Viscosity Increase as a Function of Polarization in LiquidHe3

Abstract

The polarization dependence of the viscosity of spin-polarized liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ has been determined in the temperature range $75<T<\mathrm{}300\mathrm{}$ mK and the polarization range $\Delta <0.35\mathrm{}$. We find an increase in the viscosity, which can be described as $\eta \propto 1+\alpha {\Delta }^2$ with $\alpha =4.0\mathrm{}\pm 1.5$, at a pressure of 27 bars. This increase is expected from the ratio of the cross sections for $s$-wave and $p$-wave scattering. It is rather surprising, however, that there is no temperature dependence of $\alpha$.