Exotic Pauli spinors and magnetic flux quantization in a superconducting ring

Abstract

We develop the formalism of the exotic Pauli equation and establish an effective symmetry between standard and exotic Pauli spinors to describe magnetic flux quantization in a superconducting ring within the nonrelativistic framework. We show that, once the signs of the spatial and temporal topological terms are fixed consistently by the covariant exotic Dirac equation, this symmetry is exact at the level of the equations of motion, Lagrangians and currents, with no truncation of the exotic term and no condition on the time dependence of the topological phase. Upon deriving the flux quantization condition, we explicitly construct the composite matter-gauge unitary operator acting on the Hilbert space, which implements the symmetry at the quantum level (the gauge sector requiring the usual regularization).