Method and application of electronic structure determination based on Bose sampling

Abstract

The present disclosure provides a method and application for determining an electronic structure based on Bose sampling, which can be applied to the field of quantum computer technology. The determination method includes: generating a current wave function corresponding to a target molecule using a linear optical interferometer; determining a current Hamiltonian corresponding to the target molecule using a preset target chemical calculation method; determining a current energy value using the current wave function and the current Hamiltonian; updating a current phase parameter of the linear optical interferometer and a current calculation parameter of the target chemical calculation method using a preset optimization method based on the current energy value, obtaining an updated phase parameter of the linear optical interferometer and an updated calculation parameter of the target chemical calculation method; and iteratively performing the above operations until the current energy value satisfies a preset iteration condition, and using the wave function generated by the linear optical interferometer when the preset iteration condition is satisfied as the target wave function of the target molecule.

Description

Technical Field

[0001] The present disclosure relates to the field of quantum computer technology, and in particular to a method for determining an electronic structure based on Bose sampling and its application. Background Art

[0002] Quantum computers are devices that use quantum states to encode and compute information. Compared to traditional computers, their computational efficiency can be exponentially improved due to properties such as quantum superposition and entanglement, offering potential applications in solving complex problems.

[0003] In related technologies, electronic structure problems are typically solved using classical chemical calculations via quantum computers. The problem to be solved is first encoded in a Hamiltonian, quantum states are prepared using parameterized quantum wires, and the objective function is optimized using classical optimization algorithms.

[0004] In the process of realizing the inventive concept disclosed herein, the inventors discovered that there are at least the following problems in the related art: the methods used in the related art to deal with electronic structure problems have the problem of low solution accuracy. Summary of the Invention

[0005] In response to the above technical problems, the present disclosure provides a method and application for determining electronic structure based on Bose sampling to at least partially solve at least one of the above technical problems.

[0006] In order to solve the above technical problems, the technical solutions disclosed in this disclosure are as follows:

[0007] As one aspect of the present disclosure, a method for determining an electronic structure based on Bose sampling is provided, comprising:

[0008] generating a current wave function corresponding to the target molecule using a linear optical interferometer, wherein the current wave function represents a wave function of the target molecule generated by the linear optical interferometer under current phase parameters;

[0009] Determining a current Hamiltonian corresponding to the target molecule using a preset target chemical calculation method, wherein the current Hamiltonian represents the Hamiltonian of the target molecule generated by the target chemical calculation method under current calculation parameters;

[0010] Determining a current energy value using the current wave function and the current Hamiltonian, wherein the current energy value represents an energy value corresponding to the current Hamiltonian under the current wave function;

[0011] updating the current phase parameters of the linear optical interferometer and the current calculation parameters of the target chemical calculation method using a preset optimization method based on the current energy value, to obtain updated phase parameters of the linear optical interferometer and updated calculation parameters of the target chemical calculation method; and

[0012] The above operation is iteratively performed until the current energy value satisfies a preset iteration condition, and when the preset iteration condition is satisfied, the wave function generated by the linear optical interferometer is used as the target wave function of the target molecule, wherein the target wave function is used to determine the electronic structure of the target molecule.

[0013] According to an embodiment of the present disclosure, the above method further includes:

[0014] determining an initial Hamiltonian and an initial reference state corresponding to the target molecule according to the electronic structure of the target molecule;

[0015] The above-mentioned use of a linear optical interferometer to generate a current wave function corresponding to the target molecule includes:

[0016] Updating the initial reference state using the linear optical interferometer to obtain the current wave function;

[0017] The above-mentioned determination of the current Hamiltonian corresponding to the above-mentioned target molecule using the preset target chemical calculation method includes:

[0018] The initial Hamiltonian is transformed using the target chemical calculation method to obtain the current Hamiltonian.

[0019] According to an embodiment of the present disclosure, the above-mentioned updating of the above-mentioned initial reference state using the above-mentioned linear optical interferometer to obtain the above-mentioned current wave function includes:

[0020] Determining initial light source input information of the linear optical interferometer according to the initial reference state;

[0021] A single photon source is input into the linear optical interferometer according to the initial light source input information, and the current wave function is output.

[0022] According to an embodiment of the present disclosure, determining the current energy value using the current wave function and the current Hamiltonian includes:

[0023] Measuring the information of the current wave function using a homodyne measurement method;

[0024] The current energy value is determined based on the information of the current wave function and the Hamiltonian.

[0025] According to an embodiment of the present disclosure, the above method further includes:

[0026] Before the current wave function corresponding to the target molecule is generated by the linear optical interferometer, a set of phase parameters is randomly generated to obtain initial phase parameters;

[0027] The initial phase parameter is used as the current phase parameter of the linear optical interferometer.

[0028] According to an embodiment of the present disclosure, the above method further includes:

[0029] Before determining the current Hamiltonian corresponding to the target molecule using a preset target chemical calculation method, randomly generating a set of calculation parameters to obtain initial calculation parameters;

[0030] The initial calculation parameters are used as the current calculation parameters of the target chemical calculation method.

[0031] According to an embodiment of the present disclosure, the phase parameter of the linear optical interferometer includes at least one of the following: wave plate angle, wave plate position, and transmittance.

[0032] According to an embodiment of the present disclosure, the above-mentioned preset optimization method includes: gradient descent method, particle swarm swimming method or second-order quasi-Newton method.

[0033] According to an embodiment of the present disclosure, the target chemical calculation method includes: Hartley-Fock method, coupled cluster or density functional theory.

[0034] As another aspect of the present disclosure, a method for predicting the chemical reaction rate of the target molecule using the target wave function obtained by the above method is provided.

[0035] According to an embodiment of the present disclosure, a linear optical interferometer is used to generate a current wave function corresponding to a target molecule, and a pre-set target chemical calculation method is used to determine a current Hamiltonian corresponding to the target molecule. The current wave function and the current Hamiltonian are then used to determine a current energy value corresponding to the current Hamiltonian under the current wave function. The parameters of the linear interferometer and the target chemical calculation method are then updated by optimizing the current energy value. After multiple iterations according to the above method, the wave function generated by the linear interferometer is used as the target wave function of the target molecule. Because the embodiments of the present disclosure combine a linear optics-based Bose sampling quantum computer with quantum computational chemistry methods, the bosonic resources in Bose sampling can enhance the accuracy of classical chemical calculation methods, thereby improving the accuracy of solving electronic structure problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flowchart of a method for determining an electronic structure according to an embodiment of the present disclosure is schematically shown;

[0037] Figure 2Schematically shows a flow chart of a method for determining an electronic structure according to another embodiment of the present disclosure;

[0038] Figure 3 A principle diagram schematically illustrating a method for determining an electronic structure according to an embodiment of the present disclosure; and

[0039] Figure 4 The figure schematically shows the solution results obtained by using different methods. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0041] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0042] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0043] When expressions such as "at least one of A, B and C, etc." are used, they should generally be interpreted in accordance with the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0044] Quantum computers are devices that use quantum states to encode information and perform computations. Compared to traditional computers, their computational efficiency can be exponentially improved due to properties such as quantum superposition and entanglement, offering potential applications in solving complex problems. Currently, specialized Bose sampling quantum computers based on linear optics have garnered widespread attention in both scientific research and the corporate sector.

[0045] In the related art, electronic structure problems are generally solved using classical chemical calculation methods via quantum computers. Classical-quantum hybrid variational algorithms, particularly variational quantum ground state solvers, are among the few algorithms that can be run on current quantum computers. Variational quantum ground state solvers typically encode the problem in a Hamiltonian, prepare quantum states using parameterized quantum wires, and optimize the objective function using classical optimization algorithms.

[0046] However, the precise solution of quantum computing chemistry problems requires exponentially large resource consumption on classical computers, and the methods used to deal with electronic structure problems in related technologies have the problem of low solution accuracy.

[0047] In view of this, the present disclosure addresses the above technical problems and provides a method for determining an electronic structure based on Bose sampling, comprising: generating a current wave function corresponding to a target molecule using a linear optical interferometer, wherein the current wave function represents the wave function of the target molecule generated by the linear optical interferometer under current phase parameters; determining a current Hamiltonian corresponding to the target molecule using a preset target chemical calculation method, wherein the current Hamiltonian represents the Hamiltonian of the target molecule generated by the target chemical calculation method under current calculation parameters; determining a current energy value using the current wave function and the current Hamiltonian, wherein the current energy value represents the energy value corresponding to the current Hamiltonian under the current wave function; updating the current phase parameters of the linear optical interferometer and the current calculation parameters of the target chemical calculation method using a preset optimization method based on the current energy value to obtain updated phase parameters of the linear optical interferometer and updated calculation parameters of the target chemical calculation method; and iteratively performing the above operations until the current energy value meets a preset iteration condition, and using the wave function generated by the linear optical interferometer when the preset iteration condition is met as the target wave function of the target molecule.

[0048] Figure 1 The flowchart of the method for determining the electronic structure according to an embodiment of the present disclosure is schematically shown.

[0049] like Figure 1 As shown, the method for determining the electronic structure of this embodiment includes operations S110 to S150.

[0050] In operation S110 , a current wave function corresponding to a target molecule is generated using a linear optical interferometer, wherein the current wave function represents a wave function of the target molecule generated by the linear optical interferometer under a current phase parameter.

[0051] According to an embodiment of the present disclosure, the linear optical interferometer is a programmable linear optical interferometer, that is, the phase parameter of the linear optical interferometer can be adjusted.

[0052] According to an embodiment of the present disclosure, the current phase parameter includes any parameter that can affect the wave function of the target molecule. Since different linear optical interferometers have different phase parameters, the embodiment of the present disclosure does not limit the phase parameter of the linear optical interferometer.

[0053] According to an embodiment of the present disclosure, since the wave function generated by the linear optical interferometer is related to the phase parameter, the current wave function corresponds to the current phase parameter of the linear optical interferometer.

[0054] In one embodiment, the phase parameter of the linear optical interferometer may include at least one of a wave plate angle, a wave plate position, and a transmittance.

[0055] In operation S120 , a current Hamiltonian corresponding to the target molecule is determined using a preset target chemical calculation method, wherein the current Hamiltonian represents the Hamiltonian of the target molecule generated by the target chemical calculation method under current calculation parameters.

[0056] According to an embodiment of the present disclosure, the target chemical calculation method may include any classical chemical calculation method. For example, the target chemical calculation method may include at least one of the Hartree-Fock method, coupled clusters, or density functional theory.

[0057] In operation S130, a current energy value is determined using the current wave function and the current Hamiltonian, where the current energy value represents an energy value corresponding to the current Hamiltonian under the current wave function.

[0058] In operation S140, a preset optimization method is used to update the current phase parameters of the linear optical interferometer and the current calculation parameters of the target chemical calculation method based on the current energy value to obtain updated phase parameters of the linear optical interferometer and updated calculation parameters of the target chemical calculation method.

[0059] According to an embodiment of the present disclosure, the preset optimization method may include, for example, a gradient descent method, a particle swarm swimming method, or a second-order quasi-Newton method.

[0060] In operation S150, the above operations are iteratively performed until the current energy value satisfies a preset iteration condition, and the wave function generated by the linear optical interferometer when the preset iteration condition is satisfied is used as the target wave function of the target molecule, wherein the target wave function is used to determine the electronic structure of the target molecule.

[0061] According to an embodiment of the present disclosure, the preset iteration condition may include, for example, that the current energy value reaches a threshold or converges.

[0062] According to an embodiment of the present disclosure, a linear optical interferometer is used to generate a current wave function corresponding to a target molecule, and a pre-set target chemical calculation method is used to determine a current Hamiltonian corresponding to the target molecule. The current wave function and the current Hamiltonian are then used to determine a current energy value corresponding to the current Hamiltonian under the current wave function. The parameters of the linear interferometer and the target chemical calculation method are then updated by optimizing the current energy value. After multiple iterations according to the above method, the wave function generated by the linear interferometer is used as the target wave function of the target molecule. Because the embodiments of the present disclosure combine a linear optics-based Bose sampling quantum computer with quantum computational chemistry methods, the bosonic resources in Bose sampling can enhance the accuracy of classical chemical calculation methods, thereby improving the accuracy of solving electronic structure problems.

[0063] According to an embodiment of the present disclosure, the above method also includes: determining the initial Hamiltonian and initial reference state corresponding to the target molecule based on the electronic structure of the target molecule; wherein, generating the current wave function corresponding to the target molecule using a linear optical interferometer includes: updating the initial reference state using a linear optical interferometer to obtain the current wave function; determining the current Hamiltonian corresponding to the target molecule using a pre-set target chemical calculation method includes: transforming the initial Hamiltonian using the target chemical calculation method to obtain the current Hamiltonian.

[0064] According to an embodiment of the present disclosure, the initial Hamiltonian corresponding to the target molecule is determined based on the electronic structure of the target molecule. For example, the Hamiltonian can be determined based on the electronic structure using any classical chemical method. For example, the initial Hamiltonian of the target molecule can be determined using the Hartley-Fock method, or using a coupled cluster or density functional method.

[0065] According to an embodiment of the present disclosure, the initial reference state may be a wave function that is similar to a target wave function of a target molecule.

[0066] According to an embodiment of the present disclosure, the initial reference state corresponding to the target molecule is determined according to the electronic structure of the target molecule. For example, the initial reference state corresponding to the target molecule can be determined artificially according to the electronic structure, or the initial reference state corresponding to the target molecule can be generated by a linear optical interferometer.

[0067] According to an embodiment of the present disclosure, using a linear optical interferometer to update the initial reference state to obtain the current wave function includes: determining the initial light source input information of the linear optical interferometer based on the initial reference state; inputting a single photon source into the linear optical interferometer based on the initial light source input information, and outputting the current wave function.

[0068] According to an embodiment of the present disclosure, the initial light source input information may include, for example, orbital position information of the single photon source.

[0069] According to an embodiment of the present disclosure, the method further includes initializing phase parameters of the linear interferometer before generating a current wave function corresponding to the target molecule using the linear optical interferometer. The method for initializing the phase parameters of the linear interferometer may include randomly generating a set of phase parameters to obtain initial phase parameters; and using the initial phase parameters as the current phase parameters of the linear optical interferometer.

[0070] According to an embodiment of the present disclosure, the method further includes initializing calculation parameters of the target chemical calculation method before determining the current Hamiltonian corresponding to the target molecule using the preset target chemical calculation method. Initializing the calculation parameters of the target chemical calculation method may include randomly generating a set of calculation parameters to obtain initial calculation parameters; and using the initial calculation parameters as current calculation parameters of the target chemical calculation method.

[0071] According to an embodiment of the present disclosure, determining the current energy value using the current wave function and the current Hamiltonian includes: measuring information of the current wave function using a homodyne measurement method; and determining the current energy value based on the information of the current wave function and the Hamiltonian.

[0072] Figure 2 The flowchart of the method for determining the electronic structure according to another embodiment of the present disclosure is schematically shown.

[0073] like Figure 2 As shown, the method for determining the electronic structure of this embodiment includes operations S201 to S212.

[0074] In operation S201 , an initial Hamiltonian and an initial reference state corresponding to a target molecule are determined according to the electronic structure of the target molecule.

[0075] In operation S202, a set of phase parameters is randomly generated to obtain initial phase parameters.

[0076] In operation S203 , the initial phase parameter is used as the current phase parameter of the linear optical interferometer.

[0077] In operation S204 , the initial reference state is updated using a linear optical interferometer to obtain a current wave function.

[0078] In operation S205, information of the current wave function is measured using a homodyne measurement method.

[0079] In operation S206 , a set of calculation parameters is randomly generated to obtain initial calculation parameters.

[0080] In operation S207 , the initial calculation parameters are used as current calculation parameters of the target chemical calculation method.

[0081] In operation S208 , the initial Hamiltonian is transformed using a target chemical calculation method to obtain a current Hamiltonian.

[0082] In operation S209 , a current energy value is determined based on the information of the current wave function and the Hamiltonian.

[0083] In operation S210, it is determined whether the current energy value satisfies a preset iteration condition. If it is determined that the current energy value satisfies the preset iteration condition, operation S211 is performed; if it is determined that the current energy value does not satisfy the preset iteration condition, operation S212 is performed.

[0084] In operation S211 , a wave function generated by the linear optical interferometer when a preset iteration condition is satisfied is used as a target wave function of the target molecule.

[0085] In operation S212, the current phase parameters of the linear optical interferometer and the current calculation parameters of the target chemical calculation method are updated based on the current energy value using a preset optimization method to obtain the updated phase parameters of the linear optical interferometer and the updated calculation parameters of the target chemical calculation method, and then operations S204-S210 are performed.

[0086] According to the embodiments of the present disclosure, electronic structure problems belong to fermions, and linear optics belongs to bosons. This solution combines Bose sampling with quantum computational chemistry by corresponding the 0, 1 photon occupation state of each bosonic orbital to the 0, 1 electron occupation state of the fermion orbital, so that bosonic resources can enhance the accuracy of classical computational chemistry methods, thereby improving the accuracy of solving electronic structure problems.

[0087] Figure 3 The principle diagram of the method for determining the electronic structure according to an embodiment of the present disclosure is schematically shown.

[0088] like Figure 3 As shown, a second quantization is performed based on the electronic structure problem 301 of the target molecule, i.e., a process of selecting a basis vector set 302, to obtain a second quantized Hamiltonian 303 and an initial reference state 304. The second quantized Hamiltonian 303 is then calculated using a classical chemical calculation method 305 to output a transformed Hamiltonian 306, i.e., the current Hamiltonian. Simultaneously, the initial reference state 304 is input into a linear optical interferometer 307 to generate a current wave function 308. A current energy value 310 is then determined using a homodyne measurement method 309 based on the transformed Hamiltonian 306 and the current wave function 308. Based on the current energy value 310, a classical optimization method 311 is used to optimize the phase parameters of the linear optical interferometer 307 and the calculation parameters of the classical chemical method 305. These steps are iteratively performed until the current energy value 310 reaches a threshold or converges, and the wave function generated by the linear optical interferometer 307 when the current energy value 310 reaches the threshold or converges is used as the target wave function of the target molecule.

[0089] It should be noted that the classical chemical calculation method 305 can adopt the Hartley-Fock method Configuration Interaction Method The linear optical interferometer 307 can be used express.

[0090] According to an embodiment of the present disclosure, the transformed Hamiltonian 306 may be determined using, for example, formula (1).

[0091]

[0092] in,

[0093] β represents the calculation parameter in the classical chemical calculation method;

[0094] represents the classical chemical calculation method;

[0095] represents the transformation Hamiltonian;

[0096] Represents classical chemical calculation method The transposed conjugate of .

[0097] The above-mentioned method for determining the electronic structure is further explained below with reference to specific embodiments.

[0098] Example

[0099] This example uses lithium hydride as the target molecule and employs the methods provided in this disclosure to solve the electronic structure problem for the lithium hydride molecule. The Hamiltonian for the lithium hydride molecule corresponds to a mode 6 linear optical interferometer. The Hartley-Fock method is used as the classical chemical calculation method.

[0100] Comparative Example

[0101] The electronic structure problem of lithium hydride is solved using relevant technologies. Specifically, the Hartley-Fock method is used as a classical chemical method to solve the electronic structure problem of lithium hydride.

[0102] Figure 4 The figure schematically shows the solution results obtained by using different methods.

[0103] like Figure 4 As shown, the solution for lithium hydride obtained using the method provided by the embodiment of the present disclosure is significantly better than the solution obtained using the Hartley-Fock method as a classical chemical calculation method. Therefore, the method provided by the embodiment of the present disclosure can enhance the accuracy of classical computational chemistry methods with the assistance of Bose sampling linear interferometer.

[0104] According to another aspect of the present disclosure, a method for predicting the chemical reaction rate of a target molecule using the target wave function obtained by the above method is provided.

[0105] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A method for determining electronic structure based on Bose sampling, comprising: Using a linear optical interferometer to generate a current wave function corresponding to a target molecule, wherein the current wave function represents a wave function of the target molecule generated by the linear optical interferometer under a current phase parameter; Determining a current Hamiltonian corresponding to the target molecule using a preset target chemical calculation method, wherein the current Hamiltonian represents the Hamiltonian of the target molecule generated by the target chemical calculation method under current calculation parameters; Determining a current energy value using the current wave function and the current Hamiltonian, wherein the current energy value represents an energy value corresponding to the current Hamiltonian under the current wave function; updating the current phase parameters of the linear optical interferometer and the current calculation parameters of the target chemical calculation method using a preset optimization method based on the current energy value to obtain updated phase parameters of the linear optical interferometer and updated calculation parameters of the target chemical calculation method; and The above operation is iteratively performed until the current energy value satisfies a preset iteration condition, and when the preset iteration condition is satisfied, the wave function generated by the linear optical interferometer is used as the target wave function of the target molecule, wherein the target wave function is used to determine the electronic structure of the target molecule.

2. The method according to claim 1, further comprising: determining an initial Hamiltonian and an initial reference state corresponding to the target molecule according to the electronic structure of the target molecule; The step of generating a current wave function corresponding to the target molecule by using a linear optical interferometer includes: Updating the initial reference state using the linear optical interferometer to obtain the current wave function; Determining the current Hamiltonian corresponding to the target molecule by using a preset target chemical calculation method includes: The initial Hamiltonian is transformed using the target chemical calculation method to obtain the current Hamiltonian.

3. The method according to claim 2, wherein: The updating the initial reference state by using the linear optical interferometer to obtain the current wave function includes: determining initial light source input information of the linear optical interferometer according to the initial reference state; A single photon source is input into the linear optical interferometer according to the initial light source input information, and the current wave function is output.

4. The method according to claim 1, wherein Determining a current energy value using the current wave function and the current Hamiltonian includes: Measuring information of the current wave function using a homodyne measurement method; The current energy value is determined according to the information of the current wave function and the Hamiltonian.

5. The method according to claim 1, further comprising: Before generating the current wave function corresponding to the target molecule using the linear optical interferometer, randomly generating a set of phase parameters to obtain initial phase parameters; The initial phase parameter is used as the current phase parameter of the linear optical interferometer.

6. The method according to claim 1, further comprising: Before determining the current Hamiltonian corresponding to the target molecule using a preset target chemical calculation method, randomly generating a set of calculation parameters to obtain initial calculation parameters; The initial calculation parameters are used as current calculation parameters of the target chemical calculation method.

7. The method according to claim 1, wherein The phase parameter of the linear optical interferometer includes at least one of the following: wave plate angle, wave plate position, and transmittance.

8. The method according to claim 1, wherein The preset optimization method includes: gradient descent method, particle swarm swimming method or second-order quasi-Newton method.

9. The method according to claim 1, wherein The target chemical calculation method includes: Hartley-Fock method, coupled cluster or density functional theory.

10. A method for predicting the chemical reaction rate of a target molecule using a target wave function obtained by the method according to any one of claims 1 to 9.

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