Drag force near the QCD critical point

We discuss how heavy quark dynamics is affected by the critical fluctuations near the QCD critical point at finite temperature and density. We find that the heavy quark momentum diffusion constant scales as $\kappa \propto {\xi }^{z-3-\eta }$. In the model H scenario, which is widely accepted for the critical dynamics, the exponents are known as $z\simeq 3,\eta \sim 0.04$ and the critical singularity of $\kappa$ is not significant if any. In the model B scenario, $z\simeq 4$ and $\kappa \propto \xi$ is singular near the critical point.