Infrared Issues in de Sitter Space: Secular Growth of Fluctuations and the Breakdown of the Semiclassical Approximation.

          @misc{ scivideos_PIRSA:10060015,
            doi = {10.48660/10060015},
            url = {https://pirsa.org/10060015},
            author = {Holman, Richard},
            keywords = {Cosmology},
            language = {en},
            title = {Infrared Issues in de Sitter Space: Secular Growth of Fluctuations and the Breakdown of the Semiclassical Approximation.},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2010},
            month = {jun},
            note = {PIRSA:10060015 see, \url{https://scivideos.org/pirsa/10060015}}
          }
          

Abstract

I'll discuss some work done in collaboration with Cliff Burgess, Louis Leblond and Sarah Shandera on the significance of the IR divergences in de Sitter space. First, I'll talk about how large fluctuations at long distances can induce the failure of the loop expansion for interacting field theories with massless degrees of freedom in de Sitter space, much in the same manner as happens in thermal field theories. Then I'll shift gears slightly and describe work involving the use of the dynamical renormalization group in resumming the secularly growing perturbative corrections to correlation functions for massless, minimally coupled scalar fields in de Sitter.