Mesoscopic versus Macroscopic division of current fluctuations

We investigate the current shot noise at a three terminal node in which one of the branches contains a noise generating source and the correlations are measured between the currents flowing through the other two branches. Interestingly, if the node is macroscopic, the current correlations are positive, whereas for a quantum coherent mesoscopic node anti-bunching of electrons leads to negative correlations. We present specific predictions which permit the experimental investigation of the crossover from quantum mechanical noise division to macroscopic noise noise division.