MOLECULAR-DYNAMICS STUDY OF CLASSICAL ISING-MODEL IN A TRANSVERSE FIELD

The molecular-dynamics technique is applied to the study of the classical (S=a) Ising model in a transverse field on a simple-cubic lattice. The results for the longitudinal- and transverse-relaxation shape function are presented for a set of temperatures in the disordered phase at one value of the transverse field. The longitudinal spectra at T=a and in the critical regime are analyzed via the Mori's continued-fraction expansion and compared with various approximate results within this approach. The relation of the observed central mode to a domain-wall motion is also discussed. However, due to heavy-damping phenomena no well-defined propagating modes are observed in the critical region. Finally, transverse correlation functions are tested against their diffusive character. © 1978 The American Physical Society.