In quantum mechanics, the motion of an electron is represented by a wave function, and the basic physical quantity in an electromagnetic field is a gauge potential rather than an electric or magnetic field.Associate Professor Koizumi applied this to the calculation of induced electromotive force, described the motion of electrons with a wave function, and at the same time, used an electromagnetic field as a gauge field and used gauge potential instead of electric and magnetic fields.At that time, when the degree of freedom of the gauge was fixed under the condition of energy minimization, the phase factor of the wave function representing the quantum state of the electron in the moving lead wire was translated by the Lorentz force in the direction along the electron lead wire. On the other hand, it was found that it can be regarded as a time-dependent gauge potential that produces an electric field.

　That is, this former view corresponds to the method using Lorentz force, the latter corresponds to the method using Faraday's law of electromagnetic induction, and the strange agreement between the two essentially different methods seen in classical electromagnetism is It was found that the result was connected by the duality of the phase factor of the wave function representing the quantum state of the electron.

　This result not only provided a theoretical answer to the concordance that was thought to be a coincidence, but also by applying the idea of ​​the duality of the phase factor to the wavefunction of the superconducting state, the superconducting qubit. It is said that it also contributes to the development of quantum computers using.

Paper information:[Journal of Superconductivity and Novel Magnetism] Flux Rule, U (1) Instanton, and Superconductivity