Remote Nordic HET seminar: Robert Rosati
Speaker: Robert Rosati
Title: Rapid-turn inflation in supergravity is rare and tachyonic
Abstract: Understanding viable models of inflation in supergravity has long been a goal of theoretical cosmology. Single-field supergravity inflation has historically been plagued by the eta-problem, where the inflaton’s tachyonic mass destabilizes the inflationary trajectory. Allowing additional fields can avoid this problem if the inflationary trajectory turns rapidly in field space -- tachyons no longer have a destabilizing effect. In this talk I will discuss our recent work on these rapid-turn supergravity inflation models, with a particular emphasis on axion inflation. We find a large class of supergravity models that support rapid-turn inflation, but with a highly-curved field space that would make string realizations difficult. We exhaustively search several multi-field supergravity models from the literature and our own construction and find all rapid-turn trajectories to come from the same mechanism, and with high field space curvature. Time permitting I will also discuss some follow-up work on rapid-turning inflationary trajectories which may help understand the relationship between the structure of field space and turning.