Finite-size effects on critical diffusion and relaxation towards metastable equilibrium

We present an analytic study of finite-size effects on-critical diffusion above and below T-c of three-dimensional Ising-like systems whose order parameter is coupled to-a conserved density; We also calculate the finite-size relaxation time that governs the critical order-parameter relaxation towards a metastable equilibrium state below T-c. Two universal dynamic amplitude ratios at T-c are predicted and quantitative predictions of dynamic finite-size scaling functions are given that can be tested by Monte Carlo simulations.