Coherent Adiabatic Spin Control in the Presence of Charge Noise Using Tailored Pulses

TL;DR

This paper demonstrates a method to enhance the visibility of Landau-Zener-Stückelberg oscillations in a quantum dot system by using tailored detuning pulses, enabling better qubit superposition control within coherence times.

Contribution

It introduces a tailored pulse technique that increases oscillation visibility in Landau-Zener transitions, improving qubit control in quantum dots.

Findings

Visibility improved by a factor of ~2.9

Achieved ~0.5 visibility in St"uckelberg oscillations

Enhanced superposition creation within T2* times

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 T2* using a tailored pulse with a detuning dependent level velocity. Our results show an improvement of a factor ~2.9 for the oscillation visibility. In particular, we were able to obtain a visibility of ~0.5 for St\"uckelberg oscillations, which demonstrates the creation of an equally weighted superposition of the qubit states.