Weyl Fermion (IMAGE) Princeton University Caption A detector image (top) signals the existence of Weyl fermions. The plus and minus signs note whether the particle's spin is in the same direction as its motion -- which is known as being right-handed -- or in the opposite direction in which it moves, or left-handed. This dual ability allows Weyl fermions to have high mobility. A schematic (bottom) shows how Weyl fermions also can behave like monopole and antimonopole particles when inside a crystal, meaning that they have opposite magnetic-like charges can nonetheless move independently of one another, which also allows for a high degree of mobility. Credit Image by Su-Yang Xu and M. Zahid Hasan, Princeton Department of Physics Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.