Séminaire du LPTMS: Charles Grenier


11:00 - 12:00

LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay
15 Rue Georges Clemenceau, Orsay, 91405
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Characterization and decoherence of minimal excitations

Charles Grenier, CPhT Ecole Polytechnique

The recent years saw the developments of quantum optics experiments with electrons propagating along the edge channels of two-dimensional electron gases in the quantum Hall regime [1]. In this context, the realization of single electron sources is necessary to observe analogues of the fundamental results of quantum optics, such as the Hong-Ou-Mandel effect. In the electronic context, these experiments would provide unprecendented insights on the behavior of electron gases at the single-particle level [2]. In this talk, I will present a theoretical study of the single electron coherence properties of two different types of voltage pulses [3,4]. By combining bosonization and the Floquet scattering approach, the effect of interactions on a periodic source of voltage pulses is computed exactly [5]. When such excitations are injected into one of the channels of a system of two copropagating quantum Hall edge channels, they fractionalize into pulses whose characteristics reflects the properties of interactions. We show that the dependence of fractionalization induced electron/hole pair production in the pulses amplitude contains clear signatures of the fractionalization of the individual excitations. We propose an experimental setup combining a source of Lorentzian pulses [3] and an Hanbury Brown and Twiss interferometer to measure interaction induced electron/hole pair production and more generally to reconstruct single electron coherence of these excitations before and after their fractionalization.
[1] Y. Ji, et al, Nature 422, 415 (2003)
[2] P. Degiovanni, et al, Phys. Rev. B 80, 241307(R) (2009)
[3] L. Levitov, et al, J. Math. Phys. 37, 4845 (1996); D. A. Ivanov, et al, Phys. Rev. B 56, 6839 (1997); J. Keeling, et al, Phys. Rev. Lett. 97, 116403 (2006)
[4] J. Dubois, et al, preprint ArXiv:1212.3921
[5] Ch. Grenier, et al, ArXiv:1301.6777

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