695 citations · 2.3k across the 22 of their papers we have counts for
14 papers · 1 filter
Generalised perturbation equations in bouncing cosmologies
Antonio Cardoso, David Wands
We consider linear perturbation equations for long-wavelength scalar metric perturbations in generalised gravity, applicable to non-singular cosmological models including a bounce…
Non-Gaussianities from ekpyrotic collapse with multiple fields
Kazuya Koyama, Shuntaro Mizuno, Filippo Vernizzi +1
We compute the non-Gaussianity of the curvature perturbation generated by ekpyrotic collapse with multiple fields. The transition from the multi-field scaling solution to a single-…
Diagrammatic approach to non-Gaussianity from inflation
Christian T. Byrnes, Kazuya Koyama, Misao Sasaki +1
We present Feynman type diagrams for calculating the n-point function of the primordial curvature perturbation in terms of scalar field perturbations during inflation. The diagrams…
Curvature perturbations from ekpyrotic collapse with multiple fields
Kazuya Koyama, Shuntaro Mizuno, David Wands
A scale-invariant spectrum of isocurvature perturbations is generated during collapse in the ekpyrotic scaling solution in models where multiple fields have steep negative exponent…
Coupled bulk and brane fields about a de Sitter brane
Antonio Cardoso, Kazuya Koyama, Andrew Mennim +2
We consider the evolution of a bulk scalar field in anti-de Sitter (AdS) spacetime linearly coupled to a scalar field on a de Sitter boundary brane. We present results of a spectra…
Low-energy effective theory for a Randall-Sundrum scenario with a moving bulk brane
Ludovica Cotta-Ramusino, David Wands
We derive the low-energy effective theory of gravity for a generalized Randall-Sundrum scenario, allowing for a third self-gravitating brane to live in the 5D bulk spacetime. At ze…