SuperfluidB3in a weak link

We use the Ginzburg-Landau theory to consider the flow of superfluid ${}_{}{}^3{}_{}{}^{}\mathit{B}$ through a constriction (a ‘‘weak link’’) separating two bulk regions of superfluid. The boundary conditions that describe the applied flow (specified phase gradient) at the bulk ends differ from the analogous situation in a superconducting weak link (specified phase difference). We compute the critical current, which depends upon the width and length of the weak link.