Abstract: Techniques facilitating efficient thermal profile management within cryogenic environments are provided. In one example, a cryostat can comprise a plurality of thermal stages intervening between a 4-Kelvin (K) stage and a Cold Plate stage. The plurality of thermal stages can include a Still stage and an intermediate thermal stage that provides additional cooling capacity for the cryostat. The intermediate thermal stage can be directly coupled mechanically to the Still stage via a support rod.

Abstract: Techniques facilitating mechanical vibration management for cryogenic environments are provided. In one example, a system can comprise a processor that executes computer executable components stored in memory. The computer executable components can comprise a linearization component and a drive component. The linearization component can translate data indicative of a nonlinear drive signal into a linear drive signal. The drive component can dynamically control operation of a compressor of a cryocooler using the linear drive signal. The cryocooler can provide cooling capacity for a cryogenic environment.

Abstract: Techniques facilitating transfer port systems for cryogenic environments are provided. In one example, an outer vacuum chamber of a cryostat can comprise a sidewall encompassing an inner chamber comprising a sample mounting surface. The sidewall can comprise a feedthrough port providing access to the sample mounting surface from a region external to the outer vacuum chamber.

Abstract: Techniques facilitating multiple cryogenic systems sectioned within a common vacuum space are provided. In one example, a cryostat can comprise a plurality of thermal stages and a thermal switch. The plurality of thermal stages can intervene between a 4-Kelvin (K) stage and a Cold Plate stage. The plurality of thermal stages can include a Still stage and an intermediate thermal stage that can be directly coupled mechanically to the Still stage via a support rod. The thermal switch can be coupled to the intermediate thermal stage and an adjacent thermal stage. The thermal switch can facilitate modifying a thermal profile of the cryostat by providing a switchable thermal path between the intermediate thermal stage and the adjacent thermal stage.

Abstract: Techniques facilitating custom thermal shields for cryogenic environments are provided. In one example, a cryostat can comprise a thermal shield extending between a thermal stage and a base structure coupled to a bottom plate of an outer vacuum chamber. The thermal stage can be coupled to a top plate of the outer vacuum chamber. The thermal shield can provide access to a sample mounting surface encompassed within the thermal shield from a region external to the outer vacuum chamber via the top and bottom plates of the outer vacuum chamber.

Abstract: A device includes a first substrate formed of a first material that exhibits a threshold level of thermal conductivity. The threshold level of thermal conductivity is achieved at a cryogenic temperature range in which a quantum circuit operates. In an embodiment, the device also includes a second substrate disposed in a recess of the first substrate, the second substrate formed of a second material that exhibits a second threshold level of thermal conductivity. The second threshold level of thermal conductivity is achieved at a cryogenic temperature range in which a quantum circuit operates. In an embodiment, at least one qubit is disposed on the second substrate. In an embodiment, the device also includes a transmission line configured to carry a microwave signal between the first substrate and the second substrate.

Abstract: The technology described herein is directed towards a cryogenic-stripline microwave attenuator. A first high thermal conductivity substrate such as sapphire and a second high thermal conductivity substrate such as sapphire, along with a signal conductor comprising one or more attenuator lines between the substrates form a stripline. A compression component such as one or more screws, vias (plus clamps) and/or clamps presses the first high thermal conductivity substrate against one side of the signal conductor and presses the second high thermal conductivity substrate against another side of the signal conductor. The high thermal conductivity of the substrates facilitates improved thermalization, while the pressing of the substrates against the conductor reduces the thermal boundary (Kapitza) resistance and thereby, for example, improves thermalization and reduces thermal noise.

Abstract: A qubit includes a substrate, and a first capacitor structure having a lower portion formed on a surface of the substrate and at least one first raised portion extending above the surface of the substrate. The qubit further includes a second capacitor structure having a lower portion formed on the surface of the substrate and at least one second raised portion extending above the surface of the substrate. The first capacitor structure and the second capacitor structure are formed of a superconducting material. The qubit further includes a junction between the first capacitor structure and the second capacitor structure. The junction is disposed at a predetermined distance from the surface of the substrate and has a first end in contact with the first raised portion and a second end in contact with the second raised portion.

Abstract: Lattice arrangements for quantum qubits are described. A lattice arrangement can comprise adjacent structures having vertices connected by edges. The qubits can be positioned on the vertices. A qubit in the lattice arrangement directly connects to not more than three other qubits, or connects to another qubit via a coupling qubit on an edge between two qubits on a vertex. The adjacent structures can comprise hexagons, dodecagons or octagons. A superconducting qubit lattice can comprise superconducting target qubits and superconducting control qubits. The superconducting qubit lattice can comprise adjacent structures having vertices connected by edges, with target qubits positioned on the vertices and control qubits positioned on the edges. Logic operations between adjacent superconducting target and control qubits can be implemented by driving the superconducting control qubit at or near the frequency of the superconducting target qubit.

Abstract: Devices and/or computer-implemented methods to facilitate a cross-resonance operation in a dispersive regime of a qubit frequency space are provided. According to an embodiment, a device can comprise a first qubit having a first operating frequency and a first anharmonicity. The device can further comprise a second qubit that couples to the first qubit to perform a cross-resonance operation. The second qubit having a second operating frequency and a second anharmonicity. A detuning between the first operating frequency and the second operating frequency is larger than the first anharmonicity and the second anharmonicity.

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 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.

Abstract: In an embodiment, a quantum device includes an interposer layer comprising a set of vias. In an embodiment, the quantum device includes a dielectric layer formed on a first side of the interposer, the dielectric layer including a set of transmission lines communicatively coupled to the set of vias. In an embodiment, the quantum device includes a plurality of qubit chips coupled to an opposite side of the interposer layer, each qubit chip of the plurality of qubit chips including: a plurality of qubits on a first side of the qubit chip and a plurality of protrusions on a second side of the qubit chip. In an embodiment, the quantum device includes a heat sink thermally coupled with the plurality of qubit chips, the heat sink comprising a plurality of recesses aligned with the plurality of protrusions of the plurality of qubit chips.

Abstract: Devices, systems, methods, computer-implemented methods, apparatus, and/or computer program products that can facilitate a switch device that shifts frequency of a resonator in a quantum device are provided. According to an embodiment, a device can comprise a readout resonator coupled to a qubit. The device can further comprise a switch device formed across the readout resonator that shifts frequency of the readout resonator based on position of the switch device. According to another embodiment, a device can comprise a bus resonator coupled to a plurality of qubits. The device can further comprise a switch device formed across the bus resonator that shifts frequency of the bus resonator based on position of the switch device.

Abstract: In a system including a cross-resonance gate having a superconducting control qubit and having a superconducting target qubit coupled through a bus resonator, echo pulses are generated at a first frequency and directed to the control qubit, wherein the first frequency is on resonance with the control qubit. Cross-resonance pulses are generated at a second frequency on resonance with the target qubit and applied to the control qubit, wherein the generating and applying the cross-resonance pulses induce rotations on the target qubit through an interaction that is mediated by the bus resonator. Cancellation pulses are generated at the second frequency and applied to the target qubit. Sets of Hamiltonian tomographies may be measured to determine appropriate amplitudes and phases of the cross-resonance and cancellation pulses.

Abstract: Lattice arrangements for quantum qubits are described. A lattice arrangement can comprise adjacent structures having vertices connected by edges. The qubits can be positioned on the vertices. A qubit in the lattice arrangement directly connects to not more than three other qubits, or connects to another qubit via a coupling qubit on an edge between two qubits on a vertex. The adjacent structures can comprise hexagons, dodecagons or octagons. A superconducting qubit lattice can comprise superconducting target qubits and superconducting control qubits. The superconducting qubit lattice can comprise adjacent structures having vertices connected by edges, with target qubits positioned on the vertices and control qubits positioned on the edges. Logic operations between adjacent superconducting target and control qubits can be implemented by driving the superconducting control qubit at or near the frequency of the superconducting target qubit.

Abstract: A method for adjusting a resonance frequency of a qubit in a quantum mechanical device includes providing a substrate having a frontside and a backside, the frontside having at least one qubit formed thereon, the at least one qubit comprising capacitor pads; and removing substrate material from the backside of the substrate at an area opposite the at least one qubit to alter a capacitance around the at least one qubit so as to adjust a resonance frequency of the at least one qubit.

Abstract: Devices, systems, methods, computer-implemented methods, apparatus, and/or computer program products that can facilitate a switch device that shifts frequency of a resonator in a quantum device are provided. According to an embodiment, a device can comprise a readout resonator coupled to a qubit. The device can further comprise a switch device formed across the readout resonator that shifts frequency of the readout resonator based on position of the switch device. According to another embodiment, a device can comprise a bus resonator coupled to a plurality of qubits. The device can further comprise a switch device formed across the bus resonator that shifts frequency of the bus resonator based on position of the switch device.

Abstract: According to an embodiment of the present invention, a system for non-invasively characterizing a qubit device includes a characterization probe chip. The characterization probe chip includes a substrate and a characterization resonator formed on a first surface of the substrate. The characterization resonator includes a superconducting stripline, and a superconducting antenna coupled to an end of the superconducting stripline, the superconducting antenna positioned to align with a qubit on the qubit device being characterized. The characterization probe chip also includes and a superconducting ground plane formed on a second surface of the substrate, the second surface opposing the first surface. In operation, the superconducting antenna is configured to capacitively couple the characterization resonator to the qubit aligned with the superconducting antenna for characterization of the qubit.

Abstract: According to an embodiment of the present invention, a system for non-invasively characterizing a qubit device includes a characterization probe chip. The characterization probe chip includes a substrate and a characterization resonator formed on a first surface of the substrate. The characterization resonator includes a superconducting stripline, and a superconducting antenna coupled to an end of the superconducting stripline, the superconducting antenna positioned to align with a qubit on the qubit device being characterized. The characterization probe chip also includes and a superconducting ground plane formed on a second surface of the substrate, the second surface opposing the first surface. In operation, the superconducting antenna is configured to capacitively couple the characterization resonator to the qubit aligned with the superconducting antenna for characterization of the qubit.