Series Study of a Spin-Glass Model in Continuous Dimensionality

A high-temperature series expansion for the Edwards and Anderson spin-glass order-parameter susceptibility is computed for Ising spins on hypercubic lattices with nearest-neighbor interactions. The series is analyzed by Padé approximants with Rudnick-Nelson-type corrections to scaling. The results agree with the first-order ε expansion of Harris, Lubensky, and Chen. The critical exponent γQ increases monotonically with decreasing dimension, d, for d\u3c6, and apparently tends to infinity at d=4; however, the critical temperature does not appear to go to zero at d=4