Synthetic Frequency Protocol in the Ramsey Spectroscopy of Clock Transitions

TL;DR

The paper introduces a universal synthetic frequency protocol for Ramsey spectroscopy that significantly reduces probe-induced shifts in atomic clocks, enhancing accuracy across various clock types especially when combined with hyper-Ramsey techniques.

Contribution

It adapts the synthetic frequency concept to Ramsey spectroscopy, enabling broad applicability and improved suppression of frequency shifts in optical atomic clocks.

Findings

Probe-induced shifts can be suppressed below 10^{-18} fractional level.

Method is highly efficient and resistant to decoherence effects.

Applicable to various Ramsey schemes and atomic clock types.

Abstract

We develop an universal method to significantly suppress probe-induced shifts in any types of atomic clocks using the Ramsey spectroscopy. Our approach is based on adaptation of the synthetic frequency concept [V. I. Yudin, et al., Phys. Rev. Lett. 107, 030801 (2011)] (previously developed for BBR shift suppression) to the Ramsey spectroscopy with the use of interrogations for different dark time intervals. Universality of the method consists in arbitrariness of the possible Ramsey schemes. However, most extremal results are obtained in combination with so-called hyper-Ramsey spectroscopy [V. I. Yudin, et al., Phys. Rev. A 82, 011804(R) (2010)]. In the latter case, the probe-induced frequency shifts can be suppressed considerably below a fractional level of 10$^{-18}$ practically for any optical atomic clocks, where this shift previously was metrologically significant. The main advantage of our method in comparison with other radical hyper-Ramsey approaches [R. Hobson, et al., Phys. Rev. A 93, 010501(R) (2016); T. Zanon-Willette, et al., Phys. Rev. A 93, 042506 (2016)] consist in much greater efficiency and resistibility in the presence of decoherentization.