Orientational effect of uniaxially deformed aerogel on the order parameter of superfluid $^3He$

Abstract

Effect of uniaxially-deformed aerogel on orientation of the order parameter of superfluid $^3He$ is considered. Approach used takes into account correlations in positions of particles forming aerogel. Calculations show that for the case of the B-like phase in the uniaxially-stretched aerogel deformation on the order of $10^{-2}\div10^{-4}$ is already strong enough to achieve orientation of the order parameter which is different from that required by magnetic field in bulk liquid. For the A-like phase in uniaxially-squeezed aerogel the order of magnitude of the orientational effect is estimated. It is shown that the correlations in positions of particles forming aerogel has stronger effect on the orientation of the order parameter than on the transition temperature.