Cooper pair tunneling in circuits with substantial dissipation: the three-junction R-pump for single Cooper pairs

We propose a circuit (we call it R-pump) comprising a linear array of three smallcapacitance superconducting tunnel junctions with miniature resistors (R > R Q ≡ h/4e 2 ≅ 6.5 kΩ) attached to the ends of this array. Owing to the Coulomb blockade effect and the effect of dissipative environment on the supercurrent, this circuit enables the gate-controlled transfer of individual Cooper pairs. The first experiment on operating the R-pump is described.