Generation of Effective Field Gradient and Spin Current by a Flow of Liquid Helium-3

Abstract

The coupling of spin angular momentum and mechanical rotation is utilized for generating a spin current of nuclear spins of the liquid helium-3. A hydrodynamic flow in the liquid helium-3 provides a vorticity gradient which can be regarded as a gradient of effective magnetic field by the spin-rotation coupling. The effective field gradient generates a nuclear spin current owing to the Stern–Gerlach effect. We quantitatively estimate the magnitude of the field gradient based on the microscopic Boltzmann equation. The effective field gradient is large enough to be detected by NMR measurements.