Abstract: Techniques for designing and fabricating quantum circuitry, including a coplanar waveguide (CPW), for quantum applications are presented. With regard to a CPW, a central conductor and two return conductor lines can be formed on a dielectric substrate, with one return conductor line on each side of the central conductor and separated from it by a space. The central conductor can have bridge portions that can be raised a desired distance above the substrate and base conductor portions situated between the bridge portions and in contact with the surface of the substrate; and/or portions of the substrate underneath the bridge portions of the central conductor can be removed such that the bridge portions, whether raised or unraised, can be the desired distance above the surface of the remaining substrate, and the base conductor portions can be in contact with other portions of the surface of the substrate that were not removed.

Abstract: Techniques regarding determining the temperature of one or more quantum computing devices are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a temperature component that can determine a temperature of a superconducting resonator based on a frequency shift exhibited by the superconducting resonator due to a change in kinetic inductance with a change in temperature.

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: Techniques regarding determining and/or analyzing temperature distributions experienced by quantum computer devices during operation are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a memory that can store computer executable components. The system can also comprise a processor, operably coupled to the memory, and that can execute the computer executable components stored in the memory. The computer executable components can comprise a region component that can define a plurality of temperature regions from a quantum computing device layout. The computer executable component can also comprise a map component that can generate a map that characterizes a temperature distribution by determining at least one temperature achieved within the plurality of temperature regions during an operation of the quantum computing device layout.

Abstract: A monolithic silicon Josephson junction can be fabricated from a silicon wafer using semiconductor technologies such as gas immersion laser doping and smart cut technology. Rather than using a superconducting metal for the junction electrodes, silicon that has been highly doped with boron can serve as the superconducting material for the electrodes of the Josephson junction. A region of the silicon wafer that has not been doped serves as the tunnel barrier. Fabrication of the Josephson junction does not require a metallization process since the electrodes and tunnel barrier are formed from highly doped silicon and non-doped silicon, respectively. The single-crystal structure of the resulting Josephson junction yields low two-level system (TLS) noise.

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 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: 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: Systems and techniques that facilitate quantum-enhanced features for classical machine learning are provided. In various embodiments, a system can comprise a receiver component that can access a classical dataset. In various aspects, the system can further comprise a feature component that can generate one or more machine learning input features based on a quantum transformation of the classical data set. In various instances, the system can further comprise an execution component that can execute a classical machine learning model on the one or more machine learning input features.

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.

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.

Abstract: A quantum computing system includes a dilution refrigerator having a plurality of chambers. A trapped ion computing device includes a first set of qubits in a given chamber of the plurality of chambers of the dilution refrigerator. A superconducting computing device having a second set of superconducting qubits is inside the given chamber of the plurality of chambers of the dilution refrigerator.

Abstract: Systems and techniques that facilitate hybrid readout packaging for quantum multichip bonding are provided. In various embodiments, an interposer can have a first quantum chip and a second quantum chip. In various aspects, a readout resonator (e.g., input/output port) of one or more qubits on the first quantum chip can be routed to an inner portion of the interposer. In various instances, the inner portion can be located between the first quantum chip and the second quantum chip. In various aspects, routing the readout resonator to the inner portion can reduce a number of crossings and/or intersections between input/output lines on the interposer and connection buses between qubits on the interposer.

Abstract: In an embodiment, a quantum device includes a first set of protrusions formed on a substrate and a second set of protrusions formed on a qubit chip. In the embodiment, the quantum device includes a set of bumps formed on an interposer, the set of bumps formed of a material having above a threshold ductility at a room temperature range, wherein a first subset of the set of bumps is configured to cold weld to the first set of protrusions and a second subset of the set of bumps is configured to cold weld to the second set of protrusions.

Abstract: Techniques for designing and fabricating quantum circuitry, including a coplanar waveguide (CPW), for quantum applications are presented. With regard to a CPW, a central conductor and two return conductor lines can be formed on a dielectric substrate, with one return conductor line on each side of the central conductor and separated from it by a space. The central conductor can have bridge portions that can be raised a desired distance above the substrate and base conductor portions situated between the bridge portions and in contact with the surface of the substrate; and/or portions of the substrate underneath the bridge portions of the central conductor can be removed such that the bridge portions, whether raised or unraised, can be the desired distance above the surface of the remaining substrate, and the base conductor portions can be in contact with other portions of the surface of the substrate that were not removed.

Abstract: Systems and techniques that facilitate hybrid readout packaging for quantum multichip bonding are provided. In various embodiments, an interposer can have a first quantum chip and a second quantum chip. In various aspects, a readout resonator (e.g., input/output port) of one or more qubits on the first quantum chip can be routed to an inner portion of the interposer. In various instances, the inner portion can be located between the first quantum chip and the second quantum chip. In various aspects, routing the readout resonator to the inner portion can reduce a number of crossings and/or intersections between input/output lines on the interposer and connection buses between qubits on the interposer.

Abstract: A transition between a printed circuit board and a dielectric layer with controlled impedance and reduced and/or mitigate crosstalk for quantum applications are provided. A quantum device can comprise a microwave quantum circuit on a dielectric substrate and a printed circuit board comprising a via that comprises a transmission line. A wirebond between the transmission line of the printed circuit board and a transmission line of the microwave quantum circuit operatively couples the microwave quantum circuit to the printed circuit board. The via comprises a defined characteristic impedance. The wirebond provides a microwave signal connection between the printed circuit board and the microwave quantum circuit.

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: 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.