Weyl and Dirac semimetals show anomalous quantum oscillations in the strong magnetic field (B) limit. Very surprisingly, the oscillations are periodic in ln B. We propose that the oscillations come from bound state spectra for Coulomb impurities that repeat when the binding energy is changed by a fixed factor, a signature of discrete scale invariance. The oscillations have now been seen in 4 Weyl semimetals: ZrTe₅, HfTe₅, TaAs, and Bi.

Prof. Robert Joynt obtained his Bachelor Degree from University of Toronto (Canada) in 1976 and PhD degree from the University of Maryland, College Park (USA) in 1982. After that he conducted his postdoctoral researches in Cavendish Laboratory (Cambridge) and Institut für Theoretische Physik (ETH-Zürich) in 1982 and 1984 respectively. He joined University of Wisconsin-Madison in 1986, and promoted to Full Professor of Physics Department in 1992. He then became the Department Chair from 2011-2014. Prof. Joynt is the Fellow of American Physical Society. His research has ranged from the quantum Hall effect to high-Tc superconductivity to neutron stars to quantum computing.