Physics (Internal)

Primordial Standard Clocks as a Direct Probe of the Scenario of the Primordial Universe

This event is part of the HET Seminar Series.

How to observationally distinguish the inflation scenario from alternatives to inflation model-independently is an important challenge in modern astrophysics and 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, excited by the extreme high energy of the primordial universe.