Magic frequencies for cesium primary frequency standard

TL;DR

This paper proposes a method to cancel frequency shifts in cesium and rubidium atomic clocks by applying an external magnetic field, making the clock transition frequency insensitive to laser and magnetic field variations.

Contribution

It introduces a technique to achieve 'magic' frequencies where the clock transition is unaffected by external field fluctuations, enhancing atomic clock stability.

Findings

External magnetic field can cancel dynamic Stark shifts.

The method is applicable for any laser frequency sufficiently detuned from resonance.

Enhanced stability of atomic frequency standards demonstrated.

Abstract

We consider microwave hyperfine transitions in the ground state of cesium and rubidium atoms which are presently used as the primary and the secondary frequency standards. The atoms are confined in an optical lattice generated by a circularly polarized laser field. We demonstrate that applying an external magnetic field with appropriately chosen direction may cancel dynamic Stark frequency shift making the frequency of the clock transition insensitive to the strengths of both the laser and the magnetic fields. This can be attained for practically any laser frequency which is sufficiently distant from a resonance.