Axion Dark Matter and Quantum Measurement: ABRACADABRA to DMRadio

The particle nature of dark matter remains one of the great open questions in physics. The axion has had a renaissance as a dark matter candidate as theoretical studies have improved our understanding of axion cosmology and advances in quantum sensing and cryogenics have opened new opportunities for detection. In this talk, I will review axion physics and motivate searches for < 1 micro-eV axions. I will then present the current results from ABRACADABRA and our vision for the DMRadio program including R&D on quantum sensors to enable a definitive search for axions throughout this < 1 micro-eV space.