The characteristic response curve, I(ΔP), of a ³He weak link

We report measurements of the mass current as a function of pressure difference, I(ΔP), for superfluid ³He flowing through an aperture whose dimensions are on the order of the temperature dependent coherence length. The goal of the experiment is to see to what extent this weak link behaves like a simple Josephson junction. A model has been developed which predicts I(ΔP) for the case where the weak link is analyzed as a series connection of resistance, inductance and ideal Josephson junction. This model is found to be inadequate to explain the central feature of the data, i.e. the current increases monotonically with ΔP.