Jörg Müller's Quantum Metrology group works on next-generation optical atomic clocks and superradiant lasers. Key experiments: cold strontium continuous superradiant laser (subnatural linewidth, pushing beyond traditional clock limitations); microresonator-based frequency combs; ultra-stable optical reference cavities; and cavity QED many-atom systems for clocks and sensing. The group is part of the EU iqClock project targeting operational optical lattice clocks.

Stefan Schäffer leads the Quantum Metrology group at NBI together with Jörg Müller. Research focuses on superradiant strontium lasers: (1) quasi-continuous superradiant lasing with sub-natural linewidth; (2) Ramsey spectroscopy enhanced by cavity sub-to-superradiant phase transitions for improved atomic clock sensing; (3) continuous atom beam for Dicke-effect-free superradiant interrogation. Key work published in PRL (2023) and Nature Communications (2024). Part of EU iqClock and ESA collaborations.