title: Coherent adiabatic spin control in the presence of charge noise using tailored pulses.
abstract: We study finite-time Landau-Zener transitions at a singlet-triplet level crossing in a GaAs double quantum dot, both experimentally and theoretically. Sweeps across the anticrossing in the high driving speed limit result in oscillations with a small visibility. Here we demonstrate how to increase the oscillation visibility while keeping sweep times shorter than T(2)(*) using a tailored pulse with a detuning dependent level velocity. Our results show an improvement of a factor of ~2.9 for the oscillation visibility. In particular, we were able to obtain a visibility of ~0.5 for Stückelberg oscillations, which demonstrates the creation of an equally weighted superposition of the qubit states.
authors.affiliation: Department of Physics, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Hugo
authors.initials: H
authors.lastname: Ribeiro
authors.forename: Guido
authors.initials: G
authors.lastname: Burkard
authors.forename: J R
authors.initials: JR
authors.lastname: Petta
authors.forename: H
authors.initials: H
authors.lastname: Lu
authors.forename: A C
authors.initials: AC
authors.lastname: Gossard