Searching for Dark Matter with an Optical Cavity and an Unequal-Delay Interferometer

Area of Science:

• Experimental Physics
• Cosmology
• Particle Physics

Background:

• Ultralight oscillating dark matter (DM) models propose new interactions with Standard Model fields.
• Optical clocks offer high precision for detecting subtle physical variations.

Purpose of the Study:

• To experimentally search for ultralight oscillating dark matter using a novel fiber-delay-line optical clock.
• To constrain DM-Standard Model coupling constants in specific DM models.

Main Methods:

• A novel experiment comparing an optical cavity clock frequency at different times using a fiber delay line.
• Utilizing mechanical resonances of the optical cavity to enhance sensitivity.
• Analyzing experimental data for signatures of DM-induced oscillations.

Main Results:

• No evidence for ultralight oscillating dark matter in the mass range [4.1×10^{-11}, 8.3×10^{-10}] eV was found.
• Improved constraints on DM coupling constants by one order of magnitude for standard galactic DM models.
• Improved constraints by up to six orders of magnitude for relaxion DM models, especially at resonance.

Conclusions:

• The experiment sets new limits on ultralight oscillating dark matter and its interactions.
• The developed technique demonstrates sensitivity to DM couplings and can be further optimized.