Researchers in Japan have used a supercomputer to help us understand exactly what happens when a material undergoes the transition from the metallic phase to the insulator phase. The analysis by scientists from the RIKEN Advanced Institute for Computational Science (AICS) in Kobe, published in the journal Physical Review X, shows that there is a direct movement between the two phases, and that this behavior coincides with the loss of mass of the electrons - Dirac electrons - in the materials as they become correlated with one another. The study has fundamental implications for condensed matter physics and may lead the way to novel materials with useful electrical and magnetic properties.