4 papers
On graviton production in braneworld cosmology
Cyril Cartier, Ruth Durrer, Marcus Ruser
We study braneworlds in a five dimensional bulk, where cosmological expansion is mimicked by motion through AdS. We show that the five dimensional graviton reduces to the four…
Tachyonic perturbations in AdS orbifolds
Cyril Cartier, Ruth Durrer
We show that scalar as well as vector and tensor metric perturbations in the Randall-Sundrum II braneworld allow normalizable tachyonic modes, i.e., possible instabilities. These i…
Scalar perturbations in an -regularised cosmological bounce
Cyril Cartier
We consider the evolution of scalar perturbations in a class of non-singular bouncing universes obtained with higher-order corrections to the low-energy bosonic string action. We s…
Cosmological perturbations and the transition from contraction to expansion
C. Cartier, R. Durrer, E. J. Copeland
We investigate both analytically and numerically the evolution of scalar perturbations generated in models which exhibit a smooth transition from a contracting to an expanding Frie…