Understand
This article reviews basic construction and cosmological implications of a power-counting renormalizable theory of gravitation recently proposed by Horava.
- We explain that (i) at low energy this theory does not exactly recover general relativity but instead mimic general relativity plus dark matter; that (ii) higher spatial curvature terms allow bouncing and cyclic universes as regular solutions; and that (iii) the anisotropic scaling with the dynamical critical exponent z=3 solves the horizon problem and leads to scale-invariant cosmological perturbations even without inflation.
- We also comment on issues related to an extra scalar degree of freedom called scalar graviton.
- In particular, for spherically-symmetric, static, vacuum configurations we prove non-perturbative continuity of the lambda->1+0 limit, where lambda is a parameter in the kinetic action and general relativity has the value lambda=1.
Reading the bibliography…