Optimal Electromagnetic Searches for Axion and Hidden-Photon Dark Matter

Understand

Direct-detection searches for axions and hidden photons are playing an increasingly prominent role in the search for dark matter.

• In this work, we derive the properties of optimal electromagnetic searches for these candidates, subject to the Standard Quantum Limit (SQL) on amplification.
• We show that a single-pole resonant search may possess substantial sensitivity outside of the resonator bandwidth and that optimizing this sensitivity may increase scan rates by up to five orders of magnitude at low frequencies.
• Additional enhancements can be obtained with resonator quality factors exceeding one million, which corresponds to the linewidth of the dark matter signal.