Gwendal Fève, LPA, ENS

Jeudi 11 Fevrier 2015 14h
Amphi Holweck, Esc C, 1ème etage

Titre:Electron quantum optics in quantum Hall edge channels

Quantum effects have been studied on photon propagation in the context of quantum optics since the second half of the last century. In particular, using single photon emitters, fundamental tests of quantum mechanics were explored by manipulating single to few photons in Hanbury-Brown and Twiss and Hong Ou Mandel [1] experiments.
In nanophysics, there is a growing interest to translate these concepts of quantum optics to electrons propagating in nanostructures. In two-dimensional electron gases, electronic propagation can be guided along the edge channels of the quantum Hall effect and quantum point contacts can be used as electronic beam-splitters to implement electronic interferometers [2]. Single electron emitters have also been realized such that single elementary electronic excitations can now be manipulated in the analog of pioneer quantum optics experiments. However, these electron quantum optics experiments go beyond the mere reproduction of optical setups using electron beams, as electrons, being interacting fermions, differ strongly from photons.
I will discuss in particular the electronic analog [3, 4] of the Hong-Ou-Mandel experiment (see Figure) where two single electrons collide on a beam-splitter. Two-particle interferences between two indistinguishable single electrons can then reveal the coherence properties of single electron states and probe how they are affected by the Coulomb interaction along propagation [5,6,7].

References :
[1] C. K. Hong, Z. Y. Ou, and L. Mandel Physical Review Letters 59, 20442046 (1987).
[2] Y. Ji et al. Nature 422, 415–418 (2003).
[3] S. Ol’khovskaya, J. Splettstoesser, M. Moskalets, M. Büttiker, Phys. Rev. Lett. 101, 166802 (2008)
[4] E. Bocquillon et al., Science 339, 1054 (2013).
[5] D. Ferraro et al., Phys. Rev. Lett. 113, 166403 (2014).
[6] C. Wahl, J. Rech, T. Jonckheere, T. Martin, Phys. Rev. Lett. 112, 046802 (2014).
[7] V. Freulon et al., Nat. Commun. 6, 6854 (2015).

Sketch of electronic Hong-Ou-Mandel experiment : the two dimensional electron gas
is pictured in green, the metallic gates in gold and the edge channels by red dashed lines

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