Physical Review Letters
Josephson effect and quantum phase slippage in superfluids
Olivier Avenel, Eric Varoquaux
Abstract
We describe the operation of a hydromechanical resonator immersed in $^{4}\mathrm{He}$ and $^{3}\mathit{B}$ superfluids and opened on the main bath by two holes, a micro-orifice acting as a weak link and a long parallel channel. Transitions between adjacent quantum states differing by one hydrodynamic circulation quantum can be induced coherently, yielding a succession of steps arranged in a staircase pattern. In $^{3}\mathrm{He}$ at about 0.8 mK and 0 bar, a nearly ideal, nondissipative hydrodynamic Josephson effect can be observed.