SLOW DYNAMICS IN 3D+/- J-HEISENBERG SPIN-GLASS - MONTE-CARLO ANALYSIS OF AUTOCORRELATION FUNCTIONS OF INDIVIDUAL SPINS

Slow dynamics in the 3D +/- J Heisenberg spin glass is investigated by the Monte Carlo simulation, in which auto-correlation functions q(i)(t) of all individual spins in the system are evaluated. The distribution of 'relaxation times, tau(i), is extracted from q(i)(t). The forms of the log(tau(i)) distribution obtained reveal that slow dynamics in this system at relatively low temperatures (T less than or similar 0.6J) is nothing but the critical slowing down associated with the T = 0 phase transition. The two decay forms of the total auto-correlation function q(t) (=N-1 SIGMA(i) q(i)(t), N being the number of spins in the system) proposed previously, i.e. the logarithmic decay and the exponential one multiplied by an argebraic factor, are understood as characteristic features of the phenomenon in different ranges of the observation time.