FTheory: The Separate Universe Approach to Soft Limits
In this talk I'll calculate soft limits of n-point inflationary correlation functions using separate universe techniques. Our approach naturally allows for multiple fields an leads to an elegant diagrammatic approach. We apply this to the bispectrum and trispectrum, giving explicit formulae for all possible single- and double-soft limits. When compared to previous work on the bispectrum, we find a 20% theoretical correction to observable parameters relevant for future cosmological experiments. We also investigate consistency relations and present an infinite tower of inequalities between soft correlation functions which generalize the Suyama-Yamaguchi inequality.