Regensburg 2004 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

SYSN: Quantum Shot Noise in Nanostructures

SYSN 1: Quantum Shot Noise in Nanostructures

SYSN 1.1: Hauptvortrag

Montag, 8. März 2004, 13:30–14:00, H1

Quantum Shot Noise in Nanostructures: From Schottky to Bell — •Markus Büttiker — Département de Physique Theorique, Université de Genève, CH-1211 Genéve 4, Switzerland.

For more than a decade, theoretical and experimental investigations of noise properties have been at the forefront in our quest to understand the transport properties of small electrical conductors. Initial work aimed at characterizing shot noise with the help of Fano factors: the ratio of the shot noise to full Poisson (Schottky) noise. Later the theory was extended to include not only the second moment (shot noise) but all higher order current correlations. We contrast fully quantum mechanical approaches to this problem with semiclassical discussions. Current fluctuations are often understood as simply a stochastic successive transfer of particles. But an analysis of current-current fluctuations shows that it is possible to invent geometries in which there is no Aharonov-Bohm effect in the conductance (second order interference) but there is very well an Aharonov-Bohm effect in noise-correlations (fourth order interference). We demonstrate that this is a consequence of a two particle Aharonov-Bohm effect: in the tunneling limit it can be connected to orbitally entangled electron-hole states. We show that zero-frequency noise-correlation measurements can be used to proof that these states violate a Bell inequality.