Is magnetic flux quantized inside a solenoid?

TL;DR

The paper clarifies misconceptions about magnetic flux quantization, emphasizing that it applies to superconducting rings but not necessarily to long solenoids, and explains how to avoid related confusion.

Contribution

It elucidates the distinction between flux quantization in superconducting rings and solenoids, correcting common misconceptions in quantum mechanics textbooks.

Findings

Flux quantization applies to superconducting rings, not necessarily to solenoids.

The paper explains the origin of confusion in textbook descriptions.

Provides guidance to avoid misconceptions about flux quantization.

Abstract

In some textbooks on quantum mechanics, the description of flux quantization in a superconductor ring based on the Aharonov-Bohm effect may lead some readers to a (wrong) conclusion that flux quantization occurs as well for a long solenoid with the same quantization condition in which the charge of cooper pair $2e$ is replaced by the charge of one electron $e$. It is shown how this confusion arises and how can one avoid it.