Reversible superconducting-normal phase transition in a magnetic field and the existence of topologically protected loop currents that appear and disappear without Joule heating

Division of Quantum Condensed Matter Physics, Center for Computational Sciences, University of Tsukuba Tsukuba, Ibaraki 305-8577, Japan

Received: 5 June 2020
Accepted: 23 July 2020

Abstract

Reversible superconducting-normal phase transition in a magnetic field indicates that the supercurrent generation mechanism needs to explain how the kinetic energy is transferable to the magnetic field energy without dissipation, and vice versa. This energy transfer is impossible within the standard theory due to the production of the Joule heat. We argue that this transformation becomes possible if the theory is so modified that supercurrent generation is due to a nontrivial Berry connection arising from many-body effects. In this case, supercurrent is a collection of topologically protected loop currents, and stopping of it is achieved by making the Berry connection trivial.