Axion Dark Matter eXperiment at High Frequency (ADMX-HF)

Yale University, New Haven CT

Investigators

Abstract

All astrophysical and cosmological data now point convincingly to a large component of Cold Dark Matter (CDM) in the Universe, for which a light axion is a well-motivated candidate. It has long been known that if axions are a primary constituent of the dark matter of our own Milky Way halo, they may be detected through their conversion into a narrow-band microwave signal by an apparatus consisting of a microwave-cavity resonator permeated by a magnetic field. Since 1996, the Axion Dark Matter eXperiment (ADMX) has been searching for axions, achieving sensitivities well within the band of axion models, excluding masses in the few micro-eV range. With recent technological advances, it is now possible to extend these measurements to higher frequencies. This award will enable the Yale group to join the ADMX collaboration and to build and operate a second microwave cavity experiment, ADMX at High Frequencies (ADMX-HF), to probe the 2-20 GHz (~8 to 80 micro-eV) range. This brackets the mass of the axion which corresponds to saturation of the matter density of the universe (~ 20 micro-eV). ADMX as "one experiment, two sites" will thus be able to pursue a two-prong strategy, simultaneously pushing downwards in the axion-photon coupling and upwards in mass. In Broader Impacts, ADMX has already proven to be a driver of leading-edge technology; NSF supported the development of the near-quantum limited SQUID amplifiers for ADMX more than a decade ago, which quickly spun off to become a critical piece of IARPA's (Intelligence Advanced Research Projects Activity) roadmap in quantum computing. ADMX-HF can similarly be expected to draw from the deep quantum electronics competency at Yale to provide new innovations benefiting basic science and security. The PI has a long history of employing undergraduates to work on his research.