Hydro+ in Action: Understanding the Out-of-Equilibrium Dynamics Near a Critical Point in the QCD Phase Diagram

Understand

Upcoming experimental programs will look for signatures of a possible critical point in the QCD phase diagram in fluctuation observables.

• To understand and predict these signatures, one must account for the fact that the dynamics of any critical fluctuations must be out-of-equilibrium: because of critical slowing down, the fluctuations cannot stay in equilibrium as the droplet of QGP produced in a collision expands and cools.
• Furthermore, their out-of-equilibrium dynamics must also influence the hydrodynamic evolution of the cooling droplet.
• The recently developed Hydro+ formalism allows for a consistent description of both the hydrodynamics and the out-of-equilibrium fluctuations, including the feedback between them.