SLAC National Accelerator Laboratory - 2010 March 15
Dynamical axion field in topological magnetic insulatorsDesktop experiments could point the way to dark matter discovery, complementing grand astronomical searches and deep underground observations. According to recent theoretical results, small blocks of matter on a tabletop could reveal elusive properties of the as-yet-unidentified dark matter particles that make up a quarter of the universe, potentially making future large-scale searches easier. This finding was announced today by theorists from the Stanford Institute for Materials and Energy Science (SIMES), a joint institute of the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University, at the American Physical Society meeting in Portland, Oregon.
- Nature Physics | 07 March 2010 | doi:10.1038/nphys1534
Rundong Li, Jing Wang, Xiao-Liang Qi1 & Shou-Cheng Zhang
Axions are weakly interacting particles of low mass, and were postulated more than 30 years ago in the framework of the Standard Model of particle physics. Their existence could explain the missing dark matter of the Universe. However, despite intensive searches, axions have yet to be observed. Here we show that magnetic fluctuations of topological insulators couple to the electromagnetic fields exactly like the axions, and propose several experiments to detect this dynamical axion field. In particular, we show that the axion coupling enables a nonlinear modulation of the electromagnetic field, leading to attenuated total reflection. We propose a new optical-modulator device based on this principle.