Primordial perturbations and inflation in holographic cosmology

Abstract

We consider an inflationary scenario in the holographic braneworld with a cosmological fluid occupying the 3+1 dimensional brane located at the holographic boundary of an asymptotic ADS${}_5$ bulk. The contribution of the boundary conformal field can be represented as a modification of Einstein's equations on the boundary. Using these effective Einstein equations we calculate the cosmological perturbations and derive the corresponding power spectra assuming a general $k$-essence type of inflaton. We find that the braneworld scenario affects the scalar power spectrum only in the speed of sound dependence on the slow-roll parameters whereas there is no change in the tensor power spectrum. This implies that the changes in the spectral indices appear at the second order in the slow-roll parameter expansion.

20 pages, 1 figure. The field equations are corrected by adding a new term which vanishes for a conformally flat background metric. The resulting change of perturbed field equations does not affect the results and conclusions. The corrections match the Erratum published in PRD

References in corpus (5)

• New Test of the Gravitational $1/r^2$ Law at Separations down to 52 $\mu$m
• Primordial black holes and secondary gravitational waves from k/G inflation
• Universality classes for models of inflation
• A note on the equivalence of a barotropic perfect fluid with a K-essence scalar field
• A note on perfect scalar fields

Cited by in corpus (5)

• A scaling invariance of the perturbations in $k$-inflation models
• Constant-roll inflation with tachyon field in the holographic braneworld
• Primordial perturbations and inflation in a holography inspired Gauss-Bonnet cosmology
• Scale-dependent gravity and covariant scale-setting
• Primordial black hole formation in k-inflation models