Seeking the unseen: The Axion Dark Matter eXperiment (ADMX)*

The nature of the dark matter in the Universe is one of the most compelling questions in all of science. Dark matter makes up roughly 85\% of the mass in the universe and we don't know what it is. It interacts extremely weakly with ordinary matter and energy making detection very challenging. The axion, a very well-motivated candidate for the dark matter, can be detected by conversion to microwave photons in a strong magnetic field; this process is the basis of many searches for axions and axion-like particles. The Axion Dark Matter eXperiment (ADMX) is conducting a search for axions within the dark-matter halo of our Galaxy. The ADMX experiment employs a large-volume superconducting magnet, a high-$Q$ tunable microwave cavity, an ultrasensitive SQUID microwave amplifier, and a high-performance dilution refrigerator to enable noise backgrounds in the mK temperature range. This ``Generation 2'' ADMX detector has reached the sensitivity to detect axions even for the most-weakly-coupled theories. The ADMX detector has completed two science runs at this design sensitivity. There were no detections and the search continues with a third science run. The resulting limits on axion mass and coupling, the prospects for the ongoing search, and the outlook for the future will be discussed.