Training Schr\"odinger's cat: quantum optimal control

TL;DR

This paper reviews advanced quantum control techniques, highlighting their importance in developing quantum technologies and discussing future challenges and directions in the field.

Contribution

It provides a comprehensive overview of state-of-the-art quantum control methods and unites expertise from control theory and quantum applications.

Findings

Review of current quantum control techniques

Identification of key challenges in quantum control

Roadmap for future developments in quantum control

Abstract

It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving a system from a given initial state into a desired target state with minimized expenditure of energy and resources -- as famously applied in the Apollo programme. As one of the cornerstones for enabling quantum technologies, optimal quantum control keeps evolving and expanding into areas as diverse as quantum-enhanced sensing, manipulation of single spins, photons, or atoms, optical spectroscopy, photochemistry, magnetic resonance (spectroscopy as well as medical imaging), quantum information processing and quantum simulation. --- Here state-of-the-art quantum control techniques are reviewed and put into perspective by a consortium uniting expertise in optimal control theory and applications to spectroscopy, imaging, quantum dynamics of closed and open systems. We address key challenges and sketch a roadmap to future developments.