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The primordial curvature perturbation in the ekpyrotic universe.

Research output: Contribution to journalJournal article

<mark>Journal publication date</mark>3/01/2002
<mark>Journal</mark>Physics Letters B
Issue number1-2
Number of pages4
Pages (from-to)1-4
<mark>Original language</mark>English


In the ekpyrotic scenario the Universe is initially collapsing, the energy density coming from a scalar field with a negative exponential potential. On the basis of a calculation ignoring the gravitational back-reaction the authors of the scenario claim that during collapse the vacuum fluctuation creates a perturbation in the comoving curvature, which has a flat spectrum in accordance with observation. In this Letter the back-reaction is included, and it is found that the spectrum during collapse is strongly scale-dependent with negligible magnitude.

Bibliographic note

The ekpyrotic scenario is an alternative to the standard inflation scenario. In this paper it was shown that the predictions have ambiguities that were not recognised by the authors. The paper sparked an influential and on-going debate about the ekpyrotic scenario. 109 citations (SPIRES). RAE_import_type : Journal article RAE_uoa_type : Physics