“…A large number of recent experimental studies 1,2,3,4,5,6,7,8,9 indicates the presence of quasiparticles in superconducting single-charge devices at low temperatures. The operation of these devices, of which the best known is Cooper-pair box qubit, requires 2e-periodic dependence of the charge of the box on its gate voltage, and thus, an introduction of an unpaired electron(quasiparticle) in the Cooper-pair box (CPB) is a significant problem.…”