Toward a spin-squeezed strontium optical lattice clock with state-of-the-art stability

Current state-of-the-art optical lattice clocks derive their performance by interrogating the clock transition of classical ensembles of thousands of atoms. With improving local oscillator technology, the independent stability of these clocks is approaching quantum projection noise [1], giving rise to considerable interest in employing spin squeezing to demonstrate a quantum advantage in frequency metrology. To date, implementation of spin squeezing in clocks has been demonstrated for either microwave clocks [2], or optical clocks at 10-13 level stability [3]. In this talk we will present progress toward the development of a spin-squeezed strontium optical clock, with the aim of demonstrating the positive impact of spin-squeezing at stability levels of 10-16 or better.

[1] Oelker, E., Hutson, R.B., Kennedy, C.J. et al. Demonstration of 4.8 × 10−17 stability at 1 s for two independent optical clocks. Nat. Photonics 13, 714–719 (2019).

[2] Kevin C. Cox, Graham P. Greve, Joshua M. Weiner, and James K. Thompson. Deterministic Squeezed States with Collective Measurements and Feedback. Phys. Rev. Lett. 116, 093602 (2016).

[3] Pedrozo-Peñafiel, E., Colombo, S., Shu, C. et al. Entanglement on an optical atomic-clock transition. Nature 588, 414–418 (2020).