Quantum optics of nano-conductors

Quantum electrodynamics describes the interaction of light and matter. It has been explored with unprecedented accuracy for atoms in optical cavities but lately also in solid state devices with artificial atoms.  A similar level of accuracy has been achieved in controlling charge transfer through  nano-conductors down to single charge quanta. Recently, activities started to combine these previously basically distinct fields, thus  exploring the quantum optics of mesoscopic conductors.

Our group has provided in collaboration with world-leading experimental teams pioneering contributions for the situation, where Cooper pair tunneling through Josephson junctions drives microwave cavities. The strong coupling between charge and light leads to strong feedback effects that can be used to design new sources for non-classical light, e.g., for single photons or entangled photon pairs.  Josephson photonics has turned out to be a fascinating playground for theoretical and technological developments.