Some Phenomenological Properties of the Chiral Transition in QCD

On the basis of the NJL model as an effective theory of QCD and analogies with condensed matter physics, we extract simple physical pictures of the chiral phase transition at finite temperature $T$ and/or chemical potential $\mu$ and predict interesting phenomena associated with the phase transition which may be seen in relativistic heavy-ion collisions to be performed in RHIC or LHC. We indicate that the macroscopic equation describing non-equilibrium phenomena of the chiral transition like DCC might be given by a diffusion-like equation rather than a wave equation especially when the baryon density is present.