Analysis of strong-coupling parameters for superfluid He-3

Abstract

Superfluid He-3 experiments show strong deviation from the weak-coupling limit of the Ginzburg-Landau theory, and this discrepancy grows with increasing pressure. Strong-coupling contributions to the quasiparticle interactions are known to account for this effect and they are manifest in the five beta-coefficients of the fourth order Ginzburg-Landau free energy terms. The Ginzburg-Landau free energy also has a coefficient g(z) to include magnetic field coupling to the order parameter. From NMR susceptibility experiments, we find the deviation of g(z) from its weak-coupling value to be negligible at all pressures. New results for the pressure dependence of four different combinations of beta-coefficients, beta(345), beta(12), beta(245), and beta(5) are calculated and comparison is made with theory.