Experimental investigation of two-phonon absorption by the real squashing mode in superfluid 3He-B

Research output: Contribution to journalArticle


  • J.P. Pekola

  • K. Torizuka
  • A. J. Manninen
  • H. Alles
  • O. V. Lounasmaa

Research units


We report on investigations of a nonlinear parametric excitation of the real squashing (RSQ) collective mode in superfluid 3He-B. Two-phonon absorption (TPA) at fs + fp = frsq has been observed by two coincident zero sound pulses, with the signal and the pump wave frequencies at fs and fp, respectively. We have also discovered and studied the Zeeman splitting of TPA in a magnetic field, which is a characteristic feature of the J = 2+ mode in the linear response regime. The dependence of the mode frequency on the magnitude of the wave vector has been investigated; this can be done easily in parametric measurements only. In our earlier, preliminary observations, the coupling of the RSQ mode by TPA was weaker than theory predicted; the discrepancy has now been systematically studied and clarified.


Original languageEnglish
Pages (from-to)238-243
Number of pages6
JournalPhysica B: Condensed Matter
Issue number1-4
Publication statusPublished - 2 May 1992
MoE publication typeA1 Journal article-refereed

    Research areas

  • nonlinear excitation, real squashing mode, superfluid 3He-B

ID: 4393993