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 antibunching of electrons leads to negative correlations. We present specific predictions which permit the experimental investigation of the crossover from the quantum mechanical noise division to the macroscopic noise division.