arXiv subjects

Benoit Rossignol

Publications and source records attributed to Benoit Rossignol.

3 recordsLinked to original sources

arXiv2020

Tkwant: a software package for time-dependent quantum transport

Tkwant is a Python package for the simulation of quantum nanoelectronics devices to which external time-dependent perturbations are applied. Tkwant is an extension of the Kwant package (https://kwant-project.org/) and can handle the same types of systems: discrete tight-binding-like models that consist of an arbitrary central region connected to semi-infinite electrodes. The problem is genuinely many-body even in the absence of interactions and is treated within the non-equilibrium Keldysh formalism. Examples of Tkwant applications include the propagation of plasmons generated by voltage pulses, propagation of excitations in the quantum Hall regime, spectroscopy of Majorana fermions in semiconducting nanowires, current-induced skyrmion motion in spintronic devices, multiple Andreev reflection, Floquet topological insulators, thermoelectric effects, and more. The code has been designed to be easy to use and modular. Tkwant is free software distributed under a BSD license and can be found at https://tkwant.kwant-project.org/.

cond-mat.mes-hall↗

arXiv2019

Role of the quasi-particles in an electric circuit with Josephson junctions

While Josephson junctions can be viewed as highly non-linear impedances for superconducting quantum technologies, they also possess internal dynamics that may strongly affect their behavior. Here, we construct a computational framework that includes a microscopic description of the junction (full fledged treatment of both the superconducting condensate and the quasi-particles) in presence of a surrounding electrical circuit. Our approach generalizes the standard ResistorCapacitor-Josephson model (RCJ) to arbitrary junctions (including e.g. multi-terminal geometries and/or junctions that embed topological or magnetic elements) and arbitrary electric circuits treated at the classical level. By treating the superconducting condensate and quasi-particles on equal footings, we capture non-equilibrium phenomena such as Multiple Andreev Reflection. We show that the interplay between the quasi-particle dynamics and the electrical environment leads to the emergence of new phenomena. In a RC circuit connected to single channel Josephson junction, we find out-of-equilibrium current-phase relations that are strongly distorted with respect to the (almost sinusoidal) equilibrium one, revealing the presence of high harmonic AC Josephson effect. In an RLC circuit connected to a junction, we find that the shape of the resonance is strongly modified by the quasi-particle dynamics: close to resonance, the current can be smaller than without the resonator. Our approach provides a route for the quantitative modeling of superconducting based circuits.

cond-mat.supr-con↗

arXiv2018

Toward flying qubit spectroscopy

While the coherent control of two level quantum systems ---qubits--- is now standard, their continuum electronic equivalents ---flying qubits--- are much less developed. A first step in this direction has been achieved in DC interferometry experiments. Here, we propose a simple setup to perform the second step, the spectroscopy of these flying qubits, by measuring the DC response to a high frequency AC voltage drive. Using two different concurring approaches --- Floquet theory and time-dependent simulations --- and three different models --- an analytical model, a simple microscopic model and a realistic microscopic model --- we predict the power-frequency map of the multi-terminal device. We argue that this spectroscopy provides a direct measurement of the flying qubit characteristic frequencies and a key validation for more advanced quantum manipulations.

cond-mat.mes-hall↗