US Patent 7443720 - Quantum state readout using cooper pair boxes

http://www.freepatentsonline.com/7443720.html

Cooper pairs refer to an attraction of two electrons that occurs in superconductive material at low temperature. This attraction makes electrons behave more like photons and are what produce the effects of zero resistance and magnetic field expulsion which characterize superconductivity. This patent based on a collaboration of Riken and NEC teaches the use of Cooper pair boxes to readout multiple states in a quantum computer. Claim 1 reads:

1. A quantum-state readout circuit comprising:

two Cooper pair boxes;

two capacitors that are coupled to the two Cooper pair boxes, respectively; and

reading means that is coupled to the capacitors and that comprises a single-electron transistor, wherein the two capacitors coupled to the two Cooper pair boxes have capacitances that are different from each other.