Textures of Superfluid 3He-B in Applied Flow and Comparison with Hydrostatic Theory

TL;DR

This study measures the order parameter texture of rotating superfluid 3He-B at various temperatures and compares it with hydrostatic theory, confirming theoretical predictions and extracting key physical parameters.

Contribution

It provides experimental validation of hydrostatic theory for superfluid 3He-B and refines measurements of its energy gap, susceptibility, and phase transition under flow conditions.

Findings

Good agreement with hydrostatic theory when flow anisotropy is adjusted

Energy gap Delta(T) matches previous measurements, Delta(0)=1.97kBTc

Measurement of vortex numbers feasible down to 0.2Tc despite sensitivity loss

Abstract

Measurements of the order parameter texture of rotating superfluid 3He-B have been performed as a function of the applied azimuthal counterflow velocity down to temperatures of 0.2Tc. The results are compared to the hydrostatic theory of 3He-B. Good agreement is found at all measured temperatures and rotation velocities when the flow anisotropy contribution to the textural free energy is adjusted. This gives a superfluid energy gap Delta(T) which agrees with that measured by Todoshchenko et al., with Delta(0)=1.97kBTc at 29.0 bar. The B-phase susceptibility, longitudinal resonance frequency, and textural phase transition have been extracted from the measurements as a function of temperature and azimuthal counterflow velocity. Owing to decreasing absorption intensities the present measuring method, based on the line shape analysis of the NMR spectrum, loses its sensitivity with decreasing temperature. However, we find that in practice the measurement of vortex numbers and counterflow velocities is still feasible down to 0.2Tc.