Quantum technologies and quantum control

Quantum mechanics is at the basis of all present-day information and communication technologies: to name just two examples, transistors and lasers would be impossible to build without understanding the quantum behaviour of matter and light. But the control of individual quantum systems has long been considered only a “thought experiment”, something only possible in theory. However, today this is routinely achieved in labs around the world, and it is the basis of quantum technologies. After reviewing the main applications of quantum technologies, ranging from secure communications to ultra-high precision sensing and metrology, and from extremely powerful computers to the simulation of complex materials, I will present the common vision underlying the recently proposed Quantum Manifesto, which will be a basis for the upcoming Flagship initiative on Quantum Technologies.

To achieve this vision in real environments, we need to push our ability to control the dynamics of increasingly complex quantum systems to its limits. In the case of quantum systems with few particles, the decoherence occurring due to the interaction with the environment hinders the realisation of desired processes. In quantum many-body systems, the complexity of their dynamics makes the state preparation by external manipulation more difficult. I will show that Quantum Optimal Control Theory provides an effective strategy to overcome these problems. Quantum coherence is used to achieve a desired target with high accuracy, even under real conditions. I will present current experiments that have been made possible by our new optimal control algorithm, and explain how we can use such methods to push the limits of the physical realisation of quantum technologies.

Bio: Prof. Dr. Tommaso Calarco (Institute for Quantum Complex System, University of Ulm) has pioneered the application of quantum optimal control methods to quantum computation and to many-body quantum systems. He is the director of the centre IQST, which involves the University of Ulm, Stuttgart and the Max Planck Institute for Solid State Research. He is one of the author of the “Quantum Manifesto” and scientific member of the “High Level Steering Committee for the Quantum Technologies Flagship”.