Feedback effects on the current correlations in Y-shaped conductors

We study current fluctuations in a coherent Y-shaped conductor connected to external leads with finite impedances. We show that, due to voltage fluctuations in the circuit, the moments of the transferred charges cannot be obtained from simple rescaling of the zero-impedance expressions already in the second moments. As a consequence, we find the cross correlation between the output terminals can, surprisingly, change from negative to positive for certain combinations of the sample conductance and external impedances.