50 results about "Unitary operator" patented technology

A method and system for solving a computational problem using a hybrid data processor comprising a classical computer and quantum computer the method comprising receiving or determining information on one or more quantum circuits defining operations of a parameterized quantum model of a target function, the target function representing an approximate solution to the computational problem, preferably one or more differential equations and one or more associated boundary conditions, the one or more quantum circuits comprising one or more quantum feature maps for encoding one or more classical input features associated with the target function into the Hilbert space of the quantum register, wherein the one or more feature maps include one or more unitary operators defining a time evolution over a Hamiltonian, preferably a generator Hamiltonian, applied to quantum elements of the quantum register, the Hamiltonian evolution being parameterized by a first set of variational parameters and the one or more classical input features; and, determining the target function based on the parameterized quantum model and a loss function associated with the computational problem, the determining including varying the first set of variational parameters to determine a set of eigenfrequencies of the Hamiltonian which is optimized for the computational problem, the set of eigenfrequencies defining quantum modes, which the parameterized quantum.

A method and system for solving a computational problem using a hybrid data processor comprising a classical computer and quantum computer the method comprising receiving or determining information on one or more quantum circuits defining operations of a parameterized quantum model of a target function, the target function representing an approximate solution to the computational problem, preferably one or more differential equations and one or more associated boundary conditions, the one or more quantum circuits comprising one or more quantum feature maps for encoding one or more classical input features associated with the target function into the Hilbert space of the quantum register, wherein the one or more feature maps include one or more unitary operators defining a time evolution over a Hamiltonian, preferably a generator Hamiltonian, applied to quantum elements of the quantum register, the Hamiltonian evolution being parameterized by a first set of variational parameters and the one or more classical input features; and, determining the target function based on the parameterized quantum model and a loss function associated with the computational problem, the determining including varying the first set of variational parameters to determine a set of eigenfrequencies of the Hamiltonian which is optimized for the computational problem, the set of eigenfrequencies defining quantum modes, which the parameterized quantum.

A method of performing a quantum computation includes providing a quantum system comprising constituents; encoding a computational problem into a problem Hamiltonian of the quantum system; determining a constraint Hamiltonian of the quantum system; the constraint Hamiltonian a sum of summand constraint Hamiltonians; a ground state of a total Hamiltonian encodes a solution to the computational problem, the total Hamiltonian includes a sum of the problem Hamiltonian and the constraint Hamiltonian; determining a first subset S1 of the summand constraint Hamiltonians of the constraint Hamiltonian and a second subset S2 of the summand constraint Hamiltonians of the constraint Hamiltonian; performing N rounds of operations, wherein N≥2, each round includes preparing an initial quantum state and evolving the quantum system according to a sequence of unitary operators where the sequence includes problem-encoding unitary operators, constraint-enforcing unitary operators and unitary driver operators; and outputting a result of the quantum computation.

The invention is suitable for the technical field of computer application, and provides a method and device for generating a parameterized quantum circuit, terminal equipment and a storage medium, and the method comprises the steps: determining a Hamiltonian, an HF input quantum state and an electronic Hamiltonian according to the molecular information of a to-be-detected molecule; determining a parameterized quantum circuit architecture according to the Hamiltonian and the unitary operator; according to the parameterized quantum circuit architecture, generating an initial parameterized quantum circuit; constructing a loss function according to an HF input quantum state, an electronic Hamiltonian and a unitary operator; according to the initial parameterized quantum circuit and the loss function, a parameterized quantum circuit is generated, and the parameterized quantum circuit is used for measuring molecular ground state energy. Therefore, the initial parameterized quantum circuit is constructed through the Hamiltonian and the unitary operator, and the initial parameterized quantum circuit is trained and updated according to the loss function, so that the flexibility and expandability of the quantum circuit are improved, and the accuracy of molecular ground state energy measurement is improved.

The present disclosure provides a method for searching at least one locally marked element defined by marking parameters within a 2D lattice of a quantum system, wherein the quantum system is operated in discrete time and wherein the 2D lattice is arranged for supporting quantum random walks which are defined by quantum random walk parameters, the method having a pre-set time comprises the steps of calibrating the quantum system by: initializing a quantum state in the quantum system on at least one node; performing one step of the split-step quantum random walk on the quantum state; obtaining probability density information of the quantum state through overlap with eigenstates of a unitary operator; repeating previous two steps to determine quantum random walk parameters based on the highest probability in the probability density information of the quantum state. Thereafter, the method comprises the steps of searching the quantum system for the at least one marked element by: tuning the marking parameters of the at least one locally marked element; initializing a uniformly distributed quantum state on the entire quantum system; performing a plurality of split-step quantum random walks for the uniformly distributed quantum state; after the pre-set time has lapsed, converting the uniformly distributed quantum state of step vii) into an observable.

The invention provides an approximate quantum amplitude coding model based on a parameterized quantum circuit, which belongs to the technical field of artificial intelligence and comprises an analog quantum circuit and an implementation quantum circuit. The analog quantum circuit is composed of multiple layers, the number of the multiple layers is limited by the number of quantum bits, the analog quantum circuit is expressed through unitary transformation, and construction of the quantum circuit based on optimized unitary operators obtained in the analog quantum circuit is achieved; the analog quantum circuit is used for converting a pre-calculated amplitude coding quantum state into a fixed quantum state with the maximum fidelity; the implementation quantum circuit is used to encode a fixed quantum state into an approximate representation of an amplitude encoded quantum state through a conjugate transpose transform of the optimized analog quantum circuit. Through the approximate representation of the amplitude coding quantum state, the approximate quantum amplitude coding model significantly reduces the circuit depth of a quantum state preparation circuit and the complexity of a quantum gate, and improves the feasibility of implementation in large-scale quantum equipment with noise and the like.

The invention provides a digital quantum simulation method, which comprises the following steps of: performing symmetry analysis and subspace decomposition on a target Hamiltonian to obtain an effective Hamiltonian and a symmetry constraint condition; constructing a target unitary operator according to the effective Hamiltonian, and initializing a quantum circuit population of the target unitary operator; calculating entanglement characteristics of each quantum line in the quantum line population, performing structure variation on the quantum line population based on the entanglement characteristics, and performing line fragment crossing in combination with a symmetry constraint condition to obtain a candidate line set; performing line parameter optimization on the candidate line set based on the fidelity gradient to obtain an optimized line set, and extracting gate distribution structure features of the optimized line set; and non-uniform sampling is carried out on the optimized line set based on gate distribution structure characteristics to obtain a sampling line subset, an optimal quantum line is screened out from the sampling line subset based on the deviation between an experimental observation value and a theoretical expected value, and quantum simulation is carried out based on the optimal quantum line.

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.

The invention discloses an aircraft shape high-precision aerodynamic design method and device based on a quantum discrete adiabatic algorithm, and relates to the technical field of quantum computing. The method comprises the following steps: constructing a linear system model according to target aerodynamic data based on a computational fluid mechanics method; based on the cyclic shift basis matrix, according to the sparse coefficient matrix and the source item vector, performing block coding by using a linear combination unitary operator technology to obtain a block coding unitary operator; based on a preset iteration operator, constructing a walking operator according to the block coding unitary operator; according to the walking operator, line preparation is carried out through a cyclic calling method, and a quantum solving line is obtained; executing a quantum solving line, and measuring flow field quantum state information; and based on the target aerodynamic data, according to the flow field quantum state information, carrying out high-precision aerodynamic optimization design on the shape of the aircraft by utilizing an aerodynamic integration method. The high-precision aerodynamic design method for the aircraft profile is efficient and accurate based on the quantum discrete adiabatic algorithm.

The embodiment of the invention discloses a fluid steady-state characteristic determination method and a related device. The method comprises the steps that physical attributes and state parameters of fluid in a target system are acquired; according to the physical attributes and the state parameters, a fluid dynamic equation is constructed and discretized into a linear equation set, and the linear equation set is expressed as that the product of a coefficient matrix and a vector corresponding to an unknown quantity is equal to a constant vector; a quantum circuit is constructed according to the target unitary operator to solve the linear equation set, the steady-state characteristic of the fluid is obtained, the target unitary operator acts on the two registers, when the quantum state of one register represents any line of the coefficient matrix, the target unitary operator executes NOT gate operation on the other register, and when the quantum state of the other register represents any line of the coefficient matrix, the steady-state characteristic of the fluid is obtained. When the quantum state of one register represents the orthogonal complement space of any row of the coefficient matrix, the target unitary operator does not execute any operation on the other register. By adopting the embodiment of the invention, the steady-state characteristics of the fluid can be quickly determined.

A novel and useful hybrid quantum-classical mechanism for approximating geometric entanglement of multi-qubit pure states with noise mitigation in a quantum device. The mechanism applies the Higher-Order Power Method that approximates solutions to rank-1 tensor approximation and is executed virtually solely on a quantum computer with only angle computation performed on a classical computer. The mechanism iteratively estimates a closest separable state and an estimate of the corresponding entanglement eigenvalue in a quantum system. During each iteration, the mechanism applies a special unitary operator that skips one of the qubits. The state of the skipped qubit is recovered using one-qubit tomography to obtain updated angles used for a subsequent qubit. This procedure is repeated to converge to a final entanglement eigenvalue. A depolarizing noise mitigation procedure is also provided to generate a reduced noise estimate of geometric entanglement.

The invention relates to the technical field of power system load flow calculation and quantum calculation, in particular to a power system load flow calculation method and system based on quantum singular value transformation. According to the method, a target function needing to be approached by the QSVT and an approximation polynomial meeting parity and bounded performance are designed, and the polynomial is converted into a QSP phase sequence; and then a QSVT circuit is built in combination with the unitary operator U and the phase sequence to solve a quantum state, correction values of the voltage and the phase angle in the quantum state are extracted through quantum amplitude estimation, and the correction values are fed back to a classic controller for iteration, so that the voltage and the phase angle of the power system are updated until load flow calculation is converged. According to the method, polynomial approximation and phase sequence optimization are realized by using the QSVT framework, the calculation complexity is reduced, and the problem of convergence is avoided.

An information processing device judges, with respect to at least any one of multiple quantum bits in a quantum circuit, whether a corresponding first-order term is present in a cost operator. When the first-order term corresponding to any one of the plurality of quantum bits is not present the information processing device updates at least any one of the cost unitary operators so that the first-order term corresponding to the any one of the quantum bits and to which a new first variational parameter is assigned is included in the exponent part. The information processing device solves a combinatorial optimization problem based on multiple mixer unitary operators and the multiple cost unitary operators after updating at least the any one of the cost unitary operators.

A computer-implemented method for determining a quantum circuit appliable on n quantum elements The method comprises obtaining a first permutation entity, wherein said first permutation entity is indicative of a first permutation P̂n said first permutation P̂n comprising at least one permutation or partial permutation appliable to a sequence of digits of length n, and determining a second permutation entity, wherein said second permutation entity is indicative of a quantum circuit appliable on n quantum elements, wherein the quantum circuit corresponds to the first permutation P̂n, said first permutation comprising at least one permutation or partial permutation appliable to a sequence of digits of length n, said quantum circuit corresponding to a sequence of unitary operators.

The present disclosure provides a method, apparatus, device, and storage medium for determining quantum state components, relating to the field of computer technology, particularly to the field of quantum computing technology. A specific implementation scheme is as follows: a component analysis step, including: in a current sub-process, when the total initial quantum state is used as the total input quantum state of a block-coded quantum circuit corresponding to a simulated block-coded unitary operator #imgabs0#, obtaining a first characteristic phase λ corresponding to the block-coded unitary operator #imgabs1#, and a first characteristic state corresponding to the first characteristic phase λ; when it is determined that the measurement result corresponding to the target auxiliary register in the block-coded quantum circuit meets a preset requirement, obtaining first component information of the target quantum state ρ based on the first characteristic phase λ and the first characteristic state corresponding to the first characteristic phase λ; the first component information includes at least one of the following: a target eigenvalue of the target quantum state ρ, and a target eigenstate corresponding to the target eigenvalue.

The present invention relates to a quantum convolutional neural network system and a method of operation for processing quantum states to estimate intrinsic properties. More specifically, the invention relates to a technique for transforming an input quantum state, measuring the first qubit, processing the state based on the measurement result, and calculating the intrinsic properties of the transformed state. The present invention provides a quantum convolutional neural network system composed of a learning unit, a quantum layer structure unit, and a computation unit. The learning unit receives an input quantum state and is designed to maximize the measurement probability of the first qubit by learning a unitary operator based on a local cost function. The learned unitary operator transforms the quantum state through the quantum layer structure unit; the transformed state is then measured by the first qubit, and the residual state is transmitted to the next layer or re-measured based on the measurement result. The present invention provides a technique that efficiently processes input data during the quantum neural network learning process and enables accurate analysis of quantum states and efficient dimensionality reduction. Through this, high performance and reliability can be secured in various application fields such as quantum information theory, quantum data analysis, and quantum machine learning.

The invention discloses a quantum state preparation method and device, equipment and a storage medium, and relates to the technical field of quantum. The method comprises the following steps: acquiring n quantum bits under grid limitation; dividing the n quantum bits into a plurality of quantum bit sets meeting sub-grid limitation; an allocation operator subset, a permutation operator subset and a unitary operator subset are determined, the allocation operator subset and the permutation operator subset are used for allocating the Hamming weight of the first quantum state to the multiple quantum bit sets and enabling the multiple quantum bit sets to be mutually entangled, and a permutation operator is used for exchanging the quantum states between the two quantum bit sets; under the indication of the preparation operator architecture, determining a quantum state preparation operator based on the allocation operator subset, the replacement operator subset and the unitary operator subset; and acting the quantum state preparation operator on the n quantum bits to evolve the quantum states of the n quantum bits from the initial quantum state to the first quantum state. According to the invention, the circuit depth of the quantum state preparation circuit can be reduced.

Embodiments of the present application disclose a fluid steady-state characteristic determination method and related device, the method comprising: obtaining physical properties and state parameters of a fluid in a target system; constructing a fluid dynamics equation according to the physical properties and the state parameters, and discretizing the fluid dynamics equation into a linear equation set, the linear equation set being expressed as a product of a coefficient matrix and a vector corresponding to unknown quantities being equal to a constant vector; constructing a quantum circuit to solve the linear equation set according to a target unitary operator, and obtaining steady-state characteristics of the fluid, the target unitary operator acting on two registers, when a quantum state of one of the registers represents an arbitrary row of the coefficient matrix, the target unitary operator performs a NOT operation on the other register, and when the quantum state of one of the registers represents an orthogonal complement space of an arbitrary row of the coefficient matrix, the target unitary operator does not perform any operation on the other register. By using the embodiments of the present application, the steady-state characteristics of the fluid can be quickly determined.

The invention discloses an efficient fault-tolerant Trout simulation of molecular Hamiltonian. A method performed by a quantum computing device, the method comprising: applying a quantum circuit to a qubit system included in the quantum computing device, where the quantum circuit implements a time-evolved Trout step, comprising: applying a multi-layer quantum logic gate to the qubit system, where the quantum logic gate comprises a Trout step of a Trout step of a Trout step of a Trout step of a Trout step of a Trout step of a Trout step of a Trout step of a Trout step of a Trout step of a Trout step; each application of a layer in the multilayer evolves the qubit system under unitary operators generated by respective sets of interaction terms in a qubit Hamiltonian representing the Fermi system, and each layer in the multilayer quantum logic gate includes rotation operations having the same rotation angle, applying a layer of a quantum logic gate to the qubit system includes correspondingly applying a Hamming weight to a rotation in the layer of the quantum logic gate; and measuring the evolved qubit system to determine the energy of the Fermi system.

Methods, systems, and devices for learning quantum systems via non-temporally ordered correlators. In one aspect, a method includes measuring, by a control and measurement system, a non-temporally ordered correlator value of a quantum system including a plurality of qubits, where the plurality of qubits includes a probe qubit and one or more other qubits. To measure non-temporally ordered correlator values, the probe qubit is prepared in an initial state. For time t, forward time evolution is performed on the quantum system. A unitary operator is applied to one or more qubits in the quantum system. For time t, backward time evolution is performed on the quantum system, and the probe qubits are measured to obtain non-temporally ordered correlator values. The classical computing device processes the measured non-temporally ordered correlator values to determine a property of the quantum system.

Methods, systems, and apparatus for quantum phase estimation. In one aspect, an apparatus includes a quantum circuit comprising a first quantum register comprising at least one ancilla qubit, quantum gates, comprising at least (i) two Hadamard gates, (ii) a phase gate, (iii) a unitary operator, and (iv) a measurement operator, a second quantum register comprising one or more qubits, wherein the second quantum register is prepared in an arbitrary quantum state that is not an eigenstate of the unitary operator; and a phase learning system, configured to perform phase estimation experiments on the quantum circuit, comprising repeatedly measuring the state of an ancilla qubit for each phase estimation experiment to determine an expectation value of the state of the ancilla qubit and learn phases of the eigenvalues of the unitary operator.

The invention relates to a particle-ball-based quantum principal component analysis multi-kernel K mean value method, and belongs to the technical field of quantum calculation and machine learning crossing. According to the method, an original data set is compressed into a granular ball data set through classical calculation so as to reduce the data scale, a plurality of kernel matrixes are quickly generated through a polymorphic exchange test by utilizing quantum calculation parallelism, and a core characteristic value is decomposed and reconstructed into a quantum principal component analysis task. Using unitary operator linear combination and quantum phase estimation to realize exponential acceleration solution, and finally performing alternative optimization on clustering distribution and kernel weight in the mixed quantum classical framework until convergence. According to the method, the bottleneck problem of high eigenvalue decomposition calculation complexity in a multi-core K-means algorithm is effectively solved, and an excellent clustering effect is kept while calculation time and resource consumption are remarkably reduced.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for quantum phase estimation. In one aspect, a method includes: performing a plurality of phase estimation experiments on an ancilla qubit, wherein each experiment includes: preparing the ancilla qubit in an initial quantum state; applying a unitary operator to the ancilla qubit prepared in the initial quantum state and a quantum register prepared in an arbitrary quantum state one or more times; and measuring the state of the ancilla qubit; determining an expectation value of the state of the ancilla qubit based on results of the plurality of phase estimation experiments; and inferring a phase of an eigenvalue of the unitary operator by optimizing a mixture model representing probabilities of the state of the ancilla qubit based on the determined expectation value of the state of the ancilla qubit and the measured state of the ancilla qubit.

The invention relates to methods and systems for generation of an optimized ansatz (Ψ(m)) wave-function, said computer implemented method comprising operating a system comprising quantum computational means and classical computational means, said method comprising: o Generating analytic functions of a parameter Θ from an objective function; o Selecting several angles values of the parameter Θ to generate, from the analytic functions of the parameter Θ; o On the quantum computational means, computing unknown operator expectation values of the objective function at the several selected angles values; o On the classical computational means, computing the objective function for any unitary operator (B), any angle of the parameter θ, o Appending the resulting locally optimal unitary operator to the left of the current ansatz wave-function |Ψ(curr)), preferably to generate an optimized ansatz (Ψ(m)) wave-function.

The present invention provides a method and device for analyzing the properties of unitary operators in a distributed scenario, and relates to the field of quantum information technology. The method includes: using the unitary operator of a quantum terminal to perform a rotation transformation on the initial quantum state of the quantum terminal to obtain the intermediate quantum state of the quantum terminal; using a plurality of unitary matrices included in a unitary matrix set to synchronously measure the intermediate quantum states of the plurality of quantum terminals to obtain a plurality of inner product results, wherein each inner product result is obtained based on a set of measurement results of the plurality of quantum terminals; based on the plurality of inner product results, obtaining the property analysis results of the quantum terminal, wherein the property analysis results of the quantum terminal characterize the similarity between the unitary operators included in the plurality of quantum terminals.

This invention relates to the fields of power system power flow calculation and quantum computing, and in particular to a power system power flow calculation method and system based on quantum singular value transformation (QSVT). The invention designs the objective function to be approximated by QSVT and the approximation polynomial satisfying parity and boundedness, converting the polynomial into a QSP phase sequence. Then, a QSVT circuit is constructed using the unitary operator U and the phase sequence to solve for the quantum state. Corrections for voltage and phase angle in the quantum state are extracted through quantum amplitude estimation and fed back to the classical controller for iteration to update the voltage and phase angle of the power system until the power flow calculation converges. This invention utilizes the QSVT framework to achieve polynomial approximation and phase sequence optimization, reducing computational complexity and avoiding convergence issues.

The application discloses a kind of method for realizing distributed quantum amplitude amplification and related equipment, method includes: the initial success probability of quantum state is quantified based on target unitary operator, and configuration unitary operator is obtained from target unitary operator based on division parameter;Based on division parameter, Boolean function is split into the subfunction of preset quantity and sequentially distributed to each quantum node;Based on configuration unitary operator, the probability upper limit value of each quantum node is quantified using amplitude estimation;According to probability upper limit value, iteration number is obtained, and according to initial success probability, iteration upper limit is obtained;Based on iteration number, the measurement string corresponding to quantum node is iteratively output by quantum amplitude amplification algorithm, and then target string is verified and determined;Quantum operation result is obtained by summarizing the target string corresponding to all quantum nodes.The application can effectively avoid the dependence of existing distributed quantum computation on quantum communication means such as quantum teleportation, and can be widely applied in the field of data processing.

An information processing program for causing a computer to execute a process including: setting first and second functions, for a quantum circuit used when solving a combinatorial optimization problem and including, for each layer, a first partial circuit representing an action of a mixer unitary operator and a second partial circuit representing an action of a cost unitary operator, the first function representing a first variational parameter of the first partial circuit, the second function representing a second variational parameter of the second partial circuit; and calculating a solution to the combinatorial optimization problem by updating a value of a first transformation parameter related to the first function and a value of a second transformation parameter related to the second function so as to optimize an expected value of a cost function corresponding to the combinatorial optimization problem by using the quantum circuit after setting the first function and the second function.

The invention discloses a quantum self-attention model and method based on complex value weight. The model comprises at least one hierarchical complex linear combination framework of unitary operators, at least one quantum complex similarity module and an output module, the multi-linear combination framework of the unitary operators comprises at least one multi-linear combination module of the first-level unitary operators, and the multi-linear combination module of the first-level unitary operators comprises a quantum feature mapping module and a quantum complex value weight embedding module; wherein the quantum complex value weight embedding module is used for converting a real part and an imaginary part of a quantum self-attention complex value weight into an amplitude and a phase respectively, and embedding the amplitude and the phase into a quantum circuit through coding; a complex linear combination module of a first-level unitary operator, which is used for carrying out complex linear combination on the quantum value states based on the quantum complex value weight embedding module to obtain self-attention weighted quantum states; and the output module is used for integrating the global context into the feature representation based on the self-attention weighted quantum states, so that the difference between the quantum states is accurate, and the model expressive power is enhanced.

A quantum state preparation circuit generation method and apparatus, a device, and a storage medium, relating to the technical field of quantum. The method comprises: acquiring n quantum bits under a mesh constraint (201); dividing the n quantum bits into a plurality of quantum bit sets satisfying a sub-mesh constraint (202); determining an allocation operator set, a permutation operator set, an unitary operator set, and a preparation operator architecture, the allocation operator set being combined with the permutation operator set to allocate the Hamming weight of a first quantum state to the plurality of quantum bit sets and enabling the plurality of quantum bit sets to be entangled with each other, and permutation operators being used for exchanging the quantum states of two quantum bit sets (203); and, on the basis of the preparation operator architecture, combining the allocation operator set, the permutation operator set and the unitary operator set to obtain quantum state preparation operators, a quantum state preparation circuit corresponding to each quantum state preparation operator being used for evolving the quantum states of the n quantum bits into the first quantum state (204). The present application can reduce the circuit depth of quantum state preparation circuits.