A method and a device for preparing an inductance element, an inductance element, and a superconducting circuit are provided. The method includes acquiring a compound for preparing an inductance element, a superconducting coherence length and a magnetic field penetration depth of the compound meeting a preset condition; and annealing the compound to cause decomposition between a non-superconductor phase and a superconductor phase in the compound to generate the inductance element, the kinetic inductance of the inductance element being greater than the geometric inductance of the inductance element.

A traveling wave superconducting parametric amplifier is provided. The traveling wave superconducting parametric amplifier includes a chain of superconducting elements having a nonlinear kinetic inductance connected in series, said superconducting elements being deposited on a substrate. The traveling wave superconducting parametric amplifier also includes a dielectric layer of sub-micrometer thickness deposited on the substrate and covering said superconducting elements, and a conductive layer forming a ground plane deposited on top of the dielectric layer, the superconducting elements and the ground plane forming a microstrip-type transmission line. A method for producing such a traveling wave parametric amplifier is also provided.

High-saturation power Josephson ring modulators and fabrication of the same are provided. A Josephson ring modulator can comprise a plurality of matrix junctions. Matrix junctions of the plurality of matrix junctions can comprise respective superconducting parallel branches that can comprise a plurality of Josephson junctions operatively coupled in a series configuration. A method can comprise forming a first matrix junction comprising arranging a first group of Josephson junctions as first parallel branches. The method can also comprise forming a second matrix junction comprising arranging a second group of Josephson junctions as second parallel branches. Further, the method can comprise forming a third matrix junction comprising arranging a third group of Josephson junctions as third parallel branches. In addition, the method can comprise forming a fourth matrix junction comprising arranging a fourth group of Josephson junctions as fourth parallel branches.

A capacitively-driven tunable coupler includes a coupling capacitor connecting an open end of a quantum object (i.e., an end of the object that cannot have a DC path to a low-voltage rail, such as a ground node, without breaking the functionality of the object) to an RF SQUID having a Josephson element capable of providing variable inductance and therefore variable coupling to another quantum object.

A quantum computing device is formed using a first chip and a second chip, the first chip having a first substrate, a first set of pads, and a set of Josephson junctions disposed on the first substrate. The second chip has a second substrate, a second set of pads disposed on the second substrate opposite the first set of pads, and a second layer formed on a subset of the second set of pads. The second layer is configured to bond the first chip and the second chip. The subset of the second set of pads corresponds to a subset of the set of Josephson junctions selected to avoid frequency collision between qubits in a set of qubits. A qubit is formed using a Josephson junction from the subset of Josephson junctions and another Josephson junction not in the subset being rendered unusable for forming qubits.

A flux-biasing device includes a set of magnetic flux generating members. A first magnetic flux generating member is configured to magnetically interact with a first qubit from a set of qubits of a quantum processor such that a first magnetic flux of the first member causes a first change in a first resonance frequency of the first qubit by a first frequency shift value. Each non-corresponding magnetic flux generating member of the set is well separated from qubits corresponding to other magnetic flux generating members of the set such that qubits corresponding to other members exhibit less than a threshold value of resonance frequency shift as a result of a magnetic flux of a non-corresponding member.

According to an embodiment of the present invention, a method for fabricating a Majorana fermion structure includes providing a substrate, and depositing a superconducting material on the substrate. The method includes depositing a magnetic material on the superconducting material using angled deposition through a mask. The method includes annealing the magnetic material and the superconducting material to form a magnetic nanowire partially embedded in the superconducting material such that the magnetic nanowire and the superconducting material form a Majorana fermion structure.

A transmon qubit comprising a plate capacitor comprising a first plate (202) and a second plate (203) wherein the first plate is disposed opposite to at least a part of the second plate, wherein the first plate and the second plate are connected via a nonlinear inductance element (304), and a capacitance (205) formed between the first plate and the second plate, wherein the first plate and the second plate are configured to form a vacuum gap capacitor.

Josephson junctions (JJ) based on bilayers of azimuthally misaligned two-dimensional materials having superconducting states are provided. Also provided are electronic devices and circuits incorporating the JJs as active components and methods of using the electronic devices and circuits. The JJs are formed from bilayers composed of azimuthally misaligned two-dimensional materials having a first superconducting segment and a second superconducting segment separated by a weak-link region that is integrated into the bilayer.

A superconducting complex quantum computing circuit includes a circuit substrate in which a wiring pattern of a circuit element including quantum bits and measurement electrodes, and ground patterns are formed, and through-electrodes connecting the ground pattern formed on a first surface of the substrate surface and the ground pattern formed on a second surface; a first ground electrode including a first contact portion in contact with the ground patterns, and a first non-contact portion having a shape corresponding to a shape of the wiring pattern; a second ground electrode including a second contact portion in contact with the ground pattern; a control signal line provided with a contact spring pin at a tip; and a pressing member that presses the first ground electrode against the first surface of the circuit substrate or presses the second ground electrode against the second surface of the circuit substrate.