On gravitational preheating

Abstract We consider dark matter production during the inflaton oscillation epoch. It is conceivable that renormalizable interactions between and may be negligible. In this case, leading role played by higher dimensional operators generated gravity thus suppressed Planck scale. focus on dim-6 study corresponding particle in perturbative non-perturbative regimes. find rate dominated non-derivative involving powers of field. Even if they appear with small Wilson coefficients, such can readily account for correct abundance.