Speaker
Description
In this talk I will review the separate universe framework as a tool to perform loop calculations during and after inflation. I will describe recent work (with L. Iacconi and D. Mulryne) in which we use this framework to calculate loops representing a cascade of power from short scales to much longer, infrared scales. The backreaction associated with this cascade can destroy our ability to uniquely predict the subsequent evolution of a superhorizon volume based on the smoothed field values at its location, which is an essential condition for use of the separate universe method. I will discuss a personal selection of open issues in relating separate-universe type calculations to in-in type calculations using the full formulation of out-of-equilibrium field theory.
