The on-demand generation of pure quantum excitations is a key issue to operate quantum systems. We have implemented the simplest possible on-demand generation of electrons in a conductor by applying voltage pulses on a contact. For Lorentzian time dependent potential a minimal excitation with only one particle and no hole is generated: a Leviton. Other pulse shapes create more excitations. Their number is measured by the noise generated when partitioning the excitations with an electronic beam-splitter. Minimal states are found for Lorentzian pulses while sine and square pulses show significant holes contribution. Hong-Ou-Mandel noise correlation of Levitons emitted from independent contacts and shot noise spectroscopy characterize the states in time and energy. These minimal excitation states open quantum applications for both atomic and electronic Fermion systems.
See also the News and Views by C. Flindt in Nature

  • Minimal-excitation states for electron quantum optics using levitons, J. Dubois, T. Jullien, F. Portier, P. Roche, A. Cavanna, Y. Jin, W. Wegscheider, P. Roulleau and D. C. Glattli, ** published in Nature 502, 659–663 (2013) dx.doi.org/10.1038/nature12713**see Here
  • Integer and fractional charge Lorentzian voltage pulses analyzed in the framework of photon-assisted shot noise,J. Dubois, T. Jullien, C. Grenier, P. Degiovanni, P. Roulleau, and D. C. Glattli, Ch. Grenier, Phys. Rev. B 88, 085301 (2013), (arxiv)
  • Fractionalization of minimal excitations in integer quantum Hall edge channels, J. Dubois, T. Jullien, P. Roulleau, D. C. Glattli, and P. Degiovanni, Phys. Rev. B 88, 085302 (2013), (arxiv)

Recently the Quantum Tomography of a leviton state has been performed, see:

  • Quantum tomography of an electron, T. Jullien, P. Roulleau, B. Roche, A. Cavanna, Y. Jin, and D. C. Glattli, Nature 514, 603–607 (2014) dx.doi.org/10.1038/nature13821
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Experiment principle: voltage pulses V(t) on the contact of a two-dimensional electron gas generate charge pulses which are partitioned by a quantum point contact (QPC). The split-gate voltage VG controls the transmission D of the one-dimensional electronic mode formed at the QPC.

Advanced Grant