The Hubble IR cutoff in holographic ellipsoidal cosmologies

TL;DR

This paper investigates the use of the Hubble IR cutoff in holographic ellipsoidal cosmologies, developing models with anisotropic dark energy that expand acceleratedly without approaching isotropy, thus exploring alternatives to standard FRW cosmologies.

Contribution

It introduces a new ellipsoidal holographic cosmological model using the Hubble IR cutoff, addressing limitations in isotropic models and analyzing anisotropic dark energy effects.

Findings

Cosmologies expand in all directions with acceleration.

Deviation from isotropy remains constant over time.

Dark energy can have quintessence or phantom equations of state.

Abstract

It is well known that for spatially flat FRW cosmologies, the holographic dark energy disfavours the Hubble parameter as a candidate for the IR cutoff. For overcoming this problem, we explore the use of this cutoff in holographic ellipsoidal cosmological models, and derive the general ellipsoidal metric induced by a such holographic energy density. Despite the drawbacks that this cutoff presents in homogeneous and isotropic universes, based on this general metric, we developed a suitable ellipsoidal holographic cosmological model, filled with a dark matter and a dark energy components. At late time stages, the cosmic evolution is dominated by a holographic anisotropic dark energy with barotropic equations of state. The cosmologies expand in all directions in accelerated manner. Since the ellipsoidal cosmologies given here are not asymptotically FRW, the deviation from homogeneity and isotropy of the universe on large cosmological scales remains constant during all cosmic evolution. This feature allows studied holographic ellipsoidal cosmologies to be ruled by an equation of state $\omega=p/\rho$, whose range belongs to quintessence or even phantom matter.