 Magnetic flux quantum

A magnetic flux quantum is the flux scaleassociated with a coherent degree of freedom of electric charge $q\ne 0$. Its Aharonov-Bohm phase on a loop enclosing magnetic flux $\Phi$ is $q\Phi /\hslash$; adding ${\Phi }_0$ changes that phase by one full turn.

For an electron, the magnitude of the charge is $e$, giving $h/e$. A conventional superconducting Cooper pair has charge magnitude $2e$, giving $h/(2e)$. The relevant charge must therefore be stated: a superconducting flux scale and a single-electron interference period differ by a factor of two.

In the magnetic translation algebra, translations along two lattice vectors commute when the enclosed unit-cell magnetic flux obeysThis is a condition on the algebra for the specified cell, not a claim that every externally applied magnetic flux must be quantized. The distinct magnetic flux spectrum of a quantum ring illustrates flux-periodic energy levels.

The magnetic flux quantum, often denoted as \(\Phi_0\), is a fundamental constant in quantum physics that describes the smallest possible unit of magnetic flux that can exist in a superconductor. It is particularly important in the context of superconductivity and quantum mechanics. The magnetic flux quantum is defined as: \[ \Phi_0 = \frac{h}{2e} \] where: - \(h\) is Planck's constant (approximately \(6.

TODO is there any relationship between this and the Josephson effect?

Experimental observation published as Experimental Evidence for Quantized Flux in Superconducting Cylinders.

This appears to happen to any superconducting loop, because the superconducting wave function has to be continuous.

Video "Superconducting Qubit by NTT SCL (2015)" suggests that anything in between gets cancelled out by a superposition of current in both directions.