The diffusion coefficient and the thermal diffusion ratio for 4He in liquid 3He at low temperatures were calculated by solving the Boltzmann equation; as derived from Fermi liquid theory. It was found that, as the temperature approached absolute zero, the thermal diffusion ratio approached a constant value and the diffusion coefficient varied as 1/T. Both were governed only by ao34, the l = 0 forward scattering amplitude. Because ao34 could be deduced from thermodynamic arguments, a strict test of the theory could made without making any assumptions about the dependence of the scattering amplitude upon momentum transfer. This made the present system unique among the applications of Fermi liquid theory.

T.G.Culman, D.O.Edwards, J.He: Physical Review Letters, 1995, 74[6], 948-51