Phase transition in the three-dimensional +/-J Ising spin glass

We have studied the three-dimensional Ising spin glass with a +/-J distribution by Monte Carlo simulations. Using larger sizes and much better statistics than in earlier work, a finite-size scaling analysis shows quite strong evidence for a finite transition temperature T-c with ordering below T-c. Our estimate of the transition temperature is rather lower than in earlier work, and the value of the correlation length exponent v is somewhat higher. Because there may be (unknown) corrections to finite-size scaling, we do not completely rule out the possibility that T-c=0 or that T-c is finite but with no order below T-c. However, from our data, these possibilities seem less likely.