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

In superfluid He-3-B, the off-resonant coupling of the J = 2(-), M = +/- 1 order parameter collective modes to transverse current excitations stabiliz es propagating transverse waves with low damping for frequencies above that of the J = 2(-) modes. Right- (RCP) and left circularly polarized (LCP) tr ansverse modes are degenerate in zero field; however, a magnetic field with H parallel to q lifts this degeneracy giving rise to the acoustic analog o f circular birefringence and an acoustic Faraday effect for linearly polari zed transverse sound waves (Moores and Sauls, J. Low Temp. Phys. 91 (1993) 13). We present theoretical results for the temperature, pressure and field dependence of the Faraday rotation angle, and compare the theory with rece nt measurements (Lee ct al., Nature 400 (1999) 431). 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 He-3-B. (C) 2000 Elsevier Science B.V. All rights reserved.