Unified description of corpuscular and fuzzy bosonic dark matter

Abstract: We derive from first principles equations for bosonic, non-relativistic and self-interacting dark matter which can include both a condensed, low momentum "fuzzy" component and one with higher momenta that may be approximated as a collection of particles. The resulting coupled equations consist of a modified Gross-Pitaevskii equation describing the condensate and a kinetic equation describing the higher momentum modes, the "particles", along with the Poisson equation for the gravitational potential sourced by the density of both components. Our derivation utilizes the Schwinger-Keldysh path integral formalism and applies a semi-classical approximation which can also accommodate collisional terms amongst the particles and between the particles and the condensate to second order in the self-coupling strength. The equations can therefore describe both CDM and Fuzzy Dark Matter in a unified way, allowing for the coexistence of both phases and the inclusion of quartic self-interactions.