Dynamical behavior of the random-bond transverse Ising model with four-spin interactions

We study the time evolution of the one-dimensional random-bond transverse I sing model with four-spin interactions. We calculate the time-dependent cor relation function as well as the longitudinal relaxation function of the in finite chain. We analyze how the presence of disorder affect the dynamical behavior of the system in comparison with the pure model. We find that the main effect of disorder is to produce a crossover from a central mode to a collective-mode type of dynamics, as the concentration of weaker bonds is e nhanced. Such crossover is also present in the case of an increase in bond dilution.