Cosmological density perturbations from perturbed couplings

Shinji Tsujikawa*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


The density perturbations generated when the inflaton decay rate is perturbed by a light scalar field χ are studied. By explicitly solving the perturbation equations for the system of two scalar fields and radiation, we show that even in low energy-scale inflation nearly scale-invariant spectra of scalar perturbations with an amplitude set by observations are obtained through the conversion of χ fluctuations into adiabatic density perturbations. We demonstrate that the spectra depend on the average decay rate of the inflaton and on the inflaton fluctuations. We then apply this new mechanism to string cosmologies and generalized Einstein theories and discuss the conditions under which scale-invariant spectra are possible.

Original languageEnglish
Article number083510
JournalPhysical Review D
Issue number8
Publication statusPublished - 2003
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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