Adiabatic quantum pumping at the Josephson frequency

Abstract

We analyze theoretically adiabatic quantum pumping through a normal conductor that couples the normal regions of two superconductor-normal-metal- superconductor Josephson junctions. By using the phases of the superconducting order parameter in the superconducting contacts as pumping parameters, we demonstrate that a nonzero pumped charge can flow through the device. The device exploits the evolution of the superconducting phases due to the ac Josephson effect, and can therefore be operated at very high frequency, resulting in a pumped current as large as a few nanoamperes. The experimental relevance of our calculations is discussed. © 2007 The American Physical Society.