Searching for Interactions of Ultra-Light Axion-Like Dark Matter

The nature of dark matter is one of the most important open problems in modern physics. Alex Sushkov and Michael Romalis are pursuing an experimental program to search for ultra-light dark matter in the form of axion-like particles. Collectively, the experimental efforts at Boston University and Princeton will search over a broad range of ultra-light dark matter masses and are sensitive to the three possible interactions of axion-like particles: the electromagnetic coupling, the axion-gluon coupling and the axion-wind coupling. The experiments rely on precision magnetometry and magnetic resonance methods, which makes technical and scientific collaboration between the research teams extremely valuable. This research effort will improve existing limits on axion dark matter as well as develop new experimental techniques for future searches with greatly improved sensitivity.

Alex Sushkov is currently an assistant professor at Boston University, employing magnetic resonance and precision magnetometry tools to search for axion-like dark matter and using NV centers in diamond for nanoscale studies of dynamical phenomena in magnetic materials and spin systems. He received his Ph.D. from the University of California, Berkeley, where he developed methods for atomic magnetometry with room-temperature alkali-vapor cells and in cryogenic buffer-gas cells, in addition to being an active member of the Oak Ridge National Laboratory neutron electric dipole moment (EDM) collaboration, performing measurements of the electro-optical Kerr constant of superfluid liquid helium. He then had positions at Yale and Harvard Universities, where he continued work on precision experiments studying fundamental physics, including the Casimir effect, permanent electron EDM and NMR with single-spin resolution.

Michael Romalis is a professor of physics at Princeton University specializing in the use of spin-polarized atoms for fundamental physics and sensing applications. His group has developed a number of new techniques for magnetometry, inertial rotation sensing and tests of fundamental symmetries. He received his Ph.D. from Princeton and worked at the University of Washington on searches for CP violation using Hg atoms. Most recently his group has set best limits on axion-mediated spin-dependent forces and violations of Lorentz invariance. He is a fellow of the American Physical Society, recipient of Packard Fellowship and APS Francis M. Pipkin award.