Quantum-Enhanced Dark Matter Search Using Cat States

Area of Science:

• Quantum physics
• Particle physics
• Astrophysics

Background:

• Quantum metrology offers advanced techniques for detecting weak signals, crucial for dark matter (DM) searches.
• Nonclassical cat states, macroscopic superpositions, present unique advantages for high-precision measurements.
• The application of cat states in DM searches has remained experimentally unexplored.

Purpose of the Study:

• To experimentally investigate the utility of four-component cat states in searching for dark photons, a potential dark matter candidate.
• To leverage quantum metrology techniques for enhanced sensitivity in DM detection.

Main Methods:

• Utilized a high-quality superconducting microwave cavity with four-component cat states.
• Employed a parametric sideband drive for active cavity frequency tuning.
• Performed dark photon searches and background subtraction across multiple frequency bins.

Main Results:

• Achieved an 8.1-fold enhancement in the signal photon rate.
• Constrained the dark photon kinetic mixing angle to ε<7.32×10⁻¹⁶ near 6.44 GHz (26.6 μeV).
• Demonstrated a sensitivity at the 10⁻¹⁶ level within a 100 kHz bandwidth.

Conclusions:

• This work represents the first experimental application of cat states for dark matter searches.
• The developed cat-assisted DM search and frequency-scanning techniques show substantial improvements over previous methods.
• The findings hold promise for future quantum-enhanced searches for new physics, including dark matter candidates.