Axions that couple to nuclear spins via the axial current interaction can be both produced and detected using nuclear magnetic resonance (NMR) techniques. In this scheme, nuclei driven by a real oscillating magnetic field in one device act as an axion source, which can drive NMR in a nearby spin-polarized sample interrogated with a sensitive magnetometer. We study the prospects for detecting axions through this method and identify two key characteristics that result in compelling detection sensitivity. First, the gradient of the generated axion field can be substantial, set by the inverse distance from the source. In the near zone, it reduces to the inverse of the source’s geometric size. Second, because the generated axion field is produced at a known frequency, the detection medium can be tuned precisely to this frequency, enabling long interrogation times. In this talk, I will present a calculation of experimental sensitivity. As I will show, a pair of 10-centimeter-scale NMR devices operating over a one-hour integration time can already surpass existing astrophysical bounds on the axion-nucleon coupling, including those from star cooling. These dual NMR configurations can probe a wide range of axion masses, up to values comparable to the inverse distance between the source and the sensor.

Biography

Dr. Fengwei Yang was a joint post-doctoral associate at the University of Florida and University of Notre Dame and is starting the new postdoc position in the JGU Mainz in September 2026. He completed his bachelor’s degree in science at Nanjing University in 2017. In 2023, he earned his Ph.D. in Physics from the University of Utah. His research interests lie in the field of high energy phenomenology, with a focus on using experiments to probe new physics beyond the Standard Model (SM). He has been working on several different approaches to looking for axions and studying axion phenomenology, including axion strings, axion clouds, and NMR production and detection of non-relic axions.

Inviter: Ning-Qiang Song