Jeudi 22 mai 2014 à 11h00
Salle 234, Ecole de Physique

Using a two-electron spin-qubit to detect flying electrons above the Fermi sea

Tristan Meunier, Institut Néel, Grenoble

In quantum optic experiments with flying electrons, the flying electrons are so far detected via current measurement, summing up the contribution of millions of electron transfers between two contact pads and electron correlations are encrypted in the current noise. This represents an important limitation for the investigation of quantum correlations in experiments with flying electrons. To overcome this limitation, it is necessary to detect an individual flying electron passing by a detector, a very difficult task to tackle with conventional detectors. Nevertheless, quantum systems have been identified as extremely sensitive systems to external perturbations and potentially good detectors. Here, we propose and demonstrate experimentally the potential of a two-electron spin qubit as an ultrasensitive charge detector by capacitively coupling it to individual electrons, propagating in the edge states of the Quantum Hall regime. We demonstrate that the qubit is an ultrasensitive and fast charge detector with the potential to allow single shot detection of a single flying electron. This work opens the route towards quantum electron optics at the single electron level above the Fermi sea.