Dynamical and observational constraints on the Warm Little Inflaton
  scenario
  We explore the dynamics and observational predictions of the Warm Little
Inflaton scenario, presently the simplest realization of warm inflation within
a concrete quantum field theory construction. We consider three distinct types
of scalar potentials for the inflaton, namely chaotic inflation with a quartic
monomial potential, a Higgs-like symmetry breaking potential and a
non-renormalizable plateau-like potential. In each case, we determine the
parametric regimes in which the dynamical evolution is consistent for 50-60
e-folds of inflation, taking into account thermal corrections to the scalar
potential and requiring, in particular, that the two fermions coupled directly
to the inflaton remain relativistic and close to thermal equilibrium throughout
the slow-roll regime and that the temperature is always below the underlying
gauge symmetry breaking scale. We then compute the properties of the primordial
spectrum of scalar curvature perturbations and the tensor-to-scalar ratio in
the allowed parametric regions and compare them with Planck data, showing that
this scenario is theoretically and observationally successful for a broad range
of parameter values.
