Physical Review Letters
Coupling of zero sound to the real squashing mode in rotating B3
Riitta H. Salmelin, Jukka P Pekola, Antti J. Manninen, Kenji Torizuka, M. Berglund, Jukka M. Kyynarainen, Olli V. Lounasmaa, George Tvalashvili, O. V. Magradze, Eric Varoquaux, Olivier Avenel, V. P. Mineev
Abstract
Rotation of superfluid $^{3}\mathit{B}$ in an magnetic field enhances the coupling of the nonzero ${\mathrm{m}}_{\mathrm{J}}$ substrates of the real squashing collective mode to the zero sound, and the fivefold line splitting becomes observable even when H is parallel to \ensuremath{\Omega} and to the direction of sound propagation. Equilibrium vortex lattices and vortex-free states can be distinguished by their characteristic absorption spectra. The dependence of the sound attenuation on the angular velocity in magnetic fields up to 32 mT is reported; the data are qualitatively compared with theory.