  Effective field theories (EFTs) of heavy particles coupled to the inflaton
are rife with operator redundancies, frequently obscured by sensitivity to both
boundary terms and field redefinitions. We initiate a systematic study of these
redundancies by establishing a minimal operator basis for an archetypal
example, the abelian gauge-Higgs-inflaton EFT. Working up to dimension 9, we
show that certain low-dimensional operators are entirely redundant and identify
new non-redundant operators with potentially interesting cosmological collider
signals. Our methods generalize straightforwardly to other EFTs of heavy
particles coupled to the inflaton.
