Preheating and Reheating after Standard Inflation
  We study the two-phase scenario following inflation, where the initial step
is preheating, accompanied by a step of perturbative reheating at which
inflaton field decays transferring all of its energy to create relativistic
particles, the interaction of these particles will evolve towards a state of
thermal equilibrium with a temperature Tre called the reheating temperature. It
is observed that the scenario of reheating normally predicts the maximum
reheating temperature that corresponds to an almost instantaneous transition
from inflation to the radiation domination era. This will naturally lead to a
nonperturbative preheating. In this framework, we propose constraints on the
reheating duration parameters expressed in terms of the cosmic microwave
background (CMB) inflationary scalar spectral index. In this work, we study the
compatibility of polynomial and Higgs models of inflation with the
observational data obtained from Planck 2018.
