Speaker
Yuko Urakawa
(KEK)
Description
The gradient expansion and the separate universe approach provide an effective description of inflationary soft modes after coarse-graining shorter-wavelength degrees of freedom. We formulate a locality condition on the quantum state that validates this effective description. The same condition also implies a generalized soft theorem, from which the standard consistency relations follow under additional assumptions, and ensures infrared regularity of correlators invariant under large gauge transformations. I will also briefly discuss an analysis beyond the gradient expansion based on classical lattice simulations and its applications.