PU High Energy Theory Seminar

This talk will be held Zoom:
https://princeton.zoom.us/j/97195348538?pwd=bEhjczRmbnNIZjNydFpYQXN0bXZWQT09

Abstract: Dispersion formulas explain how fundamental consistency conditions, such as causality and unitarity, constrain low-energy physical observables. In this talk I will discuss how dispersion formulas in Minkowski, de Sitter, and Anti-de Sitter space are related. In the first part I will discuss the relationship between the recently discovered conformal dispersion formula and the momentum space dispersion formulas originally derived in axiomatic quantum field theory. Specifically, I will argue that the four-point conformal dispersion formula is equivalent to a standard QFT momentum-space dispersion formula applied to a conformal correlation function. In the process, I will discuss possible extensions of the conformal dispersion formula to higher-point functions. In the second part I will explain how perturbative, momentum-space dispersion formulas can be used to simplify the computation of inflationary observables in quasi-dS spacetimes. As an example, I will show how dispersion formulas can be used to find simple expressions for higher-point wavefunction coefficients in the EFT of single-field inflation.