Abstract: A gated Josephson junction includes a substrate and a vertical Josephson junction formed on the substrate and extending substantially normal the substrate. The vertical Josephson junction includes a first superconducting layer, a semiconducting layer, and a second superconducting layer. The first superconducting layer, the semiconducting layer, and the second superconducting layer form a stack that is substantially perpendicular to the substrate. The gated Josephson junction includes a gate dielectric layer in contact with the first superconducting layer, the semiconducting layer, and the second superconducting layer at opposing side surfaces of the vertical Josephson junction, and a gate electrically conducting layer in contact with the gate dielectric layer. The gate electrically conducting layer is separated from the vertical Josephson junction by the gate dielectric layer.

Abstract: Protecting qubits of a quantum processor from spontaneous emission and thermal photon noise includes connecting a first port of a filter to a signal line of a readout resonator of a qubit circuit of a quantum processor. The filter has a passband including a readout resonator frequency associated with the readout resonator and a first stopband including a qubit transition frequency associated with the qubit circuit. A second port of the filter is connected to a measurement device. a signal line of the filter is galvanically connected to a reference ground in thermal contact to a stage of a cryostat. The galvanic connection further makes a thermal connection to an input signal line of the qubit circuit.

Abstract: A stripline that is usable in a quantum application (q-stripline) includes a first polyimide film and a second polyimide film. The q-stripline further includes a first center conductor and a second center conductor formed between the first polyimide film and the second polyimide film. The q-stripline has a first pin configured through the second polyimide film to make electrical and thermal contact with the first center conductor.

Abstract: A microstrip that is usable in a quantum application (q-microstrip) includes a ground plane, a polyimide film disposed over the ground plane at a first surface of the polyimide film, and a conductor formed on a second side of the polyimide film such that the first surface is substantially opposite to the second surface. A material of the conductor provides greater than a threshold thermal conductivity (TH) with a structure of a dilution fridge stage (stage).

Abstract: A superconducting coupling device includes a resonator structure. The resonator structure has a first end configured to be coupled to a first device and a second end configured to be coupled to a second device. The device further includes an electron system coupled to the resonator structure, and a gate positioned proximal to a portion of the electron system. The electron system and the gate are configured to interrupt the resonator structure at one or more predetermined locations forming a switch. The gate is configured to receive a gate voltage and vary an inductance of the electron system based upon the gate voltage. The varying of the inductance induces the resonator structure to vary a strength of coupling between the first device and the second device.

Abstract: Devices and methods that can facilitate vertical dispersive readout of qubits of a lattice surface code architecture are provided. According to an embodiment, a device can comprise a first substrate that can have a first side and a second side that can be opposite the first side. The first substrate can comprise a read pad that can be located on the first side and a readout resonator that can be located on the second side. The device can further comprise a second substrate that can be connected to the first substrate. The second substrate can comprise a qubit. In some embodiments, the device can further comprise a recess that can be located on the first side of the first substrate. The recess can comprise the read pad.

Abstract: A system for transmission of quantum information for quantum error correction includes an ancilla qubit chip including a plurality of ancilla qubits, and a data qubit chip spaced apart from the ancilla qubit chip, the data qubit chip including a plurality of data qubits. The system includes an interposer coupled to the ancilla qubit chip and the data qubit chip, the interposer including a dielectric material and a plurality of superconducting structures formed in the dielectric material. The superconducting structures enable transmission of quantum information between the plurality of data qubits on the data qubit chip and the plurality of ancilla qubits on the ancilla qubit chip via virtual photons for quantum error correction.

Abstract: A quantum computer includes a quantum computing system; a transducer disposed inside the quantum computing system, the transducer being configured to receive an optical control propagating wave and output a microwave control propagating wave; and a quantum processor comprising a plurality of qubits, the plurality of qubits being disposed in the quantum computing system, each qubit of the plurality of qubits being configured to receive at least a portion of the microwave control propagating wave to control a quantum state of each qubit of the plurality of qubits.

Abstract: A gated Josephson junction includes a substrate and a vertical Josephson junction formed on the substrate and extending substantially normal the substrate. The vertical Josephson junction includes a first superconducting layer, a semiconducting layer, and a second superconducting layer. The first superconducting layer, the semiconducting layer, and the second superconducting layer form a stack that is substantially perpendicular to the substrate. The gated Josephson junction includes a gate dielectric layer in contact with the first superconducting layer, the semiconducting layer, and the second superconducting layer at opposing side surfaces of the vertical Josephson junction, and a gate electrically conducting layer in contact with the gate dielectric layer. The gate electrically conducting layer is separated from the vertical Josephson junction by the gate dielectric layer.

Abstract: Techniques for facilitating reduced thermal resistance attenuator on high-thermal conductivity substrates for quantum applications are provided. A device can comprise a substrate that provides a thermal conductivity level that is more than a defined thermal conductivity level. The device can also comprise one or more grooved transmission lines formed in the substrate. The one or more grooved transmission lines can comprise a powder substance. Further, the device can comprise one or more copper heat sinks formed in the substrate. The one or more copper heat sinks can provide a ground connection. Further, the one or more copper heat sinks can be formed adjacent to the one or more grooved transmission lines.

Abstract: A quantum mechanical circuit includes a substrate; a first electrical conductor and a second electrical conductor provided on the substrate and spaced apart to provide a gap therebetween; and a third electrical conductor to electrically connect the first electrical conductor and the second electrical conductor. The third electrical conductor is a poor thermal conductor.

Abstract: A quantum computer includes a refrigeration system under vacuum including a containment vessel, a qubit chip contained within a refrigerated vacuum environment defined by the containment vessel. The quantum computer further includes a plurality of interior electromagnetic waveguides and a plurality of exterior electromagnetic waveguides. The quantum computer further includes a hermetic connector assembly operatively connecting the interior electromagnetic waveguides to the exterior electromagnetic waveguides while maintaining the refrigerated vacuum environment. The hermetic connector assembly includes an exterior multi-waveguide connector, an interior multi-waveguide connector, and a dielectric plate arranged between and hermetically sealed with the exterior multi-waveguide connector and the interior multi-waveguide connector. The dielectric plate permits electromagnetic energy when carried by the interior and exterior pluralities of electromagnetic waveguides to pass therethrough.

Abstract: An architecture for, and techniques for fabricating, a thermal decoupling device are provided. In some embodiments, thermal decoupling device can be included in a thermally decoupled cryogenic microwave filter. In some embodiments, the thermal decoupling device can comprise a dielectric material and a conductive line. The dielectric material can comprise a first channel that is separated from a second channel by a wall of the dielectric material. The conductive line can comprise a first segment and a second segment that are separated by the wall. The wall can facilitate propagation of a microwave signal between the first segment and the second segment and can reduce heat flow between the first segment and the second segment of the conductive line.

Abstract: Systems, computer-implemented methods, and computer program products that can facilitate determining a state of a qubit are described. According to an embodiment, a system can comprise a memory that stores computer executable components and a processor that executes the computer executable components stored in the memory. The computer executable components can comprise a relation determining component that can determine relation of a status signal of a quantum computing device to a noise value of the quantum computing device. The system can further include an operation time estimator that can estimate an operation time for the quantum computing device based on the relation of the status signal to the noise value.

Abstract: A system for transmission of quantum information for quantum error correction includes an ancilla qubit chip including a plurality of ancilla qubits, and a data qubit chip spaced apart from the ancilla qubit chip, the data qubit chip including a plurality of data qubits. The system includes an interposer coupled to the ancilla qubit chip and the data qubit chip, the interposer including a dielectric material and a plurality of superconducting structures formed in the dielectric material. The superconducting structures enable transmission of quantum information between the plurality of data qubits on the data qubit chip and the plurality of ancilla qubits on the ancilla qubit chip via virtual photons for quantum error correction.

Abstract: A quantum computing device is fabricated by forming, on a superconductor layer, a first resist pattern defining a device region and a sensing region within the device region. The superconductor layer within the sensing region is removed, exposing a region of an underlying semiconductor layer outside the device region. The exposed region of the semiconductor layer is implanted, forming an isolation region surrounding the device region. Using an etching process subsequent to the implanting, the sensing region and a portion of the device region of the superconductor layer adjacent to the isolation region are exposed. By depositing a first metal layer within the sensing region, a tunnel junction gate is formed. A reflectrometry wire comprising a second metal within the reflectrometry region is formed. A nanorod contact using the second metal within the portion of the device region outside the sensing region is formed.

Abstract: A quantum system includes a qubit array comprising a plurality of qubits. A bus resonator is coupled between at least one pair of qubits in the qubit array. A switch is coupled between the at least one qubit pair of qubits.

Abstract: Techniques for facilitating reduced thermal resistance attenuator on high-thermal conductivity substrates for quantum applications are provided. A device can comprise a substrate that provides a thermal conductivity level that is more than a defined thermal conductivity level. The device can also comprise one or more grooved transmission lines formed in the substrate. The one or more grooved transmission lines can comprise a powder substance. Further, the device can comprise one or more copper heat sinks formed in the substrate. The one or more copper heat sinks can provide a ground connection. Further, the one or more copper heat sinks can be formed adjacent to the one or more grooved transmission lines.

Abstract: Devices, systems, methods, and computer-implemented methods to facilitate employing thermalizing materials in an enclosure for quantum computing devices are provided. According to an embodiment, a system can comprise a quantum computing device and an enclosure having the quantum computing device disposed within the enclosure. The system can further comprise a thermalizing material disposed within the enclosure, with the thermalizing material being adapted to thermally link a cryogenic device to the quantum computing device.

Abstract: 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.