Constant-Roll Inflation

Abstract

Constant-roll inflation is a distinctive class of phenomenological inflationary models in which the inflaton's rate of roll remains constant. It provides an exact solution that is compatible with the latest observational constraints and offers a natural framework for enhancing the curvature power spectrum, which is relevant to the formation of primordial black holes. In this paper, I review constant-roll inflation in memory of Alexei Starobinsky.

arXiv comment23 pages, 6 figures. Invited contribution in "Open Issues in Gravitation and Cosmology: Original Contributions, Essays, and Recollections in Honor of Alexei Starobinsky", Andrei Barvinsky and Alexander Kamenshchik (eds.), Fundamental Theories of Physics, vol. 225, Springer (2026). v2: Corrected typos and updated figure captions to match the published version