SHOT-NOISE CURRENT-CURRENT CORRELATIONS IN MULTITERMINAL DIFFUSIVE CONDUCTORS

We investigate the correlations in the current fluctuations at differe nt terminals of metallic diffusive conductors. We start from scatterin g matrix expressions for the shot noise and use the Fisher-Lee relatio n in combination with diagram technique to evaluate the noise correlat ions. Of particular interest are exchange (interference) effects analo gous to the Hanbury Brown-Twiss effect in optics. We find that the exc hange effect exists in the ensemble-averaged current correlations. Dep ending on the geometry, it might have the same magnitude as the mean-s quare current fluctuations of the shot noise. The approach that we use is also applied to present a different derivation of the 1/3 suppress ion of shot noise in a two-terminal geometry, which is valid for an ar bitrary relation between the length and wire width. We find that in al l geometries correlations are insensitive to dephasing.