Surface coupling to collective and single-particle spin modes in normal 3He

Abstract

The authors propose a simple technique for probing the single-particle and collective excitations in normal /sup 3/He via a standing magnetic surface wave of arbitrary /omega/ and fixed k generated by a meander-line coil. An analytic treatment of the Landau-Sillin equation enables them to calculate the power absorption spectrum, which displays singularities associated with the 1 = 0 spin mode and a Doppler-shifted spin resonance (DSSR) of the single-particle excitations. Experimental measurement of the spectrum would determine the Landau parameters (F/sub 0//sup a/, F/sub 1//sup a/) with a spectroscopic precision. Furthermore, observation of the DSSR thresholds would provide an independent determination of the Fermi velocity v and F/sub 0//sup a/. Finally, a possibility of exciting higher, 1 /ge/ 1, spin modes is briefly mentioned in the framework of an extended Leggett-Rice equation.