Hořava gravity at a Lifshitz point: A progress report
Abstract
Hořava’s quantum gravity at a Lifshitz point is a theory intended to quantize gravity by using traditional quantum field theories. To avoid Ostrogradsky’s ghosts, a problem that has been facing in quantization of general relativity since the middle of 1970’s, Hořava chose to break the Lorentz invariance by a Lifshitztype of anisotropic scaling between space and time at the ultrahigh energy, while recovering (approximately) the invariance at low energies. With the stringent observational constraints and selfconsistency, it turns out that this is not an easy task, and various modifications have been proposed, since the first incarnation of the theory in 2009. In this review, we shall provide a progress report on the recent development of Hořava gravity. In particular, we first present four so far moststudied versions of Hořava gravity, by focusing first on their selfconsistency and then their consistency with experiments, including the solar system tests and cosmological observations. Then, we provide a general review on the recent development of the theory in three different but also related areas: (i) universal horizons, black holes and their thermodynamics, (ii) nonrelativistic gauge/gravity duality and (iii) quantization of the theory. The studies in these areas can be easily generalized to other gravitational theories with broken Lorentz invariance.
 Publication:

International Journal of Modern Physics D
 Pub Date:
 2017
 DOI:
 10.1142/S0218271817300142
 arXiv:
 arXiv:1701.06087
 Bibcode:
 2017IJMPD..2630014W
 Keywords:

 Quantum gravity;
 universal horizons;
 Hawking radiation;
 nonrelativistic gauge/gravity duality;
 04.60.m;
 04.70.s;
 97.60.Lf;
 98.80.k;
 Quantum gravity;
 Physics of black holes;
 Black holes;
 Cosmology;
 General Relativity and Quantum Cosmology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 revtex4, three figures. Corrected various typos. Int. J. Mod. Phys. D26 (2017) 1730014