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公开(公告)号：US11894860B2
公开(公告)日：2024-02-06
申请号：US17433459
申请日：2020-03-05
Applicant: Google LLC
Inventor： Jarrod Ryan McClean , Ryan Babbush , Zhang Jiang
CPC classification number: H03M13/1575 , G06N10/00
Abstract: Methods, systems and apparatus for correcting a result of a quantum computation. In one aspect, a method includes selecting a quantum error correcting code for the quantum computation, wherein the quantum error correcting code is defined by multiple stabilizer generators; determining a set of symmetry operators, comprising: selecting a subset of the stabilizer generators, determining, for each selected stabilizer generator, a sum between an identity operator and the stabilizer generator, and multiplying the determined sums together to form a summation of terms, wherein each term in the summation is equal to a respective symmetry operator; measuring a projective correction of a physical observable over an output quantum state of the quantum computation using the determined set of symmetry operators, wherein the physical observable corresponds to the result of the quantum computation; and determining a corrected result of the quantum computation using the measured projective correction of the physical observable.
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公开(公告)号：US12206412B2
公开(公告)日：2025-01-21
申请号：US18320532
申请日：2023-05-19
Applicant: Google LLC
IPC: H03K19/195 , G06N10/40
Abstract: The disclosure is directed to characterizing a quantum logic circuit (QLC), via a set of intrinsic parameters. One method includes selecting control vectors that are associated with phase shifts for the intrinsic parameters such that experimental unitary operators for the QLC are defined. Each experimental unitary operator is based on the intrinsic parameters and phase shifts associated with a corresponding control vector. For each control vector, eigenvalues for the corresponding unitary operator are estimated based on qubit measurements performed subsequent to tuning the QLC in accordance with the control vector. The eigenvalues correspond to quasienergy levels of the qubits. Values for the set of intrinsic parameters may be determined based on the eigenvalues.
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Patent Agency Ranking
公开(公告)号：US20240388297A1
公开(公告)日：2024-11-21
申请号：US18320532
申请日：2023-05-19
Applicant: Google LLC
IPC: H03K19/195 , G06N10/40
Abstract: The disclosure is directed to characterizing a quantum logic circuit (QLC), via a set of intrinsic parameters. One method includes selecting control vectors that are associated with phase shifts for the intrinsic parameters such that experimental unitary operators for the QLC are defined. Each experimental unitary operator is based on the intrinsic parameters and phase shifts associated with a corresponding control vector. For each control vector, eigenvalues for the corresponding unitary operator are estimated based on qubit measurements performed subsequent to tuning the QLC in accordance with the control vector. The eigenvalues correspond to quasienergy levels of the qubits. Values for the set of intrinsic parameters may be determined based on the eigenvalues.
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公开(公告)号：US20220029639A1
公开(公告)日：2022-01-27
申请号：US17433459
申请日：2020-03-05
Applicant: Google LLC
Inventor： Jarrod Ryan McClean , Ryan Babbush , Zhang Jiang
Abstract: Methods, systems and apparatus for correcting a result of a quantum computation. In one aspect, a method includes selecting a quantum error correcting code for the quantum computation, wherein the quantum error correcting code is defined by multiple stabilizer generators; determining a set of symmetry operators, comprising: selecting a subset of the stabilizer generators, determining, for each selected stabilizer generator, a sum between an identity operator and the stabilizer generator, and multiplying the determined sums together to form a summation of terms, wherein each term in the summation is equal to a respective symmetry operator; measuring a projective correction of a physical observable over an output quantum state of the quantum computation using the determined set of symmetry operators, wherein the physical observable corresponds to the result of the quantum computation; and determining a corrected result of the quantum computation using the measured projective correction of the physical observable.
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15.发明申请公开(公告)号：US20220019931A1
公开(公告)日：2022-01-20
申请号：US17428189
申请日：2020-02-14
Applicant: Google LLC
Inventor： Zhang Jiang , Ryan Babbush , Jarrod Ryan McClean , Nicholas Charles Rubin
Abstract: Methods, systems and apparatus for simulating physical systems. In one aspect, a method includes the actions of selecting a first set of basis functions for the simulation, wherein the first set of basis functions comprises an active and a virtual set of orbitals; defining a set of expansion operators for the simulation, wherein expansion operators in the set of expansion operators approximate fermionic excitations in an active space spanned by the active set of orbitals and a virtual space spanned by the virtual set of orbitals; performing multiple quantum computations to determine a matrix representation of a Hamiltonian characterizing the system in a second set of basis functions, computing, using the determined matrix representation of the Hamiltonian, eigenvalues and eigenvectors of the Hamiltonian; and determining properties of the physical system using the computed eigenvalues and eigenvectors.
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公开(公告)号：US20220019928A1
公开(公告)日：2022-01-20
申请号：US17296160
申请日：2019-12-17
Applicant: Google LLC
Inventor： Zhang Jiang , Ryan Babbush , Jarrod Ryan McClean
Abstract: Methods, systems and apparatus for error correction of fermionic quantum simulation. In one aspect, a method includes representing a fermionic system as a graph of vertices and edges, where each vertex represents a fermionic system fermionic mode and each edge represents an interaction between two respective fermionic modes; allocating a qubit to each edge in the graph to form a qubit system; determining qubit operators that satisfy a set of fermionic commutation and dependence relations, where the qubit operators are non-uniform with respect to the graph vertices; determining stabilizer operators corresponding to products of quadratic Majorana operators on respective loops in the graph, where a common eigenspace of the defined stabilizer operators defines a code subspace that encodes states of the fermionic system to be simulated; and simulating the fermionic system by evolving the qubit system under a qubit Hamiltonian that includes the determined qubit operators and stabilizer operators.
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公开(公告)号：US20210304054A1
公开(公告)日：2021-09-30
申请号：US17218690
申请日：2021-03-31
Applicant: Google LLC
Inventor： Charles James Neill , Vadim Smelyanskiy , Yu Chen , Xiao Mi , Yuezhen Niu , Kostyantyn Yevgenovych Kechedzhi , Alexander Nikolaevich Korotkov , Zhang Jiang
Abstract: Systems and methods for composite quantum gate calibration for a quantum computing system are provided. In some implementations, a method includes accessing a unitary gate model describing a composite quantum gate. The unitary gate model includes a plurality of gate parameters. The method includes implementing the composite quantum gate for a plurality of gate cycles on the quantum system to amplify the plurality of gate parameters. The method includes obtaining a measurement of a state of the quantum system after implementing the composite quantum gate for the plurality of gate cycles. The method includes determining at least one of the plurality of gate parameters based at least in part on the measurement of the state of the quantum system. The method includes calibrating the composite quantum gate for the quantum computing system based at least in part on the plurality of gate parameters.
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