Reducing parasitic interactions in a qubit grid

    公开(公告)号:US11694104B2

    公开(公告)日:2023-07-04

    申请号:US16636510

    申请日:2017-08-09

    Applicant: GOOGLE LLC

    CPC classification number: G06N10/00

    Abstract: Methods, systems, and apparatus for performing an entangling operation on a system of qubits. In one aspect, a method includes operating the system of qubits, wherein the system of qubits comprises: a plurality of first qubits, a plurality of second qubits, a plurality of qubit couplers defining nearest neighbor interactions between the first qubits and second qubits, wherein the system of qubits is arranged as a two dimensional grid and each qubit of the multiple first qubits is coupled to multiple second qubits through respective qubit couplers, and wherein operating the system of qubits comprises: pairing multiple first qubits with respective neighboring second qubits; performing an entangling operation on each paired first and second qubit in parallel, comprising detuning each second qubit in the paired first and second qubits in parallel.

    Frequency pattern for reducing parasitic interactions in a qubit grid

    公开(公告)号:US11687820B2

    公开(公告)日:2023-06-27

    申请号:US17350545

    申请日:2021-06-17

    Applicant: Google LLC

    CPC classification number: G06N10/00 G06F15/80

    Abstract: Methods, systems, and apparatus for operating a system of qubits. In one aspect, a method includes operating a first qubit from a first plurality of qubits at a first qubit frequency from a first qubit frequency region, and operating a second qubit from the first plurality of qubits at a second qubit frequency from a second first qubit frequency region, the second qubit frequency and the second first qubit frequency region being different to the first qubit frequency and the first qubit frequency region, respectively, wherein the second qubit is diagonal to the first qubit in a two-dimensional grid of qubits.

    FIDELITY ESTIMATION FOR QUANTUM COMPUTING SYSTEMS

    公开(公告)号:US20220138610A1

    公开(公告)日:2022-05-05

    申请号:US17574192

    申请日:2022-01-12

    Applicant: Google LLC

    Abstract: Methods and apparatus for estimating the fidelity of quantum hardware. In one aspect, a method includes accessing a set of quantum gates; sampling a subset of quantum gates from the set of quantum gates, wherein the subset of quantum gates defines a quantum circuit; applying the quantum circuit to a quantum system and performing measurements on the quantum system to determine output information of the quantum system; calculating output information of the quantum system based on application of the quantum circuit to the quantum system; and estimating a fidelity of the quantum circuit based on the determined output information and the calculated output information of the quantum system.

    Butt joint flex circuit board interconnection

    公开(公告)号:US11923628B2

    公开(公告)日:2024-03-05

    申请号:US17476755

    申请日:2021-09-16

    Applicant: Google LLC

    CPC classification number: H01R12/61 H01R43/02 H05K1/0281 H05K1/023 H05K1/09

    Abstract: Interconnections for connecting flex circuit boards in classical and/or quantum computing systems can include a first flex circuit board having a removed portion that exposes one or more signal lines and a second flex circuit board having a removed portion that exposes one or more other signal lines. The flex circuit boards can be aligned at the removed portions to form a signal trace gap near the exposed signal lines. Exposed signal lines of the first flex circuit board can be coupled with exposed signal lines of the second flex circuit board. A ground support layer can be coupled to the first flex circuit board and the second flex circuit board along the same side. An isolation plate at least partially covering the signal trace gap can be coupled to the first flex circuit board and/or the second flex circuit board on a side opposite of the ground support layer.

    Overlap Joint Flex Circuit Board Interconnection

    公开(公告)号:US20240049392A1

    公开(公告)日:2024-02-08

    申请号:US18355199

    申请日:2023-07-19

    Applicant: Google LLC

    Abstract: An interconnection for flex circuit boards used, for instance, in a quantum computing system are provided. In one example, the interconnection can include a first flex circuit board having a first side and a second side opposite the first side. The interconnection can include a second flex circuit board having a third side and a fourth side opposite the third side. The first flex circuit board and the second flex circuit board are physically coupled together in an overlap joint in which a portion of the second side for the first flex circuit board overlaps a portion of the third side of the flex circuit board. The interconnection can include a signal pad structure positioned in the overlap joint that electrically couples a first via in the first flex circuit board and a second via in the second flex circuit board.

    NONLINEAR CALIBRATION OF A QUANTUM COMPUTING APPARATUS

    公开(公告)号:US20230316117A1

    公开(公告)日:2023-10-05

    申请号:US18298576

    申请日:2023-04-11

    Applicant: Google LLC

    CPC classification number: G06N10/00 G06F18/214 G06F30/25

    Abstract: Methods, systems, and apparatus for nonlinear calibration of quantum computing apparatus. In one aspect, elements in a set of experimental data correspond to a respective configuration of control biases for the quantum computing apparatus. An initial physical model comprising one or more model parameters of the quantum computing apparatus is defined. The model is iteratively adjusted to determine a revised physical model, where at each iteration: a set of predictive data corresponding to the set of experimental data is generated, and elements in the predictive data represent a difference between the two smallest eigenvalues of a Hamiltonian characterizing the system qubits for the previous iteration, and are dependent on at least one model parameter of the physical model for the previous iteration; and the model for the previous iteration is adjusted using the obtained experimental data and the generated set of predictive data for the iteration.

    Overlap joint flex circuit board mating

    公开(公告)号:US11751333B2

    公开(公告)日:2023-09-05

    申请号:US17476625

    申请日:2021-09-16

    Applicant: Google LLC

    Abstract: An interconnection for flex circuit boards used, for instance, in a quantum computing system are provided. In one example, the interconnection can include a first flex circuit board having a first side and a second side opposite the first side. The interconnection can include a second flex circuit board having a third side and a fourth side opposite the third side. The first flex circuit board and the second flex circuit board are physically coupled together in an overlap joint in which a portion of the second side for the first flex circuit board overlaps a portion of the third side of the flex circuit board. The interconnection can include a signal pad structure positioned in the overlap joint that electrically couples a first via in the first flex circuit board and a second via in the second flex circuit board.

    Nonlinear calibration of a quantum computing apparatus

    公开(公告)号:US11651263B2

    公开(公告)日:2023-05-16

    申请号:US16624037

    申请日:2017-12-15

    Applicant: Google LLC

    CPC classification number: G06N10/00 G06F18/214 G06F30/25

    Abstract: Methods, systems, and apparatus for nonlinear calibration of quantum computing apparatus. In one aspect, elements in a set of experimental data correspond to a respective configuration of control biases for the quantum computing apparatus. An initial physical model comprising one or more model parameters of the quantum computing apparatus is defined. The model is iteratively adjusted to determine a revised physical model, where at each iteration: a set of predictive data corresponding to the set of experimental data is generated, and elements in the predictive data represent a difference between the two smallest eigenvalues of a Hamiltonian characterizing the system qubits for the previous iteration, and are dependent on at least one model parameter of the physical model for the previous iteration; and the model for the previous iteration is adjusted using the obtained experimental data and the generated set of predictive data for the iteration.

    Integrated readout card
    29.
    发明授权

    公开(公告)号:US11411159B1

    公开(公告)日:2022-08-09

    申请号:US17104826

    申请日:2020-11-25

    Applicant: Google LLC

    Abstract: An integrated qubit readout circuit is presented, which includes a superconducting parametric amplifier, a circuit board arranged to mount the superconducting parametric amplifier, a circulator mounted on the circuit board and connected to the superconducting parametric amplifier, wherein the circulator comprises a termination port electrically connected to a termination resistor arranged to terminate a pump tone received by the superconducting parametric amplifier, and wherein the termination resistor is mounted on the circuit board.

    Overlap Joint Flex Circuit Board Mating

    公开(公告)号:US20220087022A1

    公开(公告)日:2022-03-17

    申请号:US17476625

    申请日:2021-09-16

    Applicant: Google LLC

    Abstract: An interconnection for flex circuit boards used, for instance, in a quantum computing system are provided. In one example, the interconnection can include a first flex circuit board having a first side and a second side opposite the first side. The interconnection can include a second flex circuit board having a third side and a fourth side opposite the third side. The first flex circuit board and the second flex circuit board are physically coupled together in an overlap joint in which a portion of the second side for the first flex circuit board overlaps a portion of the third side of the flex circuit board. The interconnection can include a signal pad structure positioned in the overlap joint that electrically couples a first via in the first flex circuit board and a second via in the second flex circuit board.

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