fermions scattering in a three-dimensional extreme black-hole background

The absorption cross section for scattering of fermions off an extreme BTZ black hole is calculated. It is shown that, as in the case of scalar particles, an extreme BTZ black hole exhibits a vanishing absorption cross section, which is consistent with the vanishing entropy of such an object. Additionally, we give a general argument to prove that the particle flux near the horizon is zero. Finally, we show that the reciprocal space introduced previously in [1] gives rise to the same result and, therefore, it could be considered as the space where the scattering process takes place in an AdS spacetime.

Dark energy interacting with two fluids

A cosmological model of dark energy interacting with dark matter and another general component of the universe is investigated. We found general constraints on these models imposing an accelerated expansion. The same is also studied in the case for holographic dark energy.

Dynamics of viscous cosmologies in the full Israel-Stewart formalism

It is performed a detailed dynamical analysis for a bulk viscosity model in the full Israel-Stewart formalism for a spatially flat Friedmann-Robertson-Walker Universe. In our study we have considered the total cosmic fluid constituted by radiation, dark matter and dark energy. The dark matter fluid is treated as an imperfect fluid which has a bulk viscosity that depends on its energy density in the usual form

Holographic energy density on Hořava-Lifshitz cosmology

\xi(\rho_{m})=\xi_{0} \rho_{m}^{1/2}

Bulk-boundary interaction and the second law in Hořava-Lifshitz cosmology

, whereas the other components are assumed to behave as perfect fluids with constant EoS parameter. We show that the thermal history of the Universe is reproduced provided that the viscous coefficient satisfies the condition

An adiabatic approximation to the path integral for relativistic fermionic fields

\xi_{0}\ll 1

Closed universes can satisfy the holographic principle in three dimensions

, either for a zero or a suitable nonzero coupling between dark energy and viscous dark matter. In this case, the final attractor is a dark-energy-dominated, accelerating Universe, with effective EoS parameter in the quintessence-like, cosmological constant-like or phantom-like regime, in agreement with observations. As our main result, we show that in order to obtain a viable cosmological evolution and at the same time alleviating the cosmological coincidence problem via the mechanism of scaling solution, an explicit interaction between dark energy and viscous dark matter seems inevitable. This result is consistent with the well-known fact that models where dark matter and dark energy interact with each other have been proposed to solve the coincidence problem. Furthermore, by insisting in above, we show that in the present context a phantom nature of this interacting dark energy fluid is also favored.

Holographic approach for dark energy–dark matter interaction in curved FLRW spacetime

In Ho\v{r}ava-Lifshitz cosmology we use the holographic Ricci-like cut-off for the energy density proposed by L. N. Granda and A. Oliveros and under this framework we study, through the cosmic evolution at late times, the sign change in the amount of non-conservation energy (

Accelerated and decelerated expansion in a causal dissipative cosmology

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