Phys.org September 7, 2020
It was once assumed that the superconducting-to-normal transition caused by a magnetic field could not be reversed easily. However, it has been known for a long time from experiments that, if you remove the magnetic field, a current-carrying superconductor can, in fact, be returned to its previous state without loss of energy. Researchers in Japan proposed a new explanation for this phenomenon. In the superconducting state, electrons pair up and move in sync, but the true cause of this synchronized motion is due to Berry connection, characterized by the topological quantum number. It is an integer and if it is nonzero, current flows. Thus, this supercurrent can be switched off abruptly by changing this number to zero without Joule heating. The research may help lead to a future in which energy can be delivered from power plants to homes with perfect efficiency…read more. TECHNICAL ARTICLE
Credit: University of Tsukuba