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Time-dependent modeling of carriers in quasi 2D systems: indirect excitons and Hall edge states

Mercoledý 12 aprile 2017 – 15.00, aula Seminari, S3 Cnr Nano, Dipartimento FIM, Modena

Relatore: Andrea Bertoni (CNR - NANO S3, Modena, Italia )
Abstract: Hot-electron quantum optics exploits interference phenomena between long-lived electronic excitations driven by appropriate gate pattering in semiconductor nanostructures, and constitutes a major alternative to quantum optics for integrated quantum computing architectures. The time evolution of electronic excitations in models of realistic devices can be obtained by means of a straightforward solution of the quantum equations of motion. In practice, this requires a massively parallel approach and efficient algorithms, particularly when inter-particle interactions are involved.
By using the Fourier split-step simulation technique which allows general, possibly time-dependent, driving external potential to be included in the simulations, we have addressed two systems of current technological interest:

  • Hot electrons in the integer quantum Hall edge states of a 2DEG in a Mach–Zehnder setup. Their evolution exposes the energy-dependent scattering property of a quantum point contacts and its effect on the interferometer visibility.[1]
  • Indirect excitons (optically generated long-lived correlated electron-hole pairs in coupled quantum well devices) accelerated and scattered by static or time-dependent potential patterns. The dominant role of internal correlation in unitary evolution is assessed, making commonly used mean-field methods -which neglect dynamical correlations by construction- to be quantitatively or even qualitatively inadequate to predict transmission coefficients and diffraction patterns in experimental regimes. The shortcoming of mean-field methods are traced to the neglected internal virtual transitions during the scattering process.[2]

[1] A. Beggi, P. Bordone, F. Buscemi, A. Bertoni, J. Phys.: Condens. Matter 27, 475301 (2015); L. Bellentani, A. Beggi, P. Bordone, A. Bertoni, in preparation.
[2] F. Grasselli, A. Bertoni, G. Goldoni, Phys. Rev. B 93, 195310 (2016); Phys. Rev. B 94, 125418 (2016).

Ospiti: Massimo Rontani

[Ultimo aggiornamento: 12/04/2017 11:30:33]