Chris Overstreet received his PhD from Stanford University in 2020 and was a postdoctoral fellow at Stanford from 2021 to 2023. Now he is an assistant professor of physics at Johns Hopkins University. His research interests are centered on using atomic, molecular, and optical systems to gain insight into fundamental physics.
Presentation Title:
Ytterbium atom interferometry for dark matter searches
Presentation Abstract:
I will discuss the projected sensitivity of a laboratory-scale ytterbium atom interferometry experiment to scalar, vector, and pseudoscalar dark matter signals. A frequency ratio measurement between two electronic transitions in ytterbium enables a search for variations of the fine-structure constant that could surpass existing limits by a factor of 100 in the mass range 10^−22 eV to 10^−16 eV. Differential accelerometry between ytterbium isotopes yields projected sensitivities to scalar and vector dark matter couplings that are stronger than the limits set by the MICROSCOPE equivalence principle test, and an analogous measurement in the MAGIS-100 long-baseline interferometer would be more sensitive than previous bounds by factors of 10 or more. A search for anomalous spin torque in MAGIS-100 is projected to reach similar sensitivity to atomic magnetometry experiments. I will also discuss strategies for mitigating the main systematic effects in each measurement. These results indicate that improved dark matter searches with ytterbium atom interferometry are technically feasible.