Positive and negative Hanbury-Brown and Twiss correlations in normal metal-superconducting devices
Centre de Physique Théorique,
Université de la Méditerranée,
Case 907, 13288 Marseille Cedex 9,
Published online: 15 December 1999
In the light of the recent analogs of the Hanbury-Brown and Twiss experiments [CITE] in mesoscopic beam splitters, negative current noise correlations are recalled to be the consequence of an exclusion principle. Here, positive (bosonic) correlations are shown to exist in a fermionic system, composed of a superconductor connected to two normal reservoirs. In the Andreev regime, the correlations can either be positive or negative depending on the reflection coefficient of the beam splitter. For biases beyond the gap, the transmission of quasiparticles favors fermionic correlations. The presence of disorder enhances positive noise correlations. Potential experimental applications are discussed.
PACS: 74.40.+k – Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.) / 74.50.+r – Proximity effects, weak links, tunneling phenomena, and Josephson effects / 72.70.+m – Noise processes and phenomena
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999