An ultrafast, vectorized spin-dynamics method is used to study the time-dependent properties of classical XY and Heisenberg spin chains at infinite temperature. The decay of the energy-energy and spin-spin correlation functions is oscillatory for short times and at long times is consistent with classical diffusion, although the approach to the asymptotic behavior is extremely slow. We have also calculated S(q,ω) and find clear indication of spin-wave peaks in both models.

• Received 16 March 1990

DOI:https://doi.org/10.1103/PhysRevB.42.8214