Heuristic approach to the critical dynamics of the Ising model

We discuss order-disorder phase transitions of classical and quantum Ising models on the basis of the Ginzburg-Landau-Wilson free-energy action and a modification of a scaling method proposed by Thompson. The two-time critical relaxation scenario, driven by thermal and quantum fluctuations, respectively, is given in terms of the slow-down critical exponent of the order-parameter excitations.