Thermodynamics and classification of cosmological models in the Horava-Lifshitz theory of gravity

Abstract

We study thermodynamics of cosmological models in the Horava-Lifshitz theory of gravity, and systematically investigate the evolution of the universe filled with a perfect fluid that has the equation of state p = wρ, where p and ρ denote, respectively, the pressure and energy density of the fluid, and w is an arbitrary real constant. Depending on specific values of the free parameters involved in the models, we classify all of them into various cases. In each case the main properties of the evolution are studied in detail, including the periods of deceleration and/or acceleration, and the existence of big bang, big crunch, and big rip singularities. We pay particular attention on models that may give rise to a bouncing universe.

Stability of spin-0 graviton and strong coupling in Horava-Lifshitz theory of gravity

“…Scale-invariant super-horizon curvature perturbations can also be produced without inflation [8][9][10][11][12][13], and dark matter and dark energy can have their geometric origins [14,15]. Furthermore, bouncing universe can be easily constructed due to the high-order derivative terms of the spacetime curvature [16][17][18]. For detail, we refer readers to [19] and references therein.…”

Aspects of Hořava–lifshitz Cosmology

“…ǫ ijk is the totally antisymmetric unit tensor, λ is a dimensionless constant and the variables κ, w and µ are constants. Finally, we mention that in action (2) we have already performed the usual analytic continuation of the parameters µ and w of the original version of Hořava-Lifshitz gravity, since such a procedure is required in order to obtain a realistic cosmology [13,14,28,38] (although it could fatally affect the gravitational theory itself).…”

“…Additionally, application of Hořava-Lifshitz gravity as a cosmological framework gives rise to Hořava-Lifshitz cosmology, which proves to lead to interesting behavior [12]. In particular, one can examine specific solution subclasses [13][14][15], the phase-space behavior [16][17][18], the gravitational wave production [19], the perturbation spectrum [20][21][22], the matter bounce [23][24][25][26], the black hole properties [27][28][29], the dark energy phenomenology [30][31][32][33], the observational constraints on the parameters of the theory [34][35][36], the astrophysical phenomenology [37], the thermodynamic properties [38,39] etc. However, despite this extended research, there are still many ambiguities if Hořava-Lifshitz gravity is reliable and capable of a successful description of the gravitational background of our world, as well as of the cosmological behavior of the universe [5-7, 11, 40, 41].…”

Generalized second law of thermodynamics for non-canonical scalar field model with corrected-entropy

“…Wang et al [27] has found that the first law and GSL of thermodynamics hold on the apparent horizon, but they break down for the event horizon. Till now a lot of work [28][29][30][31][32][33][34][35] has been done where the validity of first law and GSL of thermodynamics on apparent and event horizons have been investigated in various cosmological phenomena.…”