Scalar dark matter production from the inflaton

A curved space-time is known to act as a source for particle production in environments where gravity plays a significant role. We explore this effect in a minimal setup of cosmic inflation on the production of a scalar dark matter candidate during and after the inflationary stage of the universe. We consider the production of dark matter via direct coupling to the inflaton field or from pure gravitational interactions. Cosmological constraints from structure formation and dark matter isocurvature perturbations are discussed. A new analytical expression for the isocurvature power spectrum is provided.