Ultra-stable optical oscillators from quantum coherent and entangled systems

From advanced navigation and telecommunications to radio astronomy and the testing of fundamental physical laws, the most precise and accurate time measurements are required. To meet these technical challenges, optical clock development is at the forefront of research in this field. The state-of-the-art technology, however, has its limits: frequency stability of the lasers used in such systems is affected both by thermal noise from mirror coatings and more fundamentally by so-called quantum projection noise (QPN). Advanced quantum-based sensors could also be realised if current technical constraints could be surpassed.

This project will implement, study and characterise both established and brand-new methods for the development of optical clocks. To go beyond noise limits and increase frequency stability, multi-particle entanglement of atoms/ions will be investigated; this phenomenon could also be exploited for electromagnetic field measurements with enhanced sensitivity. The project results will support future realisations of the SI second through new frequency standards and significantly impact many fields requiring ultra-precise time measurement.