Title: Primordial Standard Clocks as a Direct Probe of the Scenario of the Primordial Universe
Speaker: Xingang Chen, Harvard University
Abstract: How to model-independently distinguish the inflation scenario from alternatives to inflation is an important challenge in modern cosmology. In this talk, we show that massive fields in the primordial universe can function as standard clocks and imprint clock signals in the density perturbations that directly record the scale factor of the universe as a function of time, a(t). This function is the defining property of any primordial universe scenario, so can be used to falsify competing scenarios in a model-independent fashion. The signals also encode the mass and spin spectra of the particle physics at the extreme high energy scale of the primordial universe.