"Magic" radio-frequency dressing for trapped atomic microwave clocks

TL;DR

This paper introduces a radio-frequency dressing technique to cancel higher-order magnetic field effects in trapped atomic microwave clocks, significantly reducing dephasing and improving clock stability.

Contribution

It presents a novel method using weak radio-frequency dressing to cancel both first and second order magnetic field dependencies in atomic clocks.

Findings

Radio-frequency dressing can suppress dephasing by over tenfold.

The method is robust against parameter variations.

Quantitative values for optimal dressing conditions are provided.

Abstract

It has been proposed to use magnetically trapped atomic ensembles to enhance the interrogation time in microwave clocks. To mitigate the perturbing effects of the magnetic trap, near-magic-field configurations are employed, where the involved clock transition becomes independent of the atom's potential energy to first order. Still, higher order effects are a dominating source for dephasing, limiting the performance of this approach. Here we propose a simple method to cancel the energy dependence to both first and second order, using weak radio-frequency dressing. We give values for dressing frequencies, amplitudes, and trapping fields for 87Rb atoms and investigate quantitatively the robustness of these second-order-magic conditions to variations of the system parameters. We conclude that radio-frequency dressing can suppress field-induced dephasing by at least one order of magnitude for typical experimental parameters