Cosmological perturbations in Horava-Lifshitz theory without detailed balance

Scale-invariant cosmological perturbations from Hořava-Lifshitz gravity without inflation

Based on the renormalizable theory of gravitation recently proposed by Hořava, we present a simple scenario to generate almost scale-invariant, super-horizon curvature perturbations. The anisotropic scaling with dynamical critical exponent z = 3 implies that the amplitude of quantum fluctuations of a free scalar field generated in the early epoch of the expanding universe is insensitive to the ...

Detailed balance in Hǒrava–Lifshitz gravity

We study Hořava–Lifshitz gravity in the presence of a scalar field. When the detailed balance condition is implemented, a new term in the gravitational sector is added in order to maintain ultraviolet stability. The four-dimensional theory is of scalar-tensor type with a positive cosmological constant and gravity is non-minimally coupled with the scalar and its gradient terms. The scalar field ...

Horava-Lifshitz theory as a fermionic aether in Ashtekar gravity

Cosmological Perturbations and Non-Gaussianities in Hořava-Lifshitz Gravity

We investigate cosmological perturbations and non-gaussianities in Hořava-Lifshitz theory of gravitation. In the UV limit, the scalar perturbation in Hořava theory is naturally scale-invariant, ignoring the details of the expansion of the universe. Thus one may relax the exponential inflation and the slow-roll conditions for the inflaton field. Moreover, in the absence of slow-roll conditions, ...

Towards constraining of the Horava-Lifshitz gravities

Recently a renormalizable model of gravity has been proposed, which may be a UV completion of General Relativity (GR) or its infra-red modification. Although a generic vacuum of the theory is anti-de Sitter one, particulars limit of the theory allow for the Minkowski vacuum. In this limit post-Newtonian coefficients coincide with those of the pure General Relativity. Thus the deviations from th...