Anisotropic gap distortion due to superflow and the depairing critical current in superfluid 3He-B

We have calculated the pair-breaking critical current for superfluid 3He-B at all temperatures by taking into account the anisotropic distortion of the order parameter in the presence of superflow. We find that the component of the order parameter along the flow Δ/sub parallel/ is strongly reduced, while Δ/sub perpendicular/, the component perpendicular to the flow, slightly increases. The superfluid density rho/sub s/ has also been determined as a function of the superfluid velocity V/sub s/. Fermi liquid corrections are explicitly included and it is shown that these corrections lead to a drastic change in the functional dependence of Δ/sub parallel/, Δ/sub perpendicular/, rho/sub s/, etc., on v/sub s/. In contrast to this, the pair-breaking critical current is shown to be independent of the Fermi liquid corrections