Auto- versus Cross-Correlation Noise in Periodically Driven Quantum Coherent Conductors

Expressing currents and their fluctuations at the terminals of a multi-probe conductor in terms wave functions carriers injected into Fermi sea provides new insight physics electric currents. This approach helps us to identify two physically different contributions shot noise. In quantum coherent regime, when current is carried by non-overlapping packets, product leads, cross-correlation noise, determined solely duration packet. contrast, square one lead, autocorrelation additionally coherence packet, which associated with spread packet energy. The can be addressed separately weak back-scattering noise depends only on coherence. Analysis these allows us, particular, predict that no individual traveling particles real function, such as Majorana fermions, created clean manner, is, without accompanying electron–hole pairs.