TRANSITION POINT OF THE RANDOM ISING-MODEL WITH BOND DILUTION

The transition point of the random Ising model on the square lattice is exactly calculated under the assumption of quenched randomness of bond defects. The author makes use of a duality transformation and the replica method. The transition point thus obtained is given by exp(-2Kc)=exp((1-1/2p)ln2) -1 which satisfies the boundary conditions: Tc to 0 as p to p c=1/2; and Kc to 1/ 2ln( square root 2+1) as p to 1.