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公开(公告)号：US20240346360A1
公开(公告)日：2024-10-17
申请号：US18510020
申请日：2023-11-15
Applicant: Google LLC
Inventor： Ryan Babbush , Joonho Lee , William Huggins
IPC: G06N10/80
CPC classification number: G06N10/80
Abstract: Methods, systems, and apparatus for simulating a quantum system. In one aspect, a method includes performing a first quantized quantum algorithm on an initial quantum state to simulate time evolution of a fermionic system and generate a time evolved quantum state; and measuring, by the quantum computer, the time evolved quantum state to obtain one or more reduced density matrices in first quantization, the measuring including performing a classical shadows method that applies separate random Clifford channels to each qubit register of multiple qubit registers that represent respective occupied orbitals in the fermionic system.
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2.发明公开公开(公告)号：US20240296362A1
公开(公告)日：2024-09-05
申请号：US18574922
申请日：2022-06-28
Applicant: Google LLC
Inventor： William Huggins , Joonho Lee , Ryan Babbush
IPC: G06N10/20
CPC classification number: G06N10/20
Abstract: Methods, systems, and apparatus for hybrid quantum-classical quantum Monte Carlo. In one aspect, a method includes receiving, by a classical computer, data generated by a quantum computer, the data representing results of measurements of a trial wavefunction, wherein the trial wavefunction approximates the target wavefunction and is prepared by the quantum computer, computing, by the classical computer, a classical shadow of the trial wavefunction using the data representing the results of the measurements of the trial wavefunction, and performing, by the classical computer, imaginary time propagation for a sequence of imaginary time steps of an initial wavefunction using a Hamiltonian that characterizes the fermionic quantum system, wherein: the imaginary time propagation is performed until predetermined convergence criteria are met; and performing each imaginary time step of the imaginary time propagation comprises updating the wavefunction for the previous imaginary time step using the classical shadow of the trial wavefunction to obtain a wavefunction for the current imaginary time step.
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Patent Agency Ranking
公开(公告)号：US20230385674A1
公开(公告)日：2023-11-30
申请号：US18202828
申请日：2023-05-26
Applicant: Google LLC
Inventor： Kianna Wan , William Huggins
Abstract: Methods, systems, and apparatus for enhancing classical shadows using matchgate quantum circuits. In one aspect, a method for computing a classical shadow of an n-qubit quantum state includes repeatedly sampling, by a classical computer, a unitary operator from an ensemble of random unitaries, wherein the ensemble of random unitaries comprises a generalized matchgate group; for each sampled unitary operator: applying, by a quantum computer, a quantum circuit to the n-qubit quantum state to obtain an evolved quantum state, wherein the quantum circuit implements the sampled unitary operator, measuring, by the quantum computer, the evolved quantum state to obtain a respective bit string, and storing, by the classical computer, a record of the respective bit string and the sampled unitary operator; and providing the records as a classical shadow of the quantum state.
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公开(公告)号：US12282827B2
公开(公告)日：2025-04-22
申请号：US18036252
申请日：2021-11-11
Applicant: Google LLC
Inventor： William Huggins , Jarrod Ryan McClean
Abstract: Methods, systems and apparatus for determining an error-mitigated expectation value of a target observable with respect to a noisy quantum state. In one aspect a method includes obtaining multiple copies of the noisy quantum state; performing measurements on tensor products of M copies of the noisy quantum state to compute an expectation value of the target observable with respect to an entangled quantum state, wherein M?1 and eigenvalues corresponding to non-dominant eigenvectors of the noisy quantum state in the spectral decomposition of the entangled quantum state are suppressed exponentially in M; and using the computed expectation value of the target observable with respect to an entangled quantum state to determine the error-mitigated expectation value of the target observable with respect to the noisy quantum state.
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公开(公告)号：US12249404B2
公开(公告)日：2025-03-11
申请号：US17630482
申请日：2020-07-28
Applicant: Google LLC
Inventor： Ryan Babbush , William Huggins , Jarrod Ryan McClean
Abstract: Methods, systems and apparatus for measuring the energy of a quantum chemical system. In one aspect, a method includes obtaining a Hamiltonian describing the chemical system, where the Hamiltonian is expressed in an orthonormal basis; decomposing the Hamiltonian into a sum of terms where each term comprises a respective operator that effects a respective single particle basis rotation, and one or more particle density operators; repeatedly, for each group comprising terms with a same operator that effects a respective single particle basis rotation, measuring expectation values of the terms included in the group, comprising: performing the respective single particle basis rotation on a qubit system encoding a state of the chemical system; and measuring Jordan-Wigner transformations of the one or more particle density operators in the group to obtain a respective measurement result for the group; and determining the energy of the chemical system using the obtained measurement results.
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公开(公告)号：US20240013087A1
公开(公告)日：2024-01-11
申请号：US18036252
申请日：2021-11-11
Applicant: Google LLC
Inventor： William Huggins , Jarrod Ryan McClean
Abstract: Methods, systems and apparatus for determining an error-mitigated expectation value of a target observable with respect to a noisy quantum state. In one aspect a method includes obtaining multiple copies of the noisy quantum state; performing measurements on tensor products of M copies of the noisy quantum state to compute an expectation value of the target observable with respect to an entangled quantum state, wherein M?1 and eigenvalues corresponding to non-dominant eigenvectors of the noisy quantum state in the spectral decomposition of the entangled quantum state are suppressed exponentially in M; and using the computed expectation value of the target observable with respect to an entangled quantum state to determine the error-mitigated expectation value of the target observable with respect to the noisy quantum state.
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公开(公告)号：US20220254453A1
公开(公告)日：2022-08-11
申请号：US17630482
申请日：2020-07-28
Applicant: Google LLC
Inventor： Ryan Babbush , William Huggins , Jarrod Ryan McClean
Abstract: Methods, systems and apparatus for measuring the energy of a quantum chemical system. In one aspect, a method includes obtaining a Hamiltonian describing the chemical system, where the Hamiltonian is expressed in an orthonormal basis; decomposing the Hamiltonian into a sum of terms where each term comprises a respective operator that effects a respective single particle basis rotation, and one or more particle density operators; repeatedly, for each group comprising terms with a same operator that effects a respective single particle basis rotation, measuring expectation values of the terms included in the group, comprising: performing the respective single particle basis rotation on a qubit system encoding a state of the chemical system; and measuring Jordan-Wigner transformations of the one or more particle density operators in the group to obtain a respective measurement result for the group; and determining the energy of the chemical system using the obtained measurement results.
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