Séminaire du LPTMS: Charles Grenier

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

Date/Time : 19/02/2013 - 11:00 - 12:00

Location : LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay

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