An Atomic-Array Optical Clock with Single-Atom Readout

• Published in: Physical review. X 2019-12, Vol.9 (4), p.041052, Article 041052
• Main Authors: Madjarov, Ivaylo S., Cooper, Alexandre, Shaw, Adam L., Covey, Jacob P., Schkolnik, Vladimir, Yoon, Tai Hyun, Williams, Jason R., Endres, Manuel
• Format: Article
• Language: English
• Subjects: Arrays; Atomic properties; Clock systems; Clocks; Clocks & watches; Control stability; Feedback control; Geodesy; Interrogation; Metrology; Monte Carlo simulation; Neutral atoms; Optical lattices; Performance degradation; Quantum computing; Quantum entanglement; Simulation; Stability analysis; Systematic errors
• ISSN: 2160-3308; 2160-3308
• DOI: 10.1103/PhysRevX.9.041052

Currently, the most accurate and stable clocks use optical interrogation of either a single ion or an ensemble of neutral atoms confined in an optical lattice. Here, we demonstrate a new optical clock system based on an array of individually trapped neutral atoms with single-atom readout, merging many of the benefits of ion and lattice clocks as well as creating a bridge to recently developed techniques in quantum simulation and computing with neutral atoms. We evaluate single-site-resolved frequency shifts and short-term stability via self-comparison. Atom-by-atom feedback control enables direct experimental estimation of laser noise contributions. Results agree well with an ab initio Monte Carlo simulation that incorporates finite temperature, projective readout, laser noise, and feedback dynamics. Our approach, based on a tweezer array, also suppresses interaction shifts while retaining a short dead time, all in a comparatively simple experimental setup suited for transportable operation. These results establish the foundations for a third optical clock platform and provide a novel starting point for entanglement-enhanced metrology, quantum clock networks, and applications in quantum computing and communication with individual neutral atoms that require optical-clock-state control.