Particle production during inflation, the role of quantum coherence

by Kimmo Juhani Kainulainen (University of Jyvaskyla (FI))

Wednesday 11 Nov 2026, 11:30 → 12:30 Europe/Zurich

4/2-011 - TH common room (CERN)

I will discuss a the (dark matter) particle production during and after the inflation in a spectator scalar field model with a non-minimal coupling to gravity. Due to the non-minimal coupling the scalar gets a time-dependent, oscillating effective mass term that can give rise to both a tachyonic instability and a parametric resonance. Our main interest is in quantifying the role of the quantum coherence in these processes, wherefore we derive quantum kinetic equations (QKE's) for the model using 2PI-formalism. I present (within limits of using the blackboard) some results based on the Hartree approximation and compare them with COSMOLATTICE simulations. In the end I show how one can extend the QKE's to include the mode mixing collision integrals, which are the key element missing in the Hartree level QKE's.