Controlled confinement to reduce the inaccuracy of clocks based on optical lattices

In quantum sensing, optical lattice clocks (OLCs) are emerging as one of the most precise measurement instruments, finding application in areas from geodesy to the search for dark matter and the definition of time and frequency. For the redefinition of the SI second, the fundamental limits and robustness of OLCs need to be established in order to understand their ultimate capabilities. There is a lack of information about the effects of trap topology, cavity coupling and optomechanical effects on OLC accuracy and the metrological capabilities of novel platforms such as optical tweezers and hollow core fibres require further investigation.

This project will study systematic effects associated with light-shifts caused by the lattice and cold collisions between atoms in OLCs, determining how to mitigate collision effects and de-coherence in different OLC configurations. Novel techniques, like optical tweezers, will be used to demonstrate engineered or moveable potentials in dead-time free and active clocks, which will then be used to modify OLC trap geometry to explore cold collisions and other effects. Fast and low-noise readout from hybrid cavity OLCs with strong light-matter interaction will be demonstrated and studied at low fractional resolutions (10^-18 and lower), and the effects of background gas collisions in dipole traps will also be determined. Finally, optical fibre link comparisons between European metrology institutes will be undertaken to demonstrate the improved OCL accuracy gained through the project.

This work will improve the accuracy and robustness of OCLs, leading to improved accuracy in the definition of the SI second. This will have follow-on effects in all areas that rely on frequency and time measurements, from fundamental physics to telecommunications.