Speaker
Description
Interpreting conserved-charge cumulants near the QCD critical point requires a dynamical description of how fluctuations evolve during the finite lifetime of the fireball. In this talk, I will focus on the conserved-charge diffusion sector and ask how non-Gaussian cumulants are modified when the diffusive current is allowed to retain memory, instead of being instantaneously slaved to the density gradient as in Fick’s law. This is motivated by the fact that, in an evolving medium, gradients and fluctuations change on finite time scales, so the current response need not be instantaneous. Using a Maxwell--Cattaneo-type extension of diffusion as a minimal framework, we study equal-time correlation functions and their mapping to finite-acceptance cumulants. The current relaxation time introduces a new dynamical scale that modifies the relaxation pattern of fluctuations and affects their imprint on experimentally relevant cumulants.