How does delayed current response shape particle fluctuations in extreme matter?

During the quark-gluon plasma's brief existence after a heavy-ion collision, fluctuations in conserved charges encode clues about the QCD critical point. The standard model assumes diffusive currents respond instantaneously to density gradients, but the team shows that when current relaxation takes finite time—like overdamped springs with history—it introduces additional memory effects. These suppress and reshape the non-monotonic patterns in higher-order cumulants that experiments measure, potentially changing how we interpret critical-point signatures.