TAPIR Special Seminar

In the current era of precision cosmology, the Universe on large scales has become a unique probe of many fundamental physics questions that are hard or even impossible to address with conventional terrestrial experiments. In this seminar, I will discuss examples of what this "Cosmic Laboratory" teaches us about neutrino physics, dark matter, dark energy and inflation. The main focus will be on how deep insights into the physics of inflation can be obtained by using galaxy clustering on extremely large scales to study non-Gaussianity of the primordial density fluctuations. I will explain what it would take for a galaxy survey to use this primordial non-Gaussianity signal to distinguish between single- and multi-field inflation and I will conclude by introducing a specific proposal for such a survey: SPHEREx, a Caltech/JPL centered mission which has recently been selected for phase A study under NASA's SMEX program.