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Generating the curvature perturbation without an inflation.

Research output: Contribution to journalJournal article

Published
<mark>Journal publication date</mark>3/01/2002
<mark>Journal</mark>Physics Letters B
Issue number1-2
Volume524
Number of pages10
Pages (from-to)5-14
<mark>State</mark>Published
<mark>Original language</mark>English

Abstract

We present a mechanism for the origin of the large-scale curvature perturbation in our Universe by the late decay of a massive scalar field, the curvaton. The curvaton is light during a period of cosmological inflation, when it acquires a perturbation with an almost scale-invariant spectrum. This corresponds initially to an isocurvature density perturbation, which generates the curvature perturbation after inflation when the curvaton density becomes a significant fraction of the total. The isocurvature density perturbation disappears if the curvaton completely decays into thermalised radiation. Any residual isocurvature perturbation is 100% correlated with the curvature. The same mechanism can also generate the curvature perturbation in pre-big bang/ekpyrotic models, provided that the curvaton has a suitable non-canonical kinetic term so as to generate a flat spectrum.

Bibliographic note

This agenda-setting paper proposed a radical modification of the inflationary scenario, whereby the field responsible for the origin of structure in the universe may lie dormant until a rather late epoch. This 'curvaton' mechanism opened the way to new ways of thinking about the early universe. 353 citations (SPIRES). RAE_import_type : Journal article RAE_uoa_type : Physics