Cancellation of systematic shifts in multi-ion optical clocks using dynamic decoupling


  Ravid Shaniv  
The Weizmann Institute of Science, Physics of Complex Systems

 

 The most precise clocks in the world use narrow optical transitions in atomic ions as frequency references. By probing N such ions simultaneously in a multi-ion clock, the frequency measurement's relative uncertainty can potentially reduce by cid:16759bf789311bfad142, corresponding to the standard quantum limit. However, when cid:16759bf7893da4bd5163and ions are trapped and form a Coulomb crystal, they can exhibit inhomogeneous shifts, making the promise of multi-ion uncertainty reduction not feasible. Two important inhomogeneous shifts are quadrupole shifts from the trapping potential and inhomogeneous Zeeman shifts from magnetic field gradient along the crystal. In this talk, I will introduce a method for clock operation, incorporating active RF control that cancels the quadrupole and linear Zeeman shift locally for each ion. This active cancellation falls under the quantum information notion of continuous dynamical decoupling. I will show results proving that the ions exhibit homogeneous transition frequency using correlation spectroscopy. The cancellation of these shifts may pave the path for a multi-ion clock, benefiting from the favorable controllability of ions, with improved clock stability.