Molecular dynamics simulation method and device based on quantum computing

Abstract

The invention discloses a molecular dynamics simulation method and device based on quantum computing, and the method comprises the steps: preparing a first quantum state with an atomic nucleus represented as a wave packet, and determining evolution time which comprises a plurality of evolution stages; according to the first quantum state, multiple pieces of evolution processing corresponding to multiple evolution stages are sequentially executed to obtain an evolved second quantum state, the multiple evolution stages comprise the evolution stage, and the execution of the evolution processing corresponding to the evolution stage comprises the steps that before the evolution stage, a third quantum state of the atomic nucleus before the evolution stage is measured for multiple times, and the evolved second quantum state is obtained; obtaining a plurality of target positions of the atomic nucleus, determining a plurality of potential energy values corresponding to the plurality of target positions according to the plurality of target positions, and constructing a plurality of first quantum gates corresponding to the plurality of potential energy values; determining a second quantum gate according to the kinetic energy of the atomic nucleus; and obtaining a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gates.

Description

Technical Field

[0001] The present invention relates to the field of quantum chemistry, and in particular to a molecular dynamics simulation method and device based on quantum computing. Background Art

[0002] Molecular dynamics simulation is an important computational chemistry method used to study the structure, dynamic behavior and interaction of molecules under different conditions. By simulating the movement and interaction of molecules, we can gain a deeper understanding of the mechanism of chemical reactions, the structure and function of biomolecules, and the properties of materials. This method has a wide range of applications in drug design, materials science, biophysics and other fields. However, traditional molecular dynamics simulations often face challenges of high computational complexity and long time consumption when dealing with large-scale molecular systems. Especially when simulating macromolecular systems or dynamic processes on long time scales, traditional classical computational methods may encounter problems such as insufficient computing resources and insufficient accuracy.

[0003] Therefore, a molecular dynamics simulation method and device based on quantum computing are needed. Summary of the invention

[0004] The purpose of the present invention is to provide a molecular dynamics simulation method and device based on quantum computing. By combining the classical description and quantum description of the atomic nucleus, a new molecular dynamics quantum computing simulation method that regards the atomic nucleus as a wave packet is proposed. Based on this method, the quantum effect of the atomic nucleus is taken into account while reducing the computational complexity, and the depth of the quantum circuit and the requirements for quantum hardware are also reduced, saving the resources of quantum devices.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a molecular dynamics simulation method based on quantum computing, comprising:

[0006] preparing a first quantum state of a target atomic nucleus represented as a wave packet, and determining a target evolution time, wherein the target evolution time includes a plurality of evolution stages;

[0007] According to the first quantum state, a plurality of evolutionary processes corresponding to a plurality of evolutionary stages are sequentially performed to obtain an evolved second quantum state, wherein the plurality of evolutionary stages include a target evolutionary stage, and performing the evolutionary process corresponding to the target evolutionary stage includes:

[0008] Before the target evolution stage, the third quantum state of the target atomic nucleus before the target evolution stage is measured multiple times to obtain multiple target positions of the atomic nucleus, and multiple potential energy values ​​corresponding to the multiple target positions are determined according to the multiple target positions and presets; multiple first quantum gates corresponding to the multiple potential energy values ​​are constructed, and the second quantum gate is determined according to the kinetic energy of the target atomic nucleus;

[0009] A fourth quantum state is obtained according to the third quantum state, the plurality of first quantum gates and the second quantum gate.

[0010] Specifically, determining a plurality of potential energy values ​​corresponding to the plurality of target positions according to the plurality of target positions includes: determining a plurality of potential energy values ​​corresponding to the plurality of target positions by a variational quantum eigenvalue solver according to the plurality of target positions.

[0011] Specifically, the wave packet includes a wave function corresponding to a predetermined position.

[0012] Preferably, the multiple first quantum gates corresponding to the multiple potential energy values ​​are expressed as: ,in, is the projection operator, K is the serial number of the first quantum gate, is the time interval, is the potential energy value, is an imaginary unit, is a natural constant.

[0013] Specifically, the second quantum gate is expressed as ,in, is an imaginary unit, is a natural constant, is the time interval, is the nuclear kinetic energy operator.

[0014] Specifically, obtaining the fourth quantum state according to the third quantum state, the multiple first quantum gates and the second quantum gate includes: sequentially applying the second quantum gate and the multiple first quantum gates to the third quantum state to obtain the fourth quantum state.

[0015] In a second aspect, the present invention provides a molecular dynamics simulation device based on quantum computing, comprising:

[0016] a determination unit configured to prepare a first quantum state of a target atomic nucleus represented as a wave packet, and to determine a target evolution time, wherein the target evolution time includes a plurality of evolution stages;

[0017] The processing unit is configured to, according to the first quantum state, sequentially perform multiple evolutionary processes corresponding to multiple evolutionary stages to obtain an evolved second quantum state, wherein the multiple evolutionary stages include a target evolutionary stage, and performing the evolutionary process corresponding to the target evolutionary stage includes:

[0018] Before the target evolution stage, the third quantum state of the target atomic nucleus before the target evolution stage is measured multiple times to obtain multiple target positions of the atomic nucleus, and multiple potential energy values ​​corresponding to the multiple target positions are determined according to the multiple target positions; multiple first quantum gates corresponding to the multiple potential energy values ​​are constructed, and a second quantum gate is determined according to the kinetic energy of the target atomic nucleus;

[0019] The output unit is configured to obtain a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gate.

[0020] In a third aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed on an electronic device, enables the electronic device to execute the method described in the first aspect.

[0021] In a fourth aspect, the present invention provides an electronic device comprising: a processor, a memory, and computer program instructions stored in the memory and executable on the processor, wherein the processor is used to implement the method described in the first aspect when executing the computer program instructions.

[0022] Compared with the prior art, the present invention has the following advantages: considering the nuclear wave function as a wave packet can effectively reduce the computational complexity, is easier to implement on the existing quantum computing platform, retains certain quantum properties, and can handle more complex molecular structures and larger system scales. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a molecular dynamics simulation method based on quantum computing provided by an embodiment of the present invention; Figure 2 A quantum circuit diagram of a molecular dynamics simulation method based on quantum computing provided by an embodiment of the present invention; Figure 3 A structural diagram of a molecular dynamics simulation device based on quantum computing provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0026] In the description of the embodiments of the present invention, words such as "exemplary", "for example" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a concrete way.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. The terms "include", "comprises", "has" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0028] One of the goals of molecular dynamics simulation is to describe and understand the motion trajectories of atomic nuclei within molecules and their interactions, so as to infer the structure, properties and behavior of molecules. In molecular dynamics simulation, the motion trajectories of atomic nuclei evolve under a given potential energy surface (usually determined by the molecular structure and electronic state). Therefore, one of the keys to molecular dynamics simulation is to accurately describe the motion of atomic nuclei in a given potential energy field.

[0029] In traditional molecular dynamics simulation, a semiclassical method is used, which combines classical mechanics and quantum mechanics. In this method, the motion of the nucleus evolves according to the classical force field, while the electronic structure is described by quantum mechanics. The specific process is as follows: First, the Born-Oppenheimer approximation is used to regard the nucleus as stationary, and the Hamiltonian of the electron is obtained. The electron orbit is solved based on the electronic Hamiltonian to obtain the density distribution of all electrons in the molecule. The electron density distribution is then used to approximate the interaction between the electron and the nucleus, that is, the equivalent potential energy surface of the nucleus. Finally, the nucleus is regarded as a classical particle, and its motion in the potential energy surface is solved based on the Newton equation.

[0030] Although the semiclassical method separates the interaction between the nucleus and the electron, achieving a balance between computational efficiency and accuracy, its essence is still to describe the motion of the nucleus with a classical force field. Therefore, the semiclassical method cannot accurately simulate the quantum effects of the nucleus, such as zero-point vibrations, quantum fluctuations and other phenomena. In some cases, especially in low temperature or high energy environments, the quantum effects of the nucleus may have an important impact on the molecular dynamics process, and the semiclassical method cannot capture these effects, resulting in inaccurate simulation results. In addition, the classical force field in the semiclassical method is usually obtained based on empirical parameter fitting, and its accuracy and scope of application are limited by parameter selection. Due to the different structures and properties of different molecular systems, it is often necessary to optimize or adjust parameters for specific systems, which increases the uncertainty in the simulation process and limits the versatility and scope of application of the method.

[0031] With the development of quantum computing technology, more and more studies have begun to use quantum mechanics to simulate molecular dynamics processes. In the quantum mechanics method, both the nucleus and the electron are regarded as wave functions, and their evolution is described by the Schrödinger equation. Due to the wave-particle duality of quantum mechanics, the quantum mechanics method can more accurately describe the quantum behavior of the nucleus, including the coherence of the wave function, quantum tunneling and other effects. The specific process is as follows: the overall quantum state of the nucleus and the electron at the initial moment is given. According to the overall Hamiltonian, the state of the initial overall quantum state after time t is simulated. The electronic part of the overall quantum state is traced to obtain the final quantum state of the nucleus.

[0032] Although quantum mechanics methods can provide higher accuracy and reliability due to the consideration of the complete quantum effects of the nucleus and electrons, the computational complexity is usually high, especially when dealing with large-scale molecular systems. Since it is usually impossible to obtain an accurate expression for the equivalent potential energy surface of the nucleus, it acts as a black box and can only obtain the potential energy value at a certain spatial coordinate each time it is accessed. Accurate simulation of the quantum mechanical behavior of the nucleus usually requires the potential energy values ​​of exponentially multiple spatial coordinates. Therefore, in practical applications, quantum mechanics methods often require a large amount of computing resources and time, which limits their application in the simulation of large-scale molecular systems.

[0033] In order to overcome the shortcomings of the existing technology, a molecular dynamics simulation method based on quantum computing is proposed. By performing multiple sampling measurements on the current quantum state of the atomic nucleus, the wave function wave packet position is approximately obtained. Only the value of the potential energy surface at the above position is calculated, and the potential energy at other positions outside the wave packet is ignored, and a potential energy approximate function that can be obtained by polynomial calculations can be obtained; this approximate potential energy can simulate strict evolution at the position where the atomic nucleus mainly appears, so a high accuracy can still be obtained, and the quantum mechanical representation of the atomic nucleus is still retained, and its quantum effect can be simulated.

[0034] Figure 1 A flow chart of a molecular dynamics simulation method based on quantum computing provided by an embodiment of the present invention. Figure 1 As shown, the method comprises at least the following steps:

[0035] S101: preparing a first quantum state of a wave packet represented by a target atomic nucleus, and determining a target evolution time, wherein the target evolution time includes a plurality of evolution stages.

[0036] A wave packet refers to a wave formed by the superposition of simple harmonic waves of different frequencies and wave numbers (or wavelengths). In space, a wave packet is usually not infinitely extended like a simple harmonic wave, but has a significant amplitude in a certain spatial region. Outside this region, the amplitude can decay rapidly and approach zero, as if the wave is "wrapped" in a limited spatial range, so it is called a wave packet. In one embodiment, the wave packet includes a wave function corresponding to a predetermined position.

[0037] For example, the state of the nucleus at the initial moment is selected. This state presents a wave packet form, that is, it is mainly concentrated at a certain point. For example, it can be selected as a wave function at a predetermined specific position. And set the target evolution time T and the time interval Δt. According to the selected target evolution time T and the time interval Δt, the total number of evolution steps n=T / Δt can be calculated. In different specific examples, the wave function of the predetermined position can be the wave function of different specific positions, and this specification does not limit this.

[0038] S102: According to the first quantum state, sequentially perform multiple evolutionary processes corresponding to multiple evolutionary stages to obtain an evolved second quantum state, wherein the multiple evolutionary stages include a target evolutionary stage, and performing the evolutionary processes corresponding to the target evolutionary stage includes:

[0039] Before the target evolution stage, the third quantum state of the target atomic nucleus before the target evolution stage is measured multiple times to obtain multiple target positions of the atomic nucleus, and multiple potential energy values ​​corresponding to the multiple target positions are determined according to the multiple target positions and a preset potential energy determination module; multiple first quantum gates corresponding to the multiple potential energy values ​​are constructed, and the second quantum gate is determined according to the kinetic energy of the target atomic nucleus.

[0040] In different embodiments, the specific manner of determining the corresponding potential energy value according to the target position may be different. In a specific embodiment, a variational quantum eigenvalue solver may be used to determine multiple potential energy values ​​corresponding to the nucleus at multiple positions.

[0041] In one embodiment, the multiple first quantum gates corresponding to the multiple potential energy values ​​can be expressed as: ,in, is the projection operator, K is the serial number of the first quantum gate, is the time interval, is the potential energy value, is an imaginary unit, is a natural constant.

[0042] In one embodiment, the second quantum gate can be expressed as ,in, is an imaginary unit, is a natural constant, is the time interval, is the nuclear kinetic energy operator.

[0043] In one embodiment, obtaining a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gate comprises: applying the second quantum gate to the third quantum state, and then applying the plurality of first quantum gates in sequence to obtain the fourth quantum state.

[0044] For example, starting from the initial moment, before the start of each short time interval, the quantum state of the nucleus is measured and sampled multiple times to obtain the possible positions of several nuclei. For each sampled position, a module for calculating the potential energy surface is called. This module can represent a computational model. For example, the Hartree-Fock (HF) method or coupled-cluster singles and doubles (Coupled-Cluster Singles and Doubles) method can be implemented on a quantum computer through a variational quantum eigensolver (VQE). The potential energy values ​​at these positions are obtained by inputting the atomic nucleus position information into the module. , and construct the corresponding gate in the quantum circuit ,in, is the projection operator, K is the serial number of the first quantum gate, is the time interval, is the potential energy value, is an imaginary unit, is a natural constant. Figure 2 A quantum circuit diagram of a molecular dynamics simulation method based on quantum computing provided by an embodiment of the present invention, such as Figure 2 As shown, the state of the nucleus is represented by the wave function Description, this is the starting point of the whole process, this wave function contains the atomic nucleus at a specific time All information; According to the kinetic energy of the target nucleus, the second quantum gate is determined, where the second quantum gate can be expressed as ,in, is an imaginary unit, is a natural constant, is the time interval, is the nuclear kinetic energy operator, and multiple first quantum gates are ,in, is the projection operator, K is the serial number of the first quantum gate, is the time interval, is the potential energy value, is an imaginary unit, is a natural constant.

[0045] S103: Obtain a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gate.

[0046] For example, the Schrödinger equation is used to describe the time evolution, and the wave function is evolved through quantum circuits to obtain the next moment The quantum state of the nucleus This new quantum state can be used as the initial state for the next round of simulation. By repeating this process, the evolution of the nuclear quantum state over time can be simulated.

[0047] According to yet another embodiment, a molecular dynamics simulation device based on quantum computing is provided. Figure 3 A structural diagram of a molecular dynamics simulation device based on quantum computing provided by an embodiment of the present invention, such as Figure 3 As shown, the device 300 includes:

[0048] The determination unit 301 is configured to prepare a first quantum state of a target atomic nucleus represented as a wave packet, and determine a target evolution time, wherein the target evolution time includes a plurality of evolution stages;

[0049] The processing unit 302 is configured to, according to the first quantum state, sequentially perform multiple evolutionary processes corresponding to multiple evolutionary stages to obtain an evolved second quantum state, wherein the multiple evolutionary stages include a target evolutionary stage, and performing the evolutionary process corresponding to the target evolutionary stage includes:

[0050] Before the target evolution stage, the third quantum state of the target atomic nucleus before the target evolution stage is measured multiple times to obtain multiple target positions of the atomic nucleus, and multiple potential energy values ​​corresponding to the multiple target positions are determined according to the multiple target positions; multiple first quantum gates corresponding to the multiple potential energy values ​​are constructed, and a second quantum gate is determined according to the kinetic energy of the target atomic nucleus;

[0051] The output unit 303 is configured to obtain a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gate.

[0052] It is understandable that the method steps in the embodiments of the present invention can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0053] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A molecular dynamics simulation method based on quantum computing, comprising: preparing a first quantum state of a target atomic nucleus represented as a wave packet, and determining a target evolution time, wherein the target evolution time includes a plurality of evolution stages; According to the first quantum state, a plurality of evolutionary processes corresponding to a plurality of evolutionary stages are sequentially performed to obtain an evolved second quantum state, wherein the plurality of evolutionary stages include a target evolutionary stage, and performing the evolutionary process corresponding to the target evolutionary stage includes: Before the target evolution stage, the third quantum state of the target atomic nucleus before the target evolution stage is measured multiple times to obtain multiple target positions of the atomic nucleus, and multiple potential energy values ​​corresponding to the multiple target positions are determined according to the multiple target positions; multiple first quantum gates corresponding to the multiple potential energy values ​​are constructed, and a second quantum gate is determined according to the kinetic energy of the target atomic nucleus; A fourth quantum state is obtained according to the third quantum state, the plurality of first quantum gates and the second quantum gate.

2. The method according to claim 1, wherein: Determining multiple potential energy values ​​corresponding to the multiple target positions according to the multiple target positions includes: determining multiple potential energy values ​​corresponding to the multiple target positions by a variational quantum eigenvalue solver according to the multiple target positions.

3. The method according to claim 1, wherein: The wave packet includes a wave function corresponding to a predetermined position.

4. The method according to claim 1, wherein: The multiple first quantum gates corresponding to the multiple potential energy values ​​are expressed as: ,in, is the projection operator, K is the serial number of the first quantum gate, is the time interval, is the potential energy value, is an imaginary unit, is a natural constant.

5. The method according to claim 1, wherein: The second quantum gate is expressed as ,in, is an imaginary unit, is a natural constant, is the time interval, is the nuclear kinetic energy operator.

6. The method according to claim 1, wherein obtaining a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gate comprises: The second quantum gate and the plurality of first quantum gates are sequentially applied to the third quantum state to obtain a fourth quantum state.

7. A molecular dynamics simulation device based on quantum computing, comprising: a determination unit configured to prepare a first quantum state of a target atomic nucleus represented as a wave packet, and to determine a target evolution time, wherein the target evolution time includes a plurality of evolution stages; The processing unit is configured to, according to the first quantum state, sequentially perform multiple evolutionary processes corresponding to multiple evolutionary stages to obtain an evolved second quantum state, wherein the multiple evolutionary stages include a target evolutionary stage, and performing the evolutionary process corresponding to the target evolutionary stage includes: Before the target evolution stage, the third quantum state of the target atomic nucleus before the target evolution stage is measured multiple times to obtain multiple target positions of the atomic nucleus, and multiple potential energy values ​​corresponding to the multiple target positions are determined according to the multiple target positions, and multiple first quantum gates corresponding to the multiple potential energy values ​​are constructed; and the second quantum gate is determined according to the kinetic energy of the target atomic nucleus; The output unit is configured to obtain a fourth quantum state according to the third quantum state, the plurality of first quantum gates and the second quantum gate.

8. A computer-readable storage medium storing a computer program, wherein when the computer program is executed on an electronic device, the electronic device executes the method according to any one of claims 1 to 6.

9. An electronic device, comprising: A processor, a memory, and computer program instructions stored in the memory and running on the processor, wherein the processor is used to implement the method according to any one of claims 1 to 6 when executing the computer program instructions.

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