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Title: Cosmological perturbations across an S-brane

Space-filling S-branes can mediate a transition between a contracting and an expanding universe in the Einstein frame. Following up on previous work that uncovered such bouncing solutions in the context of weakly coupled thermal configurations of a certain class of type II superstrings, we set up here the formalism in which we can study the evolution of metric fluctuations across such an S-brane. Our work shows that the specific nature of the S-brane, which is sourced by non-trivial massless thermal string states and appears when the universe reaches a maximal critical temperature, allows for a scale invariant spectrum of curvature fluctuations to manifest at late times via a stringy realization of the matter bounce scenario. The finite energy density at the transition from contraction to expansion provides calculational control over the propagation of the curvature perturbations through the bounce, furnishing a working proof of concept that such a stringy universe can result in viable late time cosmology.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Department of Physics, McGill University, Montréal, QC, H3A 2T8 (Canada)
  2. Laboratoire de Physique Théorique, Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris cedex 05 (France)
  3. Centre de Physique Théorique, Ecole Polytechnique, F-91128 Palaiseau cedex (France)
  4. Theory Division, PH-TH Case C01600, CERN, CH-1211 Geneva (Switzerland)
  5. Department of Physics, University of Cyprus, Nicosia 1678 (Cyprus)
Publication Date:
OSTI Identifier:
22370659
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 03; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRANES; COSMOLOGY; CRITICAL TEMPERATURE; ENERGY DENSITY; EVOLUTION; PERTURBATION THEORY; SUPERSTRING MODELS; UNIVERSE