ADMX-SIDETRAC: A quantum-enhanced two-cavity haloscope for improving high-mass axion detection

Axions are a wave-like dark matter candidate that can be detected with a cavity haloscope. The sensitivity of a haloscope significantly decreases at higher axion masses due to decreasing cavity volume, increasing thermal noise, and degradation of the cavity quality factor. Multi-cavity haloscopes can mitigate this partially, but this increases the instrument's operational complexity. ADMX-SIDETRAC is an R&D multi-cavity haloscope sited at PNNL poised to solve these issues by jointly exploring several emerging technologies. It consists of two cavities operating in a 14T magnet targeting axions near 6 GHz. AI/ML controls may simplify and optimize the operations of the multi-cavity system. Magnetic-field-tolerant KITWPAs may enable amplification with low magnetic shielding. A qubit photon-counting readout could evade the standard quantum noise limit. Ongoing developments of this haloscope are discussed.