Non-minimal gravitational reheating during kination

Understand

A new mechanism is presented which can reheat the Universe in non-oscillatory models of inflation, where the inflation period is followed by a period dominated by the kinetic density for the inflaton field (kination).

• The mechanism considers an auxiliary field non-minimally coupled to gravity.
• The auxiliary field is a spectator during inflation, rendered heavy by the non-minimal coupling to gravity.
• During kination however, the non-minimal coupling generates a tachyonic mass, which displaces the field, until its bare mass becomes important, leading to coherent oscillations.