QDev Seminar: Jeremie Viennot – University of Copenhagen

QDev Seminar: Jeremie Viennot

Charge and spin dynamics in a hybrid cQED architecture.

In the context of circuit quantum electrodynamics, recent developments made it possible to build hybrid circuits [1], including many types of quantum dots. The versatility of these systems allows us to explore several directions, from quantum information engineering to many-body physics, all in a circuit QED architecture. I will present some of the experiments of our group where a carbon nanotube-based double quantum dot is coupled to a microwave cavity. Using a novel carbon nanotube stamping technique [2], we demonstrate a strong electron confinement, allowing us to bring the system at resonance with the cavity and use it as a charge qubit. We characterise the response of this circuit out of equilibrium, driving the system either with a finite bias or with a microwave spectroscopic tone [3].

Combined with exchange Zeeman fields induced by ferromagnetic interfaces, such a control should enable us to go towards spin-photon coupling and spin qubit experiments for circuit QED [4]. I will discuss some preliminary results pointing towards spin-photon coupling signatures in such an architecture.

References :
[1] M.R. Delbecq et al. Nature Comm., 4, 1400 (2013).
[2] J.J. Viennot et al., APL 104, 113108 (2014).
[3] J.J. Viennot et al., PRB 89, 165404 (2014).
[4] A. Cottet et al., Phys. Rev. Lett. 105, 160502 (2010).