Distinctive signatures of space-time diffeomorphism breaking in EFT of
  inflation
  The effective field theory of inflation is a powerful tool for obtaining
model independent predictions common to large classes of inflationary models.
It requires only information about the symmetries broken during the
inflationary era, and on the number and nature of fields that drive inflation.
In this paper, we consider the case for scenarios that simultaneously break
time reparameterization and spatial diffeomorphisms during inflation. We
examine how to analyse such systems using an effective field theory approach,
and we discuss several observational consequences for the statistics of scalar
and tensor modes. For example, examining the three point functions, we show
that this symmetry breaking pattern can lead to an enhanced amplitude for the
squeezed bispectra, and to a distinctive angular dependence between their three
wavevectors. We also discuss how our results indicate prospects for
constraining the level of spatial diffeomorphism breaking during inflation.
