Axion dark matter detection with cold molecules

by Surjeet Rajendran (Johns Hopkins University, Baltimore)

Tuesday 31 May 2011, 17:15 → 18:15 Europe/Berlin

Auditorium (MPI fuer Physik)

Current techniques cannot detect axion dark matter over much of its parameter space, particularly in the theoretically well-motivated region where the axion decay constant lies near the GUT and Planck scales. We suggest a novel experimental method to search for the QCD axion dark matter in this region. The axion field oscillates at a frequency equal to its mass when it is a component of dark matter. These oscillations induce time varying CP-odd nuclear moments, such as electric dipole and Schiff moments. The coupling between internal atomic fields and these nuclear moments gives rise to time varying shifts to atomic energy levels. These effects can be enhanced by using elements with large Schiff moments such as the light Actinides, and states with large spontaneous parity violation, such as molecules in a background electric field. While challenging, this energy shift may be observable in a molecular clock configuration with technology presently under development. A discovery in such an experiment would not only reveal the nature of dark matter and confirm the axion as the solution to the strong CP problem, it would also provide a glimpse of physics at the highest energy scales, far beyond what can be directly probed in the laboratory.