HET seminar: John Joseph Carrasco
Speaker: John Joseph Carrasco
Title: Some lessons from the universe’s *largest* effective field theory.
Abstract: Large Scale Structure (LSS) surveys promise to become the next leading cosmological probe. While simulation is an important and powerful tool (especially at non-linear and shorter scales), we should aspire to develop complementary analytic techniques for precise predictions at large scales. Formal theorists and phenomenologists, working on problems from nuclear to Planck scales, have long recognized the power of effective field theories (EFTs) to allow us to concentrate only on the most important dynamics at a given scale, parameterizing away our ignorance of less impactful details. Fascinatingly, stochastically-sourced classical field theories invite us to apply many familiar ideas to open problems in precision cosmology. I will give a gentle and broadly physical introduction to the setup of an EFT of LSS, and close with a discussion of a recent promising calculation approach: decomposing phenomenologically relevant loop-level Lambda-CDM predictions in terms of much simpler power-law universes — formally equivalent to integrals encountered in massless quantum field theory. C.f. arXiv:1708.08130 and references therein (esp. 1206.2926 , 1304.4946 , 1310.0464 ).