NBIA Gravity Seminar: Sofie Koksbang

Speaker: Sofie Koksbang

Title: Observational effects of cosmic backreaction with concrete abstract cosmology and machine learning

Abstract: Cosmic backreaction is a concept from inhomogeneous cosmology which originally gained attention because the phenomenon can lead to apparent accelerated expansion of the universe without dark energy. However, it is at this point unclear to what extent cosmic backreaction is relevant for our universe. One of the methods for revealing its importance (or lack thereof) is using observational tests that can either reveal a deviation from FLRW behavior or directly reveal effects of cosmic backreaction.

 In this talk, I will give a brief review of cosmic backreaction. I will then introduce "concrete abstract cosmology" and discuss the observational signatures of backreaction that have been uncovered with this approach and what possibilities the approach gives when combined with machine learning.