On the electric activity of superfluid systems

TL;DR

This paper extends Keldysh's superfluidity theory for electron-hole gases to include pair polarizability, revealing how inhomogeneity and vortices induce electric effects in superfluid systems, with specific quantitative predictions.

Contribution

It generalizes the theory to account for pair polarizability and predicts electric charge in vortices within superfluid helium under magnetic fields.

Findings

Inhomogeneity induces a dipole moment proportional to density gradient.

Quantized vortices carry a measurable electric charge.

Charge density in superfluid helium under specified conditions is about 10^4e/cm^3.

Abstract

The Keldysh's theory of superfluidity of rarefied electron-hole gas is generalized to a case of possible pair polarizability. It was shown that inhomogeneity of the system leads to dipole moment which is proportional to the density gradient. The dipole moment appears also near boundaries of the system. It was determined that quantized vortices in a magnetic field carry a real electric charge. In He II at H=10 T and helium rotation velocity $10^2$ s$^{-1}$ the charge density is about $10^4e$ cm$^{-3}$, where $e$ is the electron charge.