Generation of the Higgs Condensate and Its Decay after Inflation
  We investigate the dynamics of the Standard Model higgs with a minimal
coupling to gravity during and after inflation. In the regime where the
Standard Model vacuum is stable, we find that the higgs becomes a light
spectator field after about 30 efolds of inflation, irrespectively of its
initial value. Once the higgs has become light, its root-mean-square value h_*
relaxes to equilibrium in about 85 efolds for the inflationary scale of
H_*=10^4 GeV and in 20 efolds for H_*=10^10 GeV. The equilibrium value is given
by h_*~0.36 lambda^{-1/4}H_*, where lambda=0.09 ... 0.0005 is the higgs self
coupling at the scales H_*=10^4 ... 10^10 GeV. We show that the main decay
channel of the higgs condensate after inflation is the resonant production of
Standard Model gauge bosons. For a set of parameters we find that a significant
part of the condensate has decayed in between 340 and 630 Hubble times after
the onset of higgs oscillations, depending on H_* in a non-trivial way. The
higgs perturbations correspond to isocurvature modes during inflation but they
could generate significant adiabatic perturbations at a later stage for example
through a modulation of the reheating stage. However, this requires that the
inflaton(s) decay no later than a few hundred Hubble times after the onset of
higgs oscillations.
