The inflationary paradigm has been very successful in explaining the observed spatial geometry and (in)homogeneity of our Universe. Despite this, we still don’t understand how inflation fits into our particle physics models: we don’t know the nature of the inflaton or its couplings to the Standard Model, for example. This embedding of inflation within QFT can lead to very complicated models, with a large number of fields and interactions. When this number is sufficiently large, one could expect that cosmological observables and parameters, such as the power spectrum and its tilt, or the reheating temperature, arise as expectation values of an effective stochastic description of the complex microscopic dynamics. Remarkably, there is a mathematical equivalence between stochastic particle production in cosmology and electron transport in wires. With M. Amin and his students/collaborators, we attempt to exploit this equivalence and determine if an universal behavior emerges in the evolution of the particle occupation numbers in systems with a large number of scatterings and statistically inequivalent interacting fields.
Our first paper (in Minkowski space) has been published as
M. A. Amin, M. A. G. Garcia, H. Y. Xie and O. Wen, Multifield Stochastic Particle Production: Beyond a Maximum Entropy Ansatz, JCAP 1709, 015 (2017)