The Physical Squeezed Limit: Consistency Relations at Order q^2
  In single-field models of inflation the effect of a long mode with momentum q
reduces to a diffeomorphism at zeroth and first order in q. This gives the
well-known consistency relations for the n-point functions. At order q^2 the
long mode has a physical effect on the short ones, since it induces curvature,
and we expect that this effect is the same as being in a curved FRW universe.
In this paper we verify this intuition in various examples of the three-point
function, whose behaviour at order q^2 can be written in terms of the power
spectrum in a curved universe. This gives a simple alternative understanding of
the level of non-Gaussianity in single-field models. Non-Gaussianity is always
parametrically enhanced when modes freeze at a physical scale k_{ph, f} shorter
than H: f_{NL} \sim (k_{ph, f}/H)^2.
