Improving Short-Term Stability in Optical Lattice Clocks by Quantum Nondemolition Measurement.

Area of Science:

• Quantum physics
• Atomic clocks
• Metrology

Background:

• Quantum nondemolition (QND) measurements are crucial for high-precision atomic clocks.
• Current optical lattice clocks possess QND measurement capabilities.
• Improving clock stability beyond the standard quantum limit is a key challenge.

Purpose of the Study:

• To propose a novel multimeasurement estimation protocol for QND measurements in Rabi clock interferometers.
• To enhance the precision and stability of atomic clocks.
• To analyze the trade-offs between measurement sensitivity and back-action.

Main Methods:

• Exploiting correlations between multiple nondestructive measurements of a coherent spin state.
• Developing a Gaussian estimator for clock laser detuning.
• Deriving an analytic expression for protocol sensitivity.
• Optimizing the protocol using experimental parameters.

Main Results:

• Achieved an improvement of 7.9 dB in clock stability compared to the standard quantum limit.
• Demonstrated the protocol's suitability for state-of-the-art optical lattice clocks.
• Analyzed the measurement back-action effects on the atomic state.

Conclusions:

• The proposed multimeasurement protocol offers a significant advancement in atomic clock precision.
• The method effectively leverages QND measurement capabilities for enhanced metrology.
• Further research can explore minimizing measurement back-action for even greater accuracy.