Resonator with Ultrahigh Length Stability as a Probe for Equivalence-Principle-Violating Physics.

Area of Science:

• Physics
• Metrology
• Cosmology

Background:

• Investigating the long-term dimensional stability of matter is crucial for fundamental physics.
• Optical resonators offer high precision for measuring physical length and time standards.

Purpose of the Study:

• To assess the dimensional stability of a crystalline silicon optical resonator over one year.
• To constrain hypothetical effects of universal expansion on physical rulers and atomic clocks.
• To derive bounds for space-time fluctuations and violations of local position invariance.

Main Methods:

• Operating a crystalline silicon optical resonator at 1.5 K continuously for over a year.
• Comparing the resonator's frequency (f_res) with a GPS-monitored hydrogen maser.
• Analyzing resonance frequency drift over a 163-day interval after initial settling.

Main Results:

• A mean fractional drift magnitude of |f_res^{-1}df_{res}/dt|<1.4×10^{-20}/s was observed.
• This bound rules out, to first order, a differential effect of the Universe's expansion on rulers and atomic clocks.
• Constraints were placed on violations of the principle of local position invariance and space-time fluctuations.

Conclusions:

• Crystalline silicon optical resonators exhibit remarkable long-term dimensional stability.
• The study provides stringent limits on fundamental physics theories, including cosmology and general relativity.
• This work advances the precision of timekeeping and metrology for future scientific endeavors.