Abstract
It is well known that for spatially flat FRW cosmologies, the holographic dark energy disfavors 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 the studied holographic ellipsoidal cosmologies to be ruled by an equation of state omega =p/rho , whose range belongs to quintessence or even phantom matter.
Highlights
Using a Bianchi type-I metric, in [4] it was obtained a model which becomes to be an almost FRW in time that is consistent with current data of the CMB
It is remarkable that the generated metric allows one to consider accelerated expansion in all directions, which is in agreement with observations. This behavior is not typical for all Bianchi type-I cosmologies since often there are solutions where simultaneously some directional scale factors expand while others contract
The organization of the paper is as follows: in Sect. 2 we present the field equations for a spatially homogeneous and anisotropic Bianchi type-I universe with planar symmetry, and derive the general ellipsoidal metric induced by the considered holographic energy density
Summary
Using a Bianchi type-I metric, in [4] it was obtained a model which becomes to be an almost FRW in time that is consistent with current data of the CMB. An explicit field theory for the anisotropically stressed dark energy in a universe described by the Bianchi type-I metric was formulated in [12], and the parameters were constrained using the luminosity-redshift relationship of the SNIa data. For an ellipsoidal universe, which is Bianchi Type I cosmological model with highest symmetry in the spacial sections of the spacetime geometry, the actual skewness and shear of the dark energy component were constrained using Union data for supernovae [13].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
