What can the CMB tell about the microphysics of cosmic reheating?

Understand

In inflationary cosmology, cosmic reheating after inflation sets the initial conditions for the hot big bang.

• We investigate how CMB data can be used to study the effective potential and couplings of the inflaton during reheating and constrain the underlying microphysics.
• If there is a phase of preheating that is driven by a parametric resonance or other instability, then the thermal history and expansion history during the reheating era depend on a large number of microphysical parameters in a complicated way.
• In this case the connection between CMB observables and microphysical parameters can only established with intense numerical studies.