Slavnov-Taylor Identities for Primordial Perturbations – Lasha Berezhiani

Date: Tue. October 8th, 2013, 11:30 am-12:30 pm
Location: Rockefeller 221

I will show that all consistency relations for the primordial perturbations derive from a single, master identity, which follows from the Slavnov-Taylor identity for spatial diffeomorphisms. This master identity is valid at any value of momenta and therefore goes beyond the soft limit. This approach underscores the role of spatial diffeomorphism invariance at the root of cosmological consistency relations. It also offers new insights on the necessary conditions for their validity: a physical contribution to the vertex functional must satisfy certain analyticity properties in the soft limit in order for the consistency relations to hold. For standard inflationary models, this is equivalent to requiring that mode functions have constant growing-mode solutions. For more exotic models in which modes do not “freeze” in the usual sense, the analyticity requirement offers an unambiguous criterion.