Symmetry constraints on the spin dynamics of polarised He-3

The Leggett-Rice effect in liquid He-3 was proposed on the basis of Fermi l iquid interactions of the He-3 quasiparticles. Consideration of the interpa rticle interactions in polarised gaseous He-3 led, similarly, to spin rotat ion effects describable by a Leggett-Rice equation. In spin polarised solid He-3 an analogous effect has been proposed from a consideration of the int er-nuclear exchange interaction. We show, in this paper, that spin rotation behaviour of the Leggett-Rice type in all these systems may be understood as a consequence of symmetry constraints. (C) 2000 Elsevier Science B.V. Al l rights reserved.