Abstract: A non-linear superconducting quantum circuit comprising at least one resonant portion and an asymmetrical threaded superconducting quantum interference device connected to said at least one resonant portion galvanically, said non-linear superconducting circuit having a first mode with a first resonant frequency and a second mode with a second resonant frequency, the ratio between said first resonant frequency and said second resonant frequency being different from ½, said at least one resonant portion being configured with inductance and capacitance values of its symbolic representation which induce with said asymmetrical threaded superconducting quantum interference device said first mode and said second mode such that, said non-linear superconducting quantum circuit has zero-point fluctuations of the superconducting phase across the asymmetrical threaded superconducting quantum interference device for the first mode and the second mode which are superior or equal to 0.05 rad.

Abstract: An electromagnetically insulated superconducting qubit device comprising an electrical conductor having a substantially planar face and an artificial magnetic conductor having a substantially planar face facing the face of said electrical conductor, and one or more qubits made on or in one of said electrical conductor and said artificial magnetic conductor, the dimensions of the constituent elements of the artificial magnetic conductor and the distance separating the face of said electrical conductor and the face of said artificial magnetic conductor being chosen so as to make an electromagnetic band gap structure which comprises the frequencies of said qubits.