Training Schr�dinger�s cat: quantum optimal control.

Abstract 

It is control that turns scientific knowledge into useful technology: in physics and 
engineering it provides a systematic way for driving a dynamical system from a given 
initial state into a desired target state with minimized expenditure of energy and 
resources. As one of the cornerstones for enabling quantum technologies, optimal 
quantum control keeps evolving and expanding into areas as diverse as quantumenhanced 
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. In this communication, state-of-the-art
quantum control techniques are reviewed and put into perspective by a consortium of 
experts in optimal control theory and applications to spectroscopy, imaging, as well 
as quantum dynamics of closed and open systems. We address key challenges and sketch a
roadmap for future developments.