Near scale invariance with modified dispersion relations

C. Armendariz-Picon

Research output: Contribution to journalReview articlepeer-review

31 Scopus citations

Abstract

We describe a novel mechanism for generating a nearly scale invariant spectrum of adiabatic perturbations during a non-inflationary stage. It relies on a modified dispersion relation that contains higher powers of the spatial momentum of matter perturbations. This dispersion relation leads to the superluminal speeds required to seed a spectrum of super-horizon perturbations (we also explain why superluminal velocities are not a problem in this setting). We implement our mechanism in the context of a massless scalar field in an otherwise perfectly homogeneous universe. The couplings of the field to background scalars and tensors give rise to the required modification of its dispersion relation, and the couplings of the scalar to matter result in an adiabatic primordial spectrum. This work is meant to explicitly illustrate that it is possible to seed nearly scale invariant primordial spectra without inflation, within a conventional expansion history.

Original languageEnglish (US)
Article number010
JournalJournal of Cosmology and Astroparticle Physics
Issue number10
DOIs
StatePublished - Oct 1 2006

Keywords

  • Cosmological perturbation theory
  • Inflation
  • Physics of the early universe
  • Quantum field theory on curved space

ASJC Scopus subject areas

  • Astronomy and Astrophysics

Fingerprint Dive into the research topics of 'Near scale invariance with modified dispersion relations'. Together they form a unique fingerprint.

Cite this