Magneto-acoustic rotation of transverse waves in 3He-B

TL;DR

This paper investigates the magneto-acoustic Faraday effect in superfluid 3He-B, analyzing how magnetic fields influence transverse sound wave polarization and providing insights into collective modes and pairing correlations.

Contribution

It offers a theoretical framework for the Faraday rotation in 3He-B, connecting it with collective mode properties and experimental measurements.

Findings

Measured Faraday rotation angles across temperature, pressure, and field.

Determined the Lande g-factor for J=2- modes.

Provided new insights into f-wave pairing correlations.

Abstract

In superfluid 3He-B the off-resonant coupling of the J=2-, M=+/- 1 order parameter collective modes to transverse current excitations stabilizes propagating transverse waves with low damping for frequencies above that of the J=2- modes. Right- (RCP) and left circularly polarized (LCP) transverse modes are degenerate in zero field; however, a magnetic field with H || q lifts this degeneracy giving rise to the acoustic analog of circular birefringence and an acoustic Faraday effect for linearly polarized transverse sound waves. We present theoretical results for the temperature, pressure and field dependence of the Faraday rotation angle, and compare the theory with recent measurements. The analysis provides a direct measurement of the Lande' g-factor for the J=2- modes, and new information on the magnitude of f-wave pairing correlations in 3He-B.