3:30–4:30 pm ERC 161
From Large to Small: Symmetries and the Origins of Structure in the Universe
What was the universe like in its first moments? Remarkably, we can gain insight into the infancy of universe by looking at the largest scales today, using subtle correlations imprinted at very early times. This striking connection between the very large the very small is an opportunity to use cosmological observations to probe high energies, and also to bring modern theoretical tools to bear on the deep questions that cosmology presents us with. I will discuss recent progress in both directions, highlighting the power of effective field theory and symmetries as guiding principles. As an example, I will explain how the symmetry-oriented viewpoint can help unravel the origins of structure in the universe by enabling us to derive powerful model-independent tests of the simplest inflationary paradigm. Violations of these relations can signal the presence of new heavy particles, allowing us to use the primordial universe as the highest-energy particle accelerator. I will also describe recent theoretical advances in understanding the signatures of these heavy particles, and will explain how these advances could help shed light on fundamental questions, like the emergence of time in cosmology.