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Time-resolved measurements of collective effects in quantum conductors

Vendredi 7 février 14:30 - Duree : 2 heures
Lieu : CNRS - Amphithéâtre-bâtiment A-3ème étage - 25 rue des Martyrs, Grenoble 38054

Orateur : Soutenance de Thèse de Everton ARRIGHI

Quantum dynamics is very sensitive to dimensionality. While two-dimensional electronic systems form Fermi liquids, one-dimensional systems – Tomonaga–Luttinger liquids – are described by purely bosonic excitations, even though they are initially made of fermions. With the advent of coherent single-electron sources, the quantum dynamics of such a liquid is now accessible at the single-electron level. In this PhD work, we study the most general case where the system can be tuned continuously from a clean one-channel Tomonaga–Luttinger liquid to a multi-channel Fermi liquid in a non-chiral system. We use time-resolved measurement techniques to determine the time of flight of a single-electron voltage pulse and extract the collective charge excitation velocity. Analysing the propagation velocity allows to reveal the collective effects that govern the physics in our quasi one-dimensional system. Our detailed modelling of the electrostatics of the sample allows us to construct and understand the excitations of the system in a parameter-free theory. We show that our self-consistent calculations capture well the results of the measurements, validating the construction of the bosonic collective modes from the fermionic degrees of freedom. The presented time control of single-electron pulses at the picosecond level will also be important for the implementation of waveguide architectures for flying qubits using single electrons. Integrating a leviton source into a waveguide interferometer would allow to realise single-electron flying qubit architectures similar to those employed in linear quantum optics. Furthermore, our studies pave the way for studying real-time dynamics of a quantum nanoelectronic device such as the measurement of the time spreading or the charge fractionalisation dynamics of the electron wave packet during propagation.

Contact : everton.arrighi@neel.cnrs.fr

Discipline évènement : (Physique)
Entité organisatrice : (Institut Néel)
Nature évènement : (Soutenance de thèse)
Site de l'évènement : Polygone scientifique

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