Superhorizon curvature perturbation in ultraslow-roll inflation

Shu Lin Cheng, Wolung Lee, Kin Wang Ng

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


We study the growth of superhorizon modes in the curvature perturbation during an ultraslow-roll or a large-η phase in single-field inflation. In a simple toy model, we derive the two-point correlation function of the curvature perturbation and show that the requirement for causality restricts the growth rate and hence puts a lower limit on the value of η. The toy model is then realized by considering an inflation potential with an inflection point. Our study is useful to assessing the growth of the curvature perturbation that seeds the formation of primordial black holes.

Original languageEnglish
Article number063524
JournalPhysical Review D
Issue number6
Publication statusPublished - 2019 Mar 15

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


Dive into the research topics of 'Superhorizon curvature perturbation in ultraslow-roll inflation'. Together they form a unique fingerprint.

Cite this