Active Frequency Measurement on Superradiant Strontium Clock Transitions

Area of Science:

• Atomic Physics
• Quantum Optics
• Quantum Measurement

Background:

• Superradiant emission in atomic ensembles is crucial for precision measurements.
• Previous experiments with strontium-87 atoms have demonstrated pulsed superradiant emission.

Purpose of the Study:

• To develop a theoretical framework for active frequency measurements of pulsed superradiant emission.
• To explain the dynamics of atomic ensembles with multiple transition frequencies.
• To compare theoretical predictions with experimental results for strontium-87 atoms.

Main Methods:

• Stochastic mean-field theory.
• Cavity quantum electrodynamics.
• Quantum measurement theory.

Main Results:

• The theory accurately reproduces experimental observations, including superradiant beats, noisy power spectra, and frequency uncertainty.
• A predicted short-term frequency uncertainty of 7×10⁻¹⁷/√τ is achieved.
• Active frequency measurements using superradiant transitions show performance comparable to current frequency standards.

Conclusions:

• The developed theory provides a robust description of active frequency measurements in superradiant systems.
• The findings suggest superradiant transitions can be utilized for high-precision frequency standards.
• The theory is applicable to other quantum dynamics and measurement processes, including steady-state superradiance and Raman lasing.