A new algorithm for calculating the curvature perturbations in stochastic inflation

Tomohiro Fujita, Masahiro Kawasaki, Yuichiro Tada, Tomohiro Takesako

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


We propose a new approach for calculating the curvature perturbations produced during inflation in the stochastic formalism. In our formalism, the fluctuations of the e-foldings are directly calculated without perturbatively expanding the inflaton field and they are connected to the curvature perturbations by the δN formalism. The result automatically includes the contributions of the higher order perturbations because we solve the equation of motion non-perturbatively. In this paper, we analytically prove that our result (the power spectrum and the nonlinearity parameter) is consistent with the standard result in single field slow-roll inflation. We also describe the algorithm for numerical calculations of the curvature perturbations in more general inflation models.

Original languageEnglish
Article number036
JournalJournal of Cosmology and Astroparticle Physics
Issue number12
Publication statusPublished - 2013 Dec
Externally publishedYes


  • cosmological perturbation theory
  • inflation
  • physics of the early universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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