  Mesoscopic loop is proposed in many works as possible solid-state quantum
bit, i.e. two-state quantum system. The quantum oscillations of resistance and
of rectified voltage observed on asymmetric superconducting loops give evidence
of the two states at magnetic flux divisible by half of the flux quantum. But
our measurements of quantum oscillations of the critical current of these loops
have given results coming into irreconcilable contradictions with result of the
observations of the quantum oscillations of resistance.
