The London moment: what a rotating superconductor reveals about superconductivity

arxiv: 1310.3834 (Los Alamos). Physica Scripta 89, 015806 (2014).

The London moment is the magnetic moment acquired by a rotating superconductor. We propose that the London moment reveals the following fundamental properties of the superconducting state: (i) superconductors (unlike normal metals) know the sign of the charge carriers, (ii) the superconducting charge carriers are free electrons, (iii) electrons are expelled from the interior to the surface in the transition to the superconducting state, (iv) superfluid electrons occupy orbits of radius 2λL (λL=London penetration depth), and (v) a spin curren t exists in the ground state of superconductors. These properties are consistent with the Meissner effect, however the Meissner effect does not directly reveal the sign of the charge carriers nor the fact that the carrier's mass is the free electron mass nor the fact that a spin current exists in superconductors. Note also that within the BCS theory of superconductivity none of the key properties of superconductors listed above are predicted. Instead, these properties are predicted by the theory of hole superconductivity.