Technology is disclosed herein that the enhances the measurability and scalability of qubits in a quantum computing environment. In an implementation, a superconducting amplifier device comprises a parametric amplifier and a tunable coupling between the parametric amplifier and a readout cavity external to the superconducting amplifier device. The tunable coupling allows an entangled signal, associated with a qubit in the readout cavity, to transfer from the readout cavity to the parametric amplifier. The parametric amplifier amplifies the entangled signal to produce an amplified signal as output to a measurement sub-system.

A superconducting device that mixes surface acoustic waves and microwave signals and techniques for fabricating the same are provided. A superconducting device can comprise a superconducting surface acoustic wave resonator and a superconducting microwave resonator. The superconducting device can also comprise a Josephson ring modulator coupled to the superconducting surface acoustic wave resonator and the superconducting microwave resonator. The Josephson ring modulator can be a dispersive nonlinear three-wave mixing element.

A superconducting device that mixes surface acoustic waves and microwave signals and techniques for fabricating the same are provided. A superconducting device can comprise a superconducting surface acoustic wave resonator and a superconducting microwave resonator. The superconducting device can also comprise a Josephson ring modulator coupled to the superconducting surface acoustic wave resonator and the superconducting microwave resonator. The Josephson ring modulator can be a dispersive nonlinear three-wave mixing element.

A system includes a quantum processor includes a plurality of qubits. For each qubit, there is a circulator operative to receive a control signal and an output signal from the qubit. An isolator is coupled to an output of the circulator. A quantum-limited amplifier is coupled to an output of the isolator and configured to provide an output of the qubit. A multiplexor (MUX) is configured to frequency multiplex the outputs of at least two of the plurality of qubits as a single output of the quantum processor.

A circuit device includes a semiconductor device and an impedance matching network. The impedance matching network includes a superconductor material forming at least one inductor of the circuit device, and the superconductor material exhibits a kinetic inductance per unit square when in a superconducting state. The impedance matching network is configured to transform an impedance of the semiconductor device to match a predetermined second impedance during operation of the circuit device.

A circuit device includes a semiconductor device and an impedance matching network. The impedance matching network includes a superconductor material forming at least one inductor of the circuit device, and the superconductor material exhibits a kinetic inductance per unit square when in a superconducting state. The impedance matching network is configured to transform an impedance of the semiconductor device to match a predetermined second impedance during operation of the circuit device.

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.

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.

An aspect includes one or more board layers. A first chip cavity is formed within the one or more board layers, wherein a first Josephson amplifier or Josephson mixer is disposed within the first chip cavity. The first Josephson amplifier or Josephson mixer comprises at least one port, each port connected to at least one connector disposed on at least one of the one or more board layers, wherein at least one of the one or more board layers comprises a circuit trace formed on the at least one of the one or more board layers.