Goldstone bosons and a dynamical Higgs field

Understand

Higgs inflation uses the gauge variant Higgs field as the inflaton.

• During inflation the Higgs field is displaced from its minimum, which results in associated Goldstone bosons that are apparently massive.
• Working in a minimally coupled U(1) toy model, we use the closed-time-path formalism to show that these Goldstone bosons do contribute to the one-loop effective action.
• Therefore the computation in unitary gauge gives incorrect results.