Jeudi 02 mars 2006
The quantization of charge leads to fluctuations in the current of a conductor known as shot noise. The first observations by Schottky date back almost a century. In contrast to the classical phenomenon investigated by Schottky, in small phase coherent conductors a shot noise can be observed whose origin is quantum diffraction. We discuss electrical two-particle interferometers which have the property that the conductance exhibits no Aharonov-Bohm effect but shot noise correlations are sensitive to an Aharonov-Bohm flux.
We show that this is a consequence of orbitally entangled two particle states and that the entanglement can be tested by violating a Bell inequality. We complement this discussion with a proposal for a quantum tomography procedure which reveals the maximum information that can be extracted from shot noise measurements.