MONTE-CARLO STUDY OF THE 3-DIMENSIONAL +/- J-ISING SPIN-GLASS MODEL IN A MAGNETIC-FIELD

Several numerical results are presented for the low-temperature phase of the +/- J Ising spin glass in three dimensions. The response of the central spin to random fields applied on the boundary is investigated. It is found that a weak homogeneous field suppresses this response. This fact indicates that the ordered phase becomes unstable in the presence of a uniform field H. Overlaps are also calculated for pairs of systems which have the same bond configuration and different boundary fields. The typical magnitude of the overlaps tends to zero in the thermodynamic limit which indicates that the order parameter q(EA) is vanishing even in the case where H = 0 and T < T(c). Several pictures proposed so far are examined in comparison with the present results.