KIPAC Tea Talk: Constraining Inflation with the CMB: From Cosmological Colliders to Open Quantum Systems

Abstract: The Cosmic Microwave Background (CMB) offers a unique window into an extremely high-energy physics of the early universe. While the standard paradigm of single-field inflation successfully explains the origin of primordial fluctuations, the exact particle physics driving this epoch remains unknown. In this talk, I will demonstrate how higher-order CMB statistics connects high-energy theory with cosmological observations. First, I will discuss the cosmological collider program, where heavy fields present during inflation leave distinct, oscillatory imprints on primordial non-Gaussianities. I will present recent work translating these theoretical signatures into concrete observational constraints on the mass and spin of new particles in the early universe. Second, I will approach inflation from the perspective of open quantum systems. Within the framework of an Open Effective Field Theory of Inflation, we can model dissipative inflation, wherein the inflatoin interacts with an environmental bath. I will highlight recent and ongoing work that jointly utilizes the CMB power spectrum and bispectrum to place robust constraints on these dissipative dynamics. Ultimately, this seminar will illustrate how precision cosmological data can be used to constrain the parameter space of complex inflationary models and probe fundamental physics at energy scales far beyond the reach of terrestrial accelerators.