Search for superfluid Josephson effect

The superfluid analogue of the Josephson effect in superconductors is based on the weak coupling between two adjacent superfluid reservoirs. It relates their pressure difference to a frequency and promises the realization of high-precision sensors for pressure and rotation. Ion tracks provide obstacles sufficiently small to interfere with superfluids. These so-called ''weak links'' represent potential barriers through which tunneling occurs between the two neighbouring superfluid reservoirs. The experimental status is described. (author)