Observation Of Dispersion In The J=2+ Collective Modes Of He-3-B By Nonlinear Acoustic Spectroscopy

TitleObservation Of Dispersion In The J=2+ Collective Modes Of He-3-B By Nonlinear Acoustic Spectroscopy
Publication TypeJournal Article
Year of Publication1992
AuthorsManninen, A. J., Alles H., Babkin A. V., Pekola J. P., and McKenzie Ross H.
JournalPhysical Review Letters
Volume68
Issue25
Pagination3725–3728
AbstractParametric excitation yields new results, which cannot be obtained by conventional linear spectroscopy, on the collective modes in superfluid He-3-B. In our ultrasonic experiments, performed in a chamber with four quartz crystals, we have excited the real squashing (J = 2+) modes by two simultaneous sound waves which are mutually either parallel, orthogonal, or antiparallel. Qualitatively these results are in agreement with the theoretical dispersion relation of the J = 2+ modes, and quantitatively we have been able to extract the collective-mode velocities from the line splittings in zero magnetic field.