公开(公告)号：US20240354626A1

公开(公告)日：2024-10-24

申请号：US18156063

申请日：2023-01-18

Applicant: Google LLC

Inventor： Paul Victor Klimov ,  Trond Ikdahl Andersen ,  Yuezhen Niu ,  Vadim Smelyanskiy

IPC: G06N10/60 ,  G06N10/40

CPC classification number: G06N10/60 ,  G06N10/40

Abstract: Systems and methods for operating a quantum computing system are provided. In some examples, a method may include obtaining characterization data associated with an operating parameter of a qubit in a quantum computing system. The method may include implementing an unsupervised learning operation to extract one or more anomalies from the characterization data. The method may include operating the qubit in the quantum computing system based at least in part on the one or more anomalies.

公开(公告)号：US20240177038A1

公开(公告)日：2024-05-30

申请号：US18319947

申请日：2023-05-18

Applicant: Google LLC

Inventor： Yuezhen Niu ,  Vadim Smelyanskiy ,  Yulong Dong

IPC: G06N10/20 ,  G06N10/40

CPC classification number: G06N10/20 ,  G06N10/40

Abstract: Methods for calibrating a quantum circuit including a tunable quantum gate and a composite quantum gate characterized by a set of gate parameters are disclosed. For each modulation angle of a set of modulation angles, the quantum circuit is operated on a qubit pair for a plurality of gate cycles by tuning the tunable quantum gate. Gate characterization data is generated based on measurements of the qubit pair. A first representation of a state-transition probability vector is determined for the qubit pair based on the gate characterization data. Values for the gate parameters are transformed into orthogonal bases of parameters and are determined independently from each other based on the set of coefficients and statistical estimators. The method significantly boosts the accuracy of gate parameter learning by providing such separation between parameters and thus reduces unwanted error from one gate parameter to the other.

公开(公告)号：US20230274172A1

公开(公告)日：2023-08-31

申请号：US18311746

申请日：2023-05-03

Applicant: Google LLC

Inventor： Yuezhen Niu ,  Hartmut Niu ,  Vadim Smelyanskiy ,  Sergio Boixo Castrillo

IPC: G06N10/00 ,  H03K3/38

CPC classification number: G06N10/00 ,  H03K3/38

Abstract: Methods, systems, and apparatus for implementing a unitary quantum gate on one or more qubits. In one aspect, a method includes the actions designing a control pulse for the unitary quantum gate, comprising: defining a universal quantum control cost function, wherein the control cost function comprises a qubit leakage penalty term representing i) coherent qubit leakage, and ii) incoherent qubit leakage across all frequency components during a time dependent Hamiltonian evolution that realizes the unitary quantum gate; adjusting parameters of the time dependent Hamiltonian evolution to vary a control cost according to the control cost function such that leakage errors are reduced; generating the control pulse using the adjusted parameters; and applying the control pulse to the one or more qubits to implement the unitary quantum gate.

公开(公告)号：US20220414519A1

公开(公告)日：2022-12-29

申请号：US17777708

申请日：2020-11-16

Applicant: Google LLC

Inventor： Jarrod Ryan McClean ,  Sergio Boixo Castrillo ,  Craig Gidney ,  Vadim Smelyanskiy

IPC: G06N10/70 ,  G06N10/20

Abstract: Systems and methods for quantum error mitigation are provided. A method can include accessing a quantum system; implementing a plurality of quantum circuits; obtaining a plurality of measurements performed for each of the quantum circuits; determining an estimated average value of an observable of interest (O)f for the quantum circuits based at least in part on the plurality of measurements; and determining an estimated noiseless value of an observable of interest (O)ψ based at least in part on the estimated average value of the observable of interest (O)f using a single-point full depolarizing error model. Each of the plurality of quantum circuits can be implemented by a different sequence of quantum gates as compared to each of the other quantum circuits in the plurality to thereby implement one or more circuit gauges and can be an equivalent logical operation as each of the other quantum circuits in the plurality.

公开(公告)号：US20220414514A1

公开(公告)日：2022-12-29

申请号：US17694820

申请日：2022-03-15

Applicant: Google LLC

Inventor： Alexander Nikolaevich Korotkov ,  Kevin Joseph Satzinger ,  Matthew James McEwen ,  Vadim Smelyanskiy ,  Paul Victor Klimov ,  Rami Barends ,  Julian Shaw Kelly ,  Juan Carlos Atalaya-Chavez ,  Zijun Chen

IPC: G06N10/40

Abstract: A quantum computing system configured for removal of leakage states can include quantum hardware including a first qubit and a second qubit, wherein the first qubit is configured to have a first transition frequency and wherein the second qubit is configured to have a second transition frequency, the first transition frequency being greater than the second transition frequency. The quantum computing system can include one or more quantum control devices configured to control operation of at least the first qubit and the second qubit, wherein the one or more quantum control devices are configured to implement a quantum gate operation on the first qubit and the second qubit based at least in part on the first transition frequency and the second transition frequency, and wherein the one or more quantum control devices are configured to periodically reset a quantum state of the first qubit.

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

Inventor： John Martinis ,  Nan Ding ,  Ryan Babbush ,  Sergei V. Isakov ,  Hartmut Neven ,  Vadim Smelyanskiy ,  Sergio Boixo Castrillo

IPC: G06N10/00

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.