Multifield Stochastic Particle Production: Beyond a Maximum Entropy Ansatz

Understand

We explore non-adiabatic particle production for $N_{\rm f}$ coupled scalar fields in a time-dependent background with stochastically varying effective masses, cross-couplings and intervals between interactions.

• Under the assumption of weak scattering per interaction, we provide a framework for calculating the typical particle production rates after a large number of interactions.
• After setting up the framework, for analytic tractability, we consider interactions (effective masses and cross couplings) characterized by series of Dirac-delta functions in time with amplitudes and locations drawn from different distributions.
• Without assuming that the fields are statistically equivalent, we present closed form results (up to quadratures) for the asymptotic particle production rates for the $N_{\rm f}=1$ and $N_{\rm f}=2$ cases.