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公开(公告)号：US20250053849A1
公开(公告)日：2025-02-13
申请号：US18785890
申请日：2024-07-26
Applicant: Google LLC
Inventor： Thomas Eugene O'Brien , Rolando Diego Somma , Ryan Babbush
Abstract: Methods, systems, and apparatus for quantum simulation of a quantum system. In one aspect, a method includes, for an observable generated from a set of observables, wherein a commutator of each observable in the set of observables with the first Hamiltonian is equal to a combination of observables in the set of observables: encoding, by a quantum computer, a vector of coefficients of a time-dependent representation of the observable in a quantum state of a register of qubits; simulating, by the quantum computer, time evolution of the quantum state under a second Hamiltonian to obtain an evolved quantum state, wherein the second Hamiltonian comprises a matrix of complex weights in the linear combination of observables; measuring, by the quantum computer, the evolved quantum state; and post-processing, by a classical processor, obtained measurement results to obtain an expectation value of the observable.
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公开(公告)号：US12153645B2
公开(公告)日：2024-11-26
申请号：US18313051
申请日：2023-05-05
Applicant: Google LLC
Inventor： Ryan Babbush
Abstract: Methods, systems and apparatus for simulating quantum systems. In one aspect, a method includes the actions of obtaining a first Hamiltonian describing the quantum system, wherein the Hamiltonian is written in a plane wave basis comprising N plane wave basis vectors; applying a discrete Fourier transform to the first Hamiltonian to generate a second Hamiltonian written in a plane wave dual basis, wherein the second Hamiltonian comprises a number of terms that scales at most quadratically with N; and simulating the quantum system using the second Hamiltonian.
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公开(公告)号：US12147492B2
公开(公告)日：2024-11-19
申请号：US18049207
申请日：2022-10-24
Applicant: Google LLC
Inventor： Ryan Babbush
Abstract: Methods, systems and apparatus for estimating an expectation value of a quantum mechanical observable. In one aspect, a method includes identifying a first operator associated with the observable, wherein the first operator comprises a linear combination of terms. One or more constraints on expectation values of one or more of the terms in the linear combination are determined. A second operator is defined, wherein the second operator comprises a combination of the first operator and one or more of the determined constraints. The expectation value of the quantum mechanical observable is estimated using the second operator.
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公开(公告)号：US12086685B2
公开(公告)日：2024-09-10
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：US20240265284A1
公开(公告)日：2024-08-08
申请号：US18499879
申请日：2023-11-01
Applicant: Google LLC
Inventor： Ryan Babbush , Austin Greig Fowler
IPC: G06N10/00 , G06F15/16 , G06F30/20 , G06F30/337 , G06F30/373 , G06F30/398 , G06N10/40
CPC classification number: G06N10/00 , G06F15/16 , G06F30/20 , G06F30/337 , G06F30/373 , G06F30/398 , G06N10/40
Abstract: Methods, systems and apparatus for approximating a target quantum state. In one aspect, a method for determining a target quantum state includes the actions of receiving data representing a target quantum state of a quantum system as a result of applying a quantum circuit to an initial quantum state of the quantum system; determining an approximate quantum circuit that approximates the specific quantum circuit by adaptively adjusting a number of T gates available to the specific quantum circuit; and applying the determined approximate quantum circuit to the initial quantum state to obtain an approximation of the target quantum state.
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Patent Agency Ranking
公开(公告)号：US20230134825A1
公开(公告)日：2023-05-04
申请号：US18147144
申请日：2022-12-28
Applicant: Google LLC
Inventor： Ryan Babbush , Hartmut Neven
Abstract: Methods, systems, and apparatus for training quantum evolutions using sub-logical controls. In one aspect, a method includes the actions of accessing quantum hardware, wherein the quantum hardware includes a quantum system comprising one or more multi-level quantum subsystems; one or more control devices that operate on the one or more multi-level quantum subsystems according to one or more respective control parameters that relate to a parameter of a physical environment in which the multi-level quantum subsystems are located; initializing the quantum system in an initial quantum state, wherein an initial set of control parameters form a parameterization that defines the initial quantum state; obtaining one or more quantum system observables and one or more target quantum states; and iteratively training until an occurrence of a completion event.
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公开(公告)号：US20220391740A1
公开(公告)日：2022-12-08
申请号：US17859349
申请日：2022-07-07
Applicant: Google LLC
Inventor： Ryan Babbush
Abstract: Methods, systems, and apparatus for simulating a physical system. A Hamiltonian describing the physical system is transformed into a qubit Hamiltonian describing a corresponding system of qubits, the qubit Hamiltonian comprising a transformed kinetic energy operator. The evolution of the system of qubits under the qubit Hamiltonian is simulated, including simulating the evolution of the system of qubits under the transformed kinetic energy operator by applying a fermionic swap network to the system of qubits. The simulated evolution of the system of qubits under the qubit Hamiltonian is used to determine properties of the physical system.
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公开(公告)号：US20210271477A1
公开(公告)日：2021-09-02
申请号：US17257895
申请日：2019-07-03
Applicant: Google LLC
Inventor： Zhang Jiang , Ryan Babbush
Abstract: Methods, systems and apparatus for preparing arbitrary superposition quantum states of a quantum register on a quantum computer, the quantum state comprising a superposition of L computational basis states. In one aspect, a register of log L qubits is prepared in a weighted sum of register basis states, where each register basis state indexes a corresponding quantum state computational basis state, and the amplitude of each register basis state in the weighted sum of register basis states is equal to the amplitude of the corresponding computational basis state in the superposition of L computational basis states. A unitary transformation that maps the register basis states to the corresponding L computational basis states is then implemented, including, for each index 1 to L, controlling, by the register of log L qubits, transformation of the quantum system register state for the index to the corresponding computational basis state for the index.
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公开(公告)号：US20210157781A1
公开(公告)日：2021-05-27
申请号：US16976368
申请日：2019-04-19
Applicant: Google LLC
Inventor： Craig Gidney , Ryan Babbush
Abstract: Methods, systems and apparatus for performing indexed operations using a unary iteration quantum circuit. In one aspect, a method includes encoding an index value in an index register comprising index qubits; encoding the index value in a control register comprising multiple control qubits; and repeatedly computing and uncomputing the control qubits to perform, conditioned on the state of the control qubits, the operation on one or more target qubits corresponding to the index value, wherein during the encoding, computing and uncomputing: the multiple control qubits are made available in sequence, and the multiple control qubits correspond to a one-hot encoding of the encoded index value.
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公开(公告)号：US12299538B2
公开(公告)日：2025-05-13
申请号：US17257895
申请日：2019-07-03
Applicant: Google LLC
Inventor： Zhang Jiang , Ryan Babbush
Abstract: Methods, systems and apparatus for preparing arbitrary superposition quantum states of a quantum register on a quantum computer, the quantum state comprising a superposition of L computational basis states. In one aspect, a register of log L qubits is prepared in a weighted sum of register basis states, where each register basis state indexes a corresponding quantum state computational basis state, and the amplitude of each register basis state in the weighted sum of register basis states is equal to the amplitude of the corresponding computational basis state in the superposition of L computational basis states. A unitary transformation that maps the register basis states to the corresponding L computational basis states is then implemented, including, for each index 1 to L, controlling, by the register of log L qubits, transformation of the quantum system register state for the index to the corresponding computational basis state for the index.
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