Quantum data processing system
    1.
    发明授权

    公开(公告)号:US11915103B2

    公开(公告)日:2024-02-27

    申请号:US17731016

    申请日:2022-04-27

    Applicant: Google LLC

    CPC classification number: G06N10/70 G06N10/20 G06N20/00

    Abstract: Methods, systems, and apparatus for quantum data processing. In one aspect, a method includes storing, in a quantum memory, multiple copies of a quantum state, comprising, for each copy of the quantum state, i) probing, by an initialized quantum sensor, a target system to obtain an evolved quantum state of the quantum sensor, ii) transducing the evolved quantum state of the quantum sensor into a quantum state of a quantum buffer, iii) logically encoding the quantum state of the quantum buffer into a quantum error correcting code, and iv) moving the logically encoded quantum state of the quantum buffer into the quantum memory; loading the multiple copies of the quantum state in the quantum memory into a quantum computer; processing, by the quantum computer, the multiple copies of the quantum state to obtain a purified quantum state; and measuring the purified quantum state to determine properties of the target system.

    TECHNIQUES FOR OBTAINING ACCURATE DIAGONAL ELECTRONIC STRUCTURE HAMILTONIANS

    公开(公告)号:US20210035009A1

    公开(公告)日:2021-02-04

    申请号:US16976229

    申请日:2018-08-10

    Applicant: Google LLC

    Abstract: Methods, systems and apparatus for simulating a physical system described by an electronic structure Hamiltonian expressed in an orthonormal basis. In one aspect, a method includes decomposing the electronic structure Hamiltonian into a sum of sub-Hamiltonians, wherein each sub-Hamiltonian in the sum of sub-Hamiltonians is expressed in one of multiple bases; simulating evolution of the physical system using the decomposed electronic structure Hamiltonian; and using the simulated evolution of the physical system using the decomposed electronic structure Hamiltonian to determine properties of the physical system.

    Decoding errors using quantum subspace expansion

    公开(公告)号:US12261627B2

    公开(公告)日:2025-03-25

    申请号:US18473029

    申请日:2023-09-22

    Applicant: Google LLC

    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.

    Majorana loop stabilizer codes for error correction of fermionic quantum simulations

    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

    CPC classification number: G06N10/00 G06F15/16

    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.

    QUANTUM COMPUTING WITH KERNEL METHODS FOR MACHINE LEARNING

    公开(公告)号:US20220121998A1

    公开(公告)日:2022-04-21

    申请号:US17505202

    申请日:2021-10-19

    Applicant: Google LLC

    Abstract: Methods, systems, and apparatus for quantum machine learning. In one aspect, a method includes obtaining, by a quantum computing device, a training dataset of quantum data points; computing, by the quantum computing device, a kernel matrix that represents a similarity between the quantum data points included in the training dataset, comprising computing a value of a kernel function for each pair of quantum data points in the training dataset, wherein the kernel function is based on reduced density matrices for the quantum data points; and providing, by the quantum computing device, the kernel matrix to a classical processor, wherein the classical processor performs a training algorithm using the kernel matrix to construct a machine learning model.

    QUANTUM DATA PROCESSING SYSTEM
    6.
    发明公开

    公开(公告)号:US20240160987A1

    公开(公告)日:2024-05-16

    申请号:US18415439

    申请日:2024-01-17

    Applicant: Google LLC

    CPC classification number: G06N10/60 G06N10/40

    Abstract: Methods, systems, and apparatus for quantum data processing. In one aspect, a method includes storing, in a quantum memory, multiple copies of a quantum state, comprising, for each copy of the quantum state, i) probing, by an initialized quantum sensor, a target system to obtain an evolved quantum state of the quantum sensor, ii) transducing the evolved quantum state of the quantum sensor into a quantum state of a quantum buffer, iii) logically encoding the quantum state of the quantum buffer into a quantum error correcting code, and iv) moving the logically encoded quantum state of the quantum buffer into the quantum memory; loading the multiple copies of the quantum state in the quantum memory into a quantum computer; processing, by the quantum computer, the multiple copies of the quantum state to obtain a purified quantum state; and measuring the purified quantum state to determine properties of the target system.

    DECODING ERRORS USING QUANTUM SUBSPACE EXPANSION

    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

    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.

    INCREASING REPRESENTATION ACCURACY OF QUANTUM SIMULATIONS WITHOUT ADDITIONAL QUANTUM RESOURCES

    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

    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.

    MAJORANA LOOP STABILIZER CODES FOR ERROR CORRECTION OF FERMIONIC QUANTUM SIMULATIONS

    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

    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.

    Techniques for obtaining accurate diagonal electronic structure Hamiltonians

    公开(公告)号:US12265760B2

    公开(公告)日:2025-04-01

    申请号:US16976229

    申请日:2018-08-10

    Applicant: Google LLC

    Abstract: Methods, systems and apparatus for simulating a physical system described by an electronic structure Hamiltonian expressed in an orthonormal basis. In one aspect, a method includes decomposing the electronic structure Hamiltonian into a sum of sub-Hamiltonians, wherein each sub-Hamiltonian in the sum of sub-Hamiltonians is expressed in one of multiple bases; simulating evolution of the physical system using the decomposed electronic structure Hamiltonian; and using the simulated evolution of the physical system using the decomposed electronic structure Hamiltonian to determine properties of the physical system.

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