We derive coupled equations for self-interacting scalar dark matter, which can include both a condensed, low momentum ''fuzzy'' component and one with higher momenta that may be described as a collection of classical particles. We do this from first principles, using the Schwinger-Keldysh path integral and the corresponding Feynman diagrams in a perturbative expansion. The resulting coupled...
False vacuum decay (FVD) plays a vital role in many models of the early Universe, with important implications for inflation, the electroweak vacuum, and gravitational waves. However, it is also a highly non-perturbative and non-equilibrium process which is challenging to model theoretically, with existing Euclidean methods relying on numerous assumptions that have yet to be empirically...
