  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. Then, the field
decays into the radiation bath of the hot big bang. The model is generic and
predictive, in that the resulting reheating temperature is a function only of
the model parameters (masses and couplings) and not of initial conditions. It
is shown that reheating can be very efficient also when considering only the
Standard Model.
