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. Sweeps across the anti-crossing in the low driving speed limit match well with theoretical predictions based on the asymptotic Landau-Zener scattering approach. In particular, we only observe interference fringes when the detuning is swept through the anti-crossing. In contrast, for short rise-time pulses we find oscillations on both sides of the anti-crossing, as expected from finite-time theory. We demonstrate that both of these results are compatible if spin and charge degrees of freedom are taken into account in the time-dependent dynamics. We show that charge noise induces a competing mechanism against Landau-Zener transitions, which can be canceled by choosing appropriately tailored detuning pulses.