We present a design for a charge qubit, and an associated quantum sample and hold measurement scheme. Using arrays of superconducting. islands, connected by tunable tunnel junctions, we can sample the charge states by turning off the Josephson coupling, and then hold a Cooper pair on an island for a very long time. This allows for a slow readout using a conventional weakly coupled low-frequency single-electron transistor.
2002. Vol. 65, no 2