Noise exponent in superconducting-normal metal mixtures

The noise exponent κ^' is calculated in a superconductor-normal-conductor network near the percolation threshold using the Midgal-Kadanoff bond-moving method. In two dimensions, κ^'=1.339=κ, where κ is the noise exponent in a normal conductor-insulator network, consistent with duality arguments. In three dimensions, κ^'=0.660, which lies between the exact upper and lower bounds 0.38≤κ^'≤1.02.