Gwendal Fève (LPA, ENS): Single electron experiments in ballistic quantum conductors

Coherent ballistic electronic transport bears strong analogies with the propagation of photons. In particular, by applying a strong magnetic field perpendicular to the plane of a two dimensional electron gas, the electronic propagation can be guided along the one dimensional quantum Hall edge channels as the propagation of photons can be guided in optical fibers. Using electrostatic gates deposited above the surface of the electron gas, tuneable electron beam-splitters can be implemented allowing to reproduce basic electron optics experiments such as, for example, the realization of an electronic Mach-Zehnder interferometer [1].

So far, these electron optics experiments have been performed by connecting an edge channel to a voltage source which continuously emits electrons in a regular flow.  Using triggered single electron emitters, electron/photon analogies can be pushed to quantum optics experiments based on the controlled manipulation of single particles.  Celebrated experiments such as the one electron Hanbury-Brown and Twiss or the two electrons Hong-Ou-Mandel experiments could then be implemented [2]. Their achievement relies on the ability, firstly to produce on-demand single electronic states and secondly to measure the output correlations of single electron beams.

I will present the measurement of the average current [3] produced by an on-demand electron source that periodically emits a single electron on a quantum Hall edge channel. Here, single particle emission is reflected in the quantization of the current generated by the source in units of the electric charge and the drive frequency. Following quantum optics, where light intensity correlations (or so called Hanbury-Brown and Twiss interferometry) are used to demonstrate on demand single photon emission, short time current correlations (or high frequency noise) are also measured to assess the quality of the single electron emitter. When perfect single electron emission is reached, the noise reduces to a fundamental limit associated with the random delay (or jitter) between successive single particle emissions [4,5].

The generation and characterization of these single particle states in solid state provide a new resource to study the many-body interaction between a single electronic excitation and the surrounding Fermi sea.

[1] Y. Ji et al., Nature 422, 415 (2003).
[2] S. Ol'khovskaya et al., Phys. Rev. Lett. 101, 166802 (2008).
[3] G. Fève et al., Science 316, 1169 (2007).
[4] A. Mahé et al., arXiv:1004.1985 (2010).
[5] M. Albert et al., Phys. Rev. B 82, 041407 (2010).