Gravitational reheating

Our present understanding of the reheating phase is incomplete due to a lack observations. Apart from its cosmological implications, should play vital role in particle physics and inflation model building. Conventionally, dynamics are modeled by invoking arbitrary coupling among inflaton daughter fields. Such an approach lacks robust predictions, couplings, difficult verify through observation. In this paper, we propose minimal scenario, where coupled with all fields only gravitationally. Besides being successful Universe, scenario offers strong prediction primordial gravitational wave spectrum discards large number possible models dark matter that otherwise consistent Planck.