The reverse AC-Josephson effect in 3He-B

No Heading We have investigated ³He Josephson currents under an externally applied ac-pressure modulation. The ³He-flow was driven by the motion of a flexible membrane through an array of 65 by 65 holes of 150 nm size in a 50 nm thick SiN wall. The membrane was deflected electrostatically. If a sinusoidal modulated electrostatic force was applied to the membrane, we could observe phase locking of the Josephson oscillations to the external ac-drive. As a result, a zero net flow through the weak link was observed while the membrane was stuck for many seconds at a non zero pressure position. For this pressure the Josephson frequency matched the ac-drive frequency. We could resolve the dynamics which led to this trapped, phase locked state. The dynamics looked quite similar to dynamics which took place when the system ended up in Helmholtz oscillations at the zero pressure difference equilibrium state.PACS numbers: 67.57.De, 67.57.Fg, 74.50.+r, 85.25.Cp