Continuous-variable tomography of on-demand ballistic electrons
Mardi 21 janvier 2020 14:00
- Duree : 1 heure
Lieu : Salle « Remy Lemaire » (K223) de l’Institut Néel – au n°25 de la rue des martyrs, Grenoble.
Orateur : Vyacheslavs KASHCHEYEVS (University of Latvia)
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Resumé / Abstract :
Individual electrons in semiconductors circuits that can either be confined to quantum dots or guided ballistically along nanowire edges form an exciting quantum technology platform being actively developed for applications in metrology, quantum sensing and quantum information transfer. Precision of electron counting is rivalling most precise conventional measurements of small currents in ongoing progress towards direct realisation of the quantum ampere in the redefined SI. Availability of on-demand electron sources has enabled chip-level collider and tomography experiments aimed to develop a full toolkit for a few-electron quantum optics.
We discuss a recently proposed and implemented quantum tomography technique for solitary electrons propagating in a chiral edge state in a depleted region of a two-dimensional quantum Hall system. Quasi-probability distribution of complementary continuous variables — arrival time and energy — is accessed by measuring probabilities of scattering from a time-dependent energetically sharp gate-controlled barrier. Wigner distribution is recovered from the spectrum of projections at different modulation speeds using standard techniques of tomographic imaging. We resolve a chirp in the energy of electrons emitted on demand from a tuneable barrier pump, and put a lower bound on the quantum coherence of the source.
Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr
Discipline évènement : (Physique)
Entité organisatrice : (Fondation Nanosciences)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire Nanoélectronique Quantique)
Site de l'évènement : Polygone scientifique
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