Floquet engineering Hz-Level Rabi Spectra in Shallow Optical Lattice Clock

TL;DR

This paper demonstrates that periodic shaking of a shallow optical lattice clock can produce ultra-narrow Rabi spectra at Hz-level linewidths, enabling improved quantum metrology and quantum simulation.

Contribution

It introduces a novel method of Floquet engineering in shallow optical lattices to achieve narrow Rabi spectra, with independent tuning of Rabi frequency and Bloch bands.

Findings

Achieved 5.4Hz linewidth in Rabi spectra through lattice shaking.

Demonstrated independent control of Rabi frequency and Bloch bands.

Showed potential applications in space-based quantum clocks and quantum simulation.

Abstract

Quantum metrology with ultra-high precision usually requires atoms prepared in an ultra-stable environment with well-defined quantum states. Thus, in optical lattice clock systems deep lattice potentials are used to trap ultra-cold atoms. However, decoherence, induced by Raman scattering and higher order light shifts, can significantly be reduced if atomic clocks are realized in shallow optical lattices. On the other hand, in such lattices, tunneling among different sites can cause additional dephasing and strongly broadening of the Rabi spectrum. Here, in our experiment, we periodically drive a shallow $^{87}$Sr optical lattice clock. Counter intuitively, shaking the system can deform the wide broad spectral line into a sharp peak with 5.4Hz line-width. With careful comparison between the theory and experiment, we demonstrate that the Rabi frequency and the Bloch bands can be tuned, simultaneously and independently. Our work not only provides a different idea for quantum metrology, such as building shallow optical lattice clock in outer space, but also paves the way for quantum simulation of new phases of matter by engineering exotic spin orbit couplings.