Comment on "Density perturbations in the ekpyrotic scenario"
High Energy Physics - Theory
2009-11-07 v2 Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Abstract
In the paper ``Density perturbations in the ekpyrotic scenario'', it is argued that the expected spectrum of primordial perturbations should be scale invariant in this scenario. Here we show that, contrary to what is claimed in that paper, the expected spectrum depends on an arbitrary choice of matching variable. As no underlying (microphysical) principle exists at the present time that could lift the arbitrariness, we conclude that the ekpyrotic scenario is not yet a predictive model.
Cite
@article{arxiv.hep-th/0204222,
title = {Comment on "Density perturbations in the ekpyrotic scenario"},
author = {Jerome Martin and Patrick Peter and Nelson Pinto-Neto and Dominik J. Schwarz},
journal= {arXiv preprint arXiv:hep-th/0204222},
year = {2009}
}
Comments
4 pages, no figure, RevTeX, commenting on hep-th/0109050