Gruppo di Fisica Statistica

We study the off-equilibrium relaxational dynamics at criticality in the three-dimensional Blume-Capel model whose static critical behaviour belongs to the 3d-Ising universality class. Using "improved" Hamiltonian (the leading corrections to scaling have vanishing amplitude) we perform Monte Carlo simulations of the relaxational dynamics after a quench from ${\footnotesize T=\infty}$ to ${\footnotesize T_c}$. Analysing the off-equilibrium dynamics at ${\footnotesize T_c}$ we obtain an estimate of the dynamical critical exponent ${\footnotesize z=2.020(8)}$ that is perfectly consistent with the Field Theory predictions.