FERMI-LIQUID PROPERTIES OF HE-3-HE-4 MIXTURES

We calculate microscopically the spectrum of a He-3 impurity atom movi ng in He-4, determine the Fermi-Liquid interaction between He-3 atoms and then calculate the pressure and concentration dependence of the ef fective mass and the magnetic susceptibility. The long wavelength limi t of the spectrum defines the hydrodynamic effective mass. When k grea ter than or equal to 1.7 Angstrom(-1) the motion of the impurity is da mped due to the decay into a roton and a lour energy impurity mode. Th e calculations of the Fermi-Liquid interaction are based on correlated basis functions (CBF); the relevant matrix elements are determined by the Fermi hypernetted-chain theory. Our theoretical effective masses agree well with recent measurements,(1,2) but our analysis suggests a new extrapolation to the zero-concentration limit. With that effective mass we also find a good agreement with the measured(3) Landau parame ter F-0(a).