Transportable Optical Lattice Clock with 7×10^{-17} Uncertainty

Area of Science:

• Atomic, Molecular, and Optical Physics
• Metrology
• Geodesy

Background:

• Optical atomic clocks offer superior precision over microwave clocks.
• Transportable optical clocks are crucial for disseminating precise time scales and enabling new scientific applications.
• Existing transportable clocks have limitations in uncertainty and instability.

Purpose of the Study:

• To develop and characterize a highly stable and accurate transportable optical clock (TOC) using strontium-87 (Sr-87).
• To assess the TOC's performance for applications like chronometric leveling and intercontinental clock comparisons.
• To demonstrate the potential for reducing systematic uncertainty to below 1x10^-17.

Main Methods:

• Development of a Sr-87 based transportable optical clock.
• Characterization of the TOC against a stationary lattice clock.
• Autonomous operation in a climate-controlled vehicle trailer.
• Evaluation for chronometric leveling and clock network applications.

Main Results:

• Achieved a systematic uncertainty of 7.4x10^-17, currently limited by statistical fluctuations.
• Demonstrated an instability of 1.3x10^-15/sqrt[τ].
• Confirmed potential to reduce systematic uncertainty below 1x10^-17.
• Reported best-in-class uncertainties and instabilities for a transportable clock.

Conclusions:

• The developed Sr-87 TOC represents a significant advancement in portable high-precision timekeeping.
• The clock is suitable for demanding applications including chronometric leveling and global optical clock synchronization.
• This technology is a key step towards space-borne optical clocks and a redefinition of the SI second.