Introduction to quantum control: From basic concepts to applications in quantum technologies

TL;DR

This paper provides a comprehensive overview of quantum control techniques, including basic principles and advanced methods like optimal control, with applications to atoms and superconducting qubits, highlighting recent research and future directions.

Contribution

It offers an integrated tutorial on quantum control concepts, combining foundational principles with recent research applications and discussing future challenges.

Findings

Demonstrates effective manipulation of atoms and qubits using quantum control methods.

Highlights the importance of optimization functional choice in optimal control.

Discusses potential integration of coherent control with engineered dissipation.

Abstract

Quantum control refers to our ability to manipulate quantum systems. This tutorial-style chapter focuses on the use of classical electromagnetic fields to steer the system dynamics. In this approach, the quantum nature of the control stems solely from the underlying dynamics, through the exploitation of destructive and constructive interference to reach the control target. We first discuss two basic control principles -- coherent control which uses manipulation in frequency or time to design these interferences, and adiabatic following where access to the control target is enabled by tracking the time-dependent ground state. For complex control targets and system dynamics that exceed the scope of these basic principles, optimal control theory provides a powerful suite of tools to design the necessary protocols. A key consideration for the successful application of optimal control theory is a proper choice of the optimization functional. All concepts are illustrated using recent work from my research group, with a focus on controlling atoms and superconducting qubits. The chapter concludes with an outlook on integrating coherent control with engineered dissipation and a discussion of open questions in the field.