Fate of Electroweak Vacuum during Preheating
  Our electroweak vacuum may be metastable in light of the current experimental
data of the Higgs/top quark mass. If this is really the case, high-scale
inflation models require a stabilization mechanism of our vacuum during
inflation. A possible candidate is the Higgs-inflaton/-curvature coupling
because it induces an additional mass term to the Higgs during the slow roll
regime. However, after the inflation, the additional mass term oscillates, and
it can potentially destabilize our electroweak vacuum via production of large
Higgs fluctuations during the inflaton oscillation era. In this paper, we study
whether or not the Higgs-inflaton/-curvature coupling can save our vacuum by
properly taking account of Higgs production during the preheating stage. We put
upper bounds on the Higgs-inflaton/-curvature coupling, and discuss possible
dynamics that might relax them.
