Diffusion and two-particle correlations

Abstract

Fluctuation signals of the QCD phase transition in nuclear collisions can be dissipated due to diffusion. Diffusive modes in the standard formulation of relativistic hydrodynamics propagate with infinite speed, violating causality. We develop a causal diffusion equation study the dissipation of net-charge fluctuations. We find that causality restricts the extent to which diffusion can dissipate these fluctuations.