Reduction of shot-noise in quantum conductors

In a quantum conductor, electrons propagate coherently, i.e. the electronic waves keep a well defined phase. Thus one can observe a wealth of new interesting effects, directly related to the quantum nature of the system. Transport measurements provide information on the wave nature of the electrons, via the transmission of the associated waves, in the frame of the so-called scattering theory. Alternatively, Shot-Noise gives information on the corpuscular behaviour of the electrons, by reflecting the random transfer of charge quanta. Moreover, in a quantum conductor, the noise is sensitive to the particle statistics : the Pauli exclusion principle correlates the flow of electrons, thus reducing the Shot-Noise below the classical value 2eI observed in usual classical electronic devices. More generally, it is expected that quantum conductors are less noisy than their classical analog. In this paper, we present an experiment on the simplest quantum conductor, a Quantum Point Contact ; the fine control of the transmission of electronic waves, allows observation of wave-like as well as particle-like effects.