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Density perturbations in the Ekpyrotic Universe and string-inspired generalizations

Shinji Tsujikawa
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Abstract

We study density perturbations in several cosmological models motivated by string theory. The evolution and the spectra of curvature perturbations ${\cal R}$ are analyzed in the Ekpyrotic scenario and nonsingular string cosmologies. We find that these string-inspired models generally exhibit blue spectra in contrast to standard slow-roll inflationary scenarios. We also clarify the parameter range where ${\cal R}$ is enhanced on superhorizon scales.

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Shinji Tsujikawa. 2001-12-31. Density perturbations in the Ekpyrotic Universe and string-inspired generalizations. https://doi.org/10.1016/s0370-2693(01)01526-x

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