Hydro Plus In Action

The recently formulated Hydro+ framework describes the interplay between hydrodynamics and out-of-equilibrium long wavelength critical fluctuations in a self-consistent fashion. We present a brief summary of the first simulation of Hydro+ in a simplified model for a heavy ion collision: a boost-invariant fireball undergoing radial flow, see Ref. [1] for details. Within our simplified model, we find three key ingredients of critical dynamics at play: 1) the dynamical fluctuations lag relative to the equilibrium expectation as the fluid cools and flows; 2) the radial flow transports fluctuations by advection; 3) the out-of-equilibrium fluctuations in turn back-react on the bulk evolution.