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

We propose a circuit comprising a linear array of three small-capacitance superconducting tunnel junctions with miniature resistors (R > R_Q = h/4e^2 = 6.5 kOhm) 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 Al-Cr Cooper pair R-pump is described.