We study numerically the resistance fluctuations, δR, in a disordered metallic microstructure with several probes within a single quantum coherent region. The strong influence of the probes causes δR to depend on the geometry of the coherent region. In a particular four-probe structure, δR is only weakly dependent on the voltage probe separation, in agreement with experiment, while the strong dependence of δR on separation in other structures should be experimentally observable. Nonlocal fluctuations decay slowly as the distance between the current path and voltage probes increases.

• Received 7 January 1988

DOI:https://doi.org/10.1103/PhysRevB.37.6521