Differential clock comparisons with a multiplexed optical lattice clock.

Area of Science:

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

Background:

• Optical atomic clocks have advanced timekeeping, metrology, and quantum science.
• Clock instability is often limited by the local oscillator, not the atoms themselves.

Purpose of the Study:

• To implement a novel 'multiplexed' one-dimensional optical lattice clock.
• To overcome the limitations imposed by local oscillator instability in optical clocks.
• To enable new applications in precision measurement and fundamental science.

Main Methods:

• Utilizing a one-dimensional optical lattice to trap spatially resolved strontium atom ensembles.
• Simultaneously interrogating multiple ensembles with a shared clock laser.
• Employing parallel readout and synchronous Ramsey interrogations for ensemble pairs.

Main Results:

• Achieved atom-atom coherence times of 26 seconds, a 270-fold improvement over atom-laser coherence.
• Demonstrated a relative instability of [Formula: see text] and a statistical uncertainty of 8.9 × 10⁻²⁰ after 3.3 hours.
• Established a miniaturized clock network with 6 ensembles and 15 pairwise comparisons, showing relative instabilities below [Formula: see text].
• Prepared spatially resolved, heterogeneous ensemble pairs of all four stable strontium isotopes.

Conclusions:

• The multiplexed clock design effectively bypasses local oscillator instability limitations.
• This technology enables high-precision isotope shift measurements and characterization of clock systematics.
• Paves the way for clock-based detectors for gravitational waves, dark matter, and new tests of relativity.