QMSI: Prof. Stefan Knirck, Harvard University

 Hunting Axion Dark Matter with Novel Resonators and Quantum Sensing 

The nature of Dark Matter (DM) is one of the most challenging unsolved mysteries of modern physics. Axions are excellent DM candidates and would also explain why the neutron’s electric dipole moment is vanishingly small. Under an external magnetic field axions can convert to photons which can be enhanced in a resonator cavity. We first present the world-leading ADMX (Axion Dark Matter eXperiment) which has excluded QCD axion DM for about an octave in mass range around 4μeV (1GHz) and is poised to search up to 16μeV (4GHz). Yet, about 6 orders of magnitude of higher masses, up to eV (infrared), remain unprobed. At these masses resonant cavities become infeasible. We discuss R&D on novel resonator technology for this range, including MADMAX (Magnetized Disk and Mirror eXperiment) and BREAD (Broadband Experiment for Axion Detection). We highlight first prototype results, including the world’s first search for axion-like particles with a dish antenna. We outline the research program of our new group at Harvard leveraging cutting-edge quantum sensing and cross-disciplinary collaboration for axion discovery. 

Speakers

• 

  Stefan Knirck

  Assistant Professor of Physics
  Harvard University

  Knirck studied physics in Heidelberg and built what is likely the world’s first dark photon dark matter direct detection experiment in the meV range at The University of Tokyo and University of Fukui in 2016. He obtained his Ph. D. summa cum laude at the Max-Planck-Institute of Physics and the Technical University of Munich in 2020 for studies on MADMAX. His thesis was recognized as “Best Ph.D. thesis of 2020” within his Collaborative Research Center, SFB1258. After graduation, Knirck worked as a research associate at Fermilab making essential contributions to ADMX. Moreover, he led the design, build and run of the first BREAD prototype. His work leveraging synergies between all three collaborations was recently honored with the DESY International Fellowship Award. Knirck joined Harvard as an assistant professor in January 2025.