Counteracting systems of diabaticities using DRAG controls: The status after 10 years

TL;DR

This paper reviews the DRAG control framework for quantum systems, highlighting its ability to suppress unwanted excitations and reduce operation times through multi-transition counterdiabatic driving, with practical examples.

Contribution

It provides a comprehensive review of DRAG techniques, including recent advances and applications, emphasizing multi-transition control and the use of average Hamiltonian methods.

Findings

DRAG effectively suppresses spectral leakage in quantum control.

Multi-transition DRAG reduces operation times compared to adiabatic methods.

Application examples demonstrate improved quantum gate performance.

Abstract

The task of controlling a quantum system under time and bandwidth limitations is made difficult by unwanted excitations of spectrally neighboring energy levels. In this article we review the Derivative Removal by Adiabatic Gate (DRAG) framework. DRAG is a multi-transition variant of counterdiabatic driving, where multiple low-lying gapped states in an adiabatic evolution can be avoided simultaneously, greatly reducing operation times compared to the adiabatic limit. In its essence, the method corresponds to a convergent version of the superadiabatic expansion where multiple counterdiabaticity conditions can be met simultaneously. When transitions are strongly crowded, the system of equations can instead be favorably solved by an average Hamiltonian (Magnus) expansion, suggesting the use of additional sideband control. We give some examples of common systems where DRAG and variants thereof can be applied to improve performance.