I study quantum optics and its applications in quantum information processing. Quantum physics is a peculiar and counterintuitive field of physics that describes the behaviour of individual atoms or larger systems cooled to extremely low temperatures; the subfield of quantum optics focuses on the interaction of these systems with light. Like many other researchers the world over, I am trying to understand how we can use the unusual features of these systems to build better, more efficient computers, communicate more securely, or measure properties of various objects with better precision.

I am a theoretical physicist. I don’t spend my days in a laboratory building experiments and collecting data. Instead, I try to come up with ideas for new experiments others can do or, occasionally, understand what they measured. My work therefore involves a lot of mathematical calculations as I try to understand how a certain system can be described and how it behaves. To make sure that my ideas are feasible, I often run numerical simulations on my computer to see how well an experiment with realistic parameters would work.

As our knowledge progresses, the experiments scientists can perform and their description become more and more complex. We know that while a quantum system might be a good choice for, say, quantum computing, it wouldn’t be suitable for sending quantum information between two places. Experiments are thus starting to focus on combining several quantum systems into larger systems. Such hybrid quantum systems can use the advantages of their building blocks and form devices capable of more than their subsystems alone.

Hybrid quantum systems pose many challenges to a theoretical physicist. A deep understanding of various quantum systems is necessary to find ways to build new hybrid quantum devices that are both feasible and useful. On the other hand, one needs to develop new mathematical tools that capture the main features of the resulting hybrid systems; the complexity does not allow one to describe and understand hybrid quantum systems in full detail.