Operating a Multi-Ion Clock with Dynamical Decoupling.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Metrology
• Precision Measurement

Background:

• Multi-ion optical clocks face challenges from inhomogeneous frequency shifts, limiting their stability and accuracy.
• Dominant shifts include electric quadrupole and linear Zeeman effects, which are critical to mitigate for high-precision measurements.

Purpose of the Study:

• To study and characterize a quasicontinuous dynamical decoupling (QCDD) scheme for suppressing frequency shifts in multi-ion optical clocks.
• To demonstrate the effectiveness of the QCDD scheme in mitigating electric quadrupole and linear Zeeman shifts.
• To evaluate the systematic shifts associated with the radio-frequency drive in the QCDD scheme.

Main Methods:

• Implementation of a quasicontinuous dynamical decoupling scheme using chains of up to 7 ^{88}Sr^{+} ions.
• Characterization of frequency shifts, specifically electric quadrupole and linear Zeeman shifts.
• Evaluation of systematic frequency uncertainty contributions from the radio-frequency drive.

Main Results:

• Demonstrated suppression of frequency shifts by over 3 orders of magnitude.
• Achieved relative frequency inhomogeneity below 7×10^{-17} in ^{88}Sr^{+} ion chains.
• Quantified the systematic shift from the RF drive to be below 10^{-17} relative uncertainty.

Conclusions:

• The quasicontinuous dynamical decoupling scheme effectively suppresses dominant frequency shifts in multi-ion optical clocks.
• This approach offers a pathway to multi-ion clocks with improved stability and accuracy comparable to single-ion clocks.
• Further improvements in the RF drive are possible, potentially enhancing clock performance even more.