A method for constructing a quantum state, a quantum computer device, and a storage medium

Abstract

The present invention provides a method for constructing a quantum state, a quantum computer device, and a storage medium. By analyzing the energy levels of zero-dimensional, one-dimensional, and two-dimensional carbon nanomaterials and carbon nanomaterial models with different combinations of additional numbers of electrons, and using the Fermi distribution formula, we systematically analyze how the electron occupation probability of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) varies with temperature. Under a specific amount of applied charge, the combined occupation probability of the HOMO and LUMO remains constant at 1, which can be regarded as a quantum bit. The quantum state can also be precisely controlled by temperature regulation, providing a new foundation for the construction of quantum states in quantum computers and solving the problem of the difficulty of constructing quantum states.

Description

Technical Field

[0001] The present invention relates to the field of quantum computer technology, and in particular to a method for constructing a quantum state, a quantum computer device, and a storage medium. Background Art

[0002] Quantum computers are a new type of information processing system based on the principles of quantum mechanics. Due to their inherent parallelism, these systems have the ability to solve problems that are intractable for classical computers. For example, the Rivest-Shamir-Adleman (RSA) algorithm, the core of current public-key cryptography, becomes exponentially more difficult for classical computers as the length of the numbers increases. In contrast, quantum computers can efficiently factor such large numbers in a fraction of a second using Shor's algorithm.

[0003] Quantum superposition is a cornerstone of quantum information theory, enabling qubits to represent not only the classical states 0 and 1, but also any intermediate state. Classical bits are limited to either 0 or 1. In the quantum realm, qubits can exist simultaneously in a superposition of |0> and |1>, or any other combination of these states. While classical information processing is deterministic and relies on binary digits (bits), quantum information processing is probabilistic and utilizes qubits that can exist in any superposition of 0 and 1.

[0004] The key challenge in the current development of quantum computing lies in finding a stable and scalable physical implementation system. Existing qubit solutions include spin qubits, photon qubits, defect qubits, and superconducting qubits, but they still face bottlenecks such as decoherence and manipulation accuracy. Summary of the Invention

[0005] The present invention provides a quantum state construction method, a quantum computer device and a storage medium to achieve the effect of obtaining a quantum state in a carbon nano-atom model.

[0006] Carbon nanomaterials exhibit unique energy levels and spin distributions when subjected to different external charges. In particular, for certain quantum dots, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) exhibit unique spin configurations, such as spin-up only or a combination of spin-down and spin-up. Notably, under certain conditions, the sum of the electron occupancy numbers of the HOMO and LUMO is always 1, and the occupation probability of these orbitals can be tuned by temperature.

[0007] In one aspect, the method for constructing a quantum state in the present invention comprises the following steps:

[0008] S1. Build atomic models of carbon nanomaterials containing different extra electrons;

[0009] S2. Perform first-principles calculations based on density functional theory and analyze the electron occupation probabilities of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the atomic model according to the energy level formula;

[0010] S3, adjusting the temperature of the environment where the atomic model is located, and determining an effective carbon nanomaterial atomic model in which the HOMO and LUMO electron occupation probabilities are always 1 under temperature changes;

[0011] S4. Based on the atomic model of the effective carbon nanomaterial, the occupied state of its electrons is a superposition state of HOMO and LUMO. The sum of the probabilities of these occupied states remains unchanged at 1 and is regarded as a quantum bit to construct a quantum state.

[0012] Furthermore, the carbon nanomaterial atomic model is composed of zero-dimensional, one-dimensional, or two-dimensional carbon atoms and additional electrons.

[0013] Furthermore, the number of the additional electrons is 0-6.

[0014] Furthermore, the zero-dimensional carbon atom is C100 fullerene, C60 or C140 fullerene, the one-dimensional carbon atom is a carbon nanotube, and the two-dimensional carbon atom is a square graphene.

[0015] Furthermore, the first principles calculations were performed using the Vienna ab initio simulation package, using the projected augmented wave method, and the exchange correlation energy was treated using the Perdew-Burke-Ernzerhof functional based on the generalized gradient approximation, where the cutoff kinetic energy of the plane wave basis set was set to 400 eV and the convergence threshold energy was set to eV. The atomic positions were fully relaxed until the force exerted on each atom was less than 0.01 eV / Å. The supercell used in the calculation had a vacuum layer of at least 20 Å in all three dimensions to prevent interactions between adjacent carbon nanomaterials, so that only a single k-point was needed to represent the Brillouin zone. The spin-polarized and non-spin-polarized states of all models were calculated to determine their stability. The total energies were compared, and the lower energy state was selected as the ground state for subsequent analysis.

[0016] Furthermore, the energy level formula is the Fermi distribution formula for the electron occupation probability of a given energy level:

[0017] (1)

[0018] Where k is the Boltzmann constant, T is the temperature, and E F is the Fermi energy, E is the energy of the individual energy level, and f is the occupation probability of the energy level;

[0019] The electron occupation probabilities of HOMO and LUMO at different temperatures are calculated according to formula (1).

[0020] Furthermore, when considering the effect of temperature on energy levels, the energy level formula uses the Fermi energy correction formula for the electron occupation probability of a given energy level:

[0021] (2)

[0022] Where k is the Boltzmann constant, T is the temperature, is the original Fermi energy, E F Corrected Fermi energy.

[0023] The present invention also provides a quantum computer device, comprising one or more processors; a storage device for storing one or more computer programs; when the one or more computer programs are executed by the processor, the processor implements the quantum state construction method as described above.

[0024] The present invention also provides a computer-readable storage medium, which stores a computer program, characterized in that when the computer program is executed by a processor, it implements the above-mentioned method for constructing a quantum state.

[0025] The beneficial effects of the present invention are: based on first-principles calculations based on density functional theory (DFT) and using the Fermi level formula, it is obtained that under a specific combination of additional electrons, the carbon nanomaterial presents an energy level distribution in which the sum of the electron occupancy numbers of HOMO and LUMO is always 1, and the occupation probability of these orbitals can be adjusted by temperature, which reduces the complexity and difficulty of constructing quantum states in quantum computers and provides a new foundation for quantum computer calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic flow chart of a method for constructing a quantum state provided in Example 1 of the present invention;

[0027] Figure 2 The graph shows the variation of the electron occupation probability of HOMO+LUMO with temperature for one-dimensional carbon nanomaterials (composed of (5,5) carbon nanotubes) with 0-6 extra electrons;

[0028] Figure 3a This is a graph showing the variation of the electron occupation probability of HOMO+LUMO with temperature for a one-dimensional carbon nanomaterial (5,5) carbon nanotube with three extra electrons.

[0029] Figure 3b This is a graph showing the variation of the electron occupation probability of HOMO+LUMO with temperature for a one-dimensional carbon nanomaterial (5,5) carbon nanotube with one extra electron.

[0030] Figure 3cThis is a graph showing the variation of the electron occupation probability of HOMO+LUMO with temperature for a one-dimensional carbon nanomaterial (5,5) carbon nanotube with 6 extra electrons.

[0031] Figure 4 Figure 3 shows the temperature variations of HOMO, LUMO, and HOMO+LUMO of one-dimensional carbon nanomaterials (composed of (5,5) carbon nanotubes with 3 extra electrons) after Fermi energy correction.

[0032] Figure 5 Zero-dimensional carbon nanomaterial C 100 The electron occupation probability of HOMO+LUMO varies with temperature for fullerenes with 0-6 extra electrons.

[0033] Figure 6 The graph shows the variation of the electron occupation probability of HOMO+LUMO with temperature when the two-dimensional carbon nanomaterial graphene has 0-6 extra electrons;

[0034] Figure 7 A schematic diagram of the structure of a quantum computer device provided in Example 4 of the present invention; DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0036] Example 1

[0037] Figure 1 This is a flow chart of a quantum state determination method provided in Example 1 of the present invention. This embodiment is applicable to determining the quantum state after performing quantum computation in a quantum computing device. The method can be performed by a quantum state determination device, which can be implemented by software and / or hardware and integrated into a device with data processing capabilities, such as a laptop or desktop computer. The method specifically includes the following steps:

[0038] S1. Establish a one-dimensional carbon nanomaterial model consisting of a (5,5) carbon nanotube containing 100 carbon atoms and 0-6 additional electrons;

[0039] S2. First-principles calculations were performed based on density functional theory (DFT) to determine the electrical and spintronic properties of carbon nanotubes under different external charges. The electron occupation probabilities of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the atomic model were analyzed according to the Fermi level formula. In this step, the first-principles calculations were performed using the Vienna ab initio simulation package (VASP) using the projected augmented wave (PAW) method. The exchange correlation energy was processed using the Perdew-Burke-Ernzerhof (PBE) functional based on the generalized gradient approximation (GGA). The cutoff kinetic energy of the plane wave basis set was set to 400 eV, and the convergence threshold energy was set to eV. The atomic positions were fully relaxed until the force exerted on each atom was less than 0.01 eV / Å. The supercell used in the calculations had a vacuum layer of at least 20 Å in all three dimensions, which was large enough to prevent interactions between adjacent carbon nanomaterials and to represent the Brillouin zone with only a single k-point. This allowed calculations of both the spin-polarized and non-spin-polarized states of all models to ensure their stability.

[0040] Furthermore, the Fermi level formula used in this step is:

[0041] (1)

[0042] Where k is the Boltzmann constant, T is the temperature, and E F is the Fermi energy, E is the energy of the individual energy level, and f is the occupation probability of the energy level. Using this formula, we calculate the electron occupation probability of HOMO and LUMO of the established carbon nanotube carbon atom model at different temperatures, as follows Figure 2 shown.

[0043] At this time, according to the Fermi level formula, the electron occupation probabilities of HOMO and LUMO at different temperatures for C100 carbon nanotubes with 1, 3, and 6 extra electrons are obtained as follows: Figure 3a-3c shown.

[0044] When taking into account the possible influence of temperature, the energy level formula adopts the Fermi energy correction formula:

[0045] (2)

[0046] Where k is the Boltzmann constant, T is the temperature, is the original Fermi energy, E F Corrected Fermi energy.

[0047] Under the Fermi energy correction formula (2), the electron occupation probability of HOMO and LUMO at different temperatures is obtained, as shown in Figure 4 shown.

[0048] S3, adjusting the temperature of the environment where the atomic model is located, and determining an effective carbon nanomaterial atomic model in which the HOMO and LUMO electron occupation probabilities are always 1 under temperature changes;

[0049] In this embodiment, the effective carbon nanomaterial atomic model is a (5,5) carbon nanotube with 3 extra electrons; the electron occupation probabilities of its HOMO, LUMO and HOMO+LUMO as a function of temperature are as follows: Figure 3a As shown, the sum of HOMO+LUMO under the Fermi level formula is always 1; under the Fermi energy correction formula (2), as Figure 4 In the room temperature range (300K-500K), the influence of the Fermi level on the occupation probability of HOMO and LUMO is negligible.

[0050] S4. Based on the above-mentioned atomic model of effective carbon nanomaterials, the occupied state of its electrons is a superposition of HOMO and LUMO. The sum of the probabilities of these occupied states remains unchanged at 1 and is regarded as a quantum bit to construct the quantum state.

[0051] Example 2

[0052] On the basis of Example 1, in step S1 of the method for constructing the quantum state, the atomic model of the carbon nanomaterial is selected as a zero-dimensional carbon atom, that is, the carbon atom of C100 fullerene as the basis, with 0-6 additional electrons, and the electron occupation probability of its HOMO, LUMO and HOMO+LUMO changes with temperature is as follows: Figure 5 shown.

[0053] In this embodiment, the effective carbon nanomaterial atomic model is a model of C100 fullerene with 4 and 6 extra electrons, and the sum of HOMO+LUMO is always 1.

[0054] Example 3

[0055] On the basis of Example 1, in step S1 of the method for constructing the quantum state, the carbon nanomaterial atomic model is selected as a two-dimensional nanomaterial composed of square graphene, which contains nearly 100 carbon atoms, and the electron occupation probabilities of its HOMO, LUMO and HOMO+LUMO changing with temperature are as follows: Figure 6 As shown;

[0056] In this embodiment, the effective carbon nanomaterial atomic model is a model in which the two-dimensional nanomaterial has 4 and 6 extra electrons, and the sum of HOMO+LUMO is always 1.

[0057] Example 4

[0058] A schematic structural diagram of a quantum computer device provided in Example 4 of the present invention. Figure 7A block diagram of an exemplary quantum computer device 12 suitable for use in implementing embodiments of the present invention is shown. Figure 7 The quantum computer device 12 shown is only an example and should not limit the functions and scope of use of the embodiments of the present invention.

[0059] like Figure 7 As shown, the quantum computer device 12 is implemented as a universal quantum computer device. Components of the quantum computer device 12 may include, but are not limited to, one or more processors 16, a storage device 28, and a bus 18 connecting various system components (including the storage device 28 and the processor 16).

[0060] Bus 18 represents one or more of several types of bus structures, including a storage device bus or storage device controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures. Examples of these architectures include, but are not limited to, an Industry Standard Architecture bus, a Micro Channel Architecture bus, an Enhanced ISA bus, a Video Electronics Standards Association local bus, and a Peripheral Component Interconnect bus.

[0061] The quantum computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the quantum computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0062] The storage device 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The terminal 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be configured to read and write non-removable, non-volatile magnetic media ( Figure 7 Not shown, often called a "hard drive"). Although Figure 7 Although not shown, a magnetic disk drive for reading and writing to a removable non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing to a removable non-volatile optical disk, such as a read-only compact disk (CD-ROM), a digital video disk (DVD-ROM), or other optical media, may be provided. In these cases, each drive may be connected to bus 18 via one or more data media interfaces. Storage device 28 may include at least one computer program product having a set (e.g., at least one) of computer program modules configured to perform the functions of various embodiments of the present invention.

[0063] A computer program / utility 40 having a set (at least one) of computer program modules 42 may be stored, for example, in storage device 28. Such computer program modules 42 include, but are not limited to, an operating system, one or more application computer programs, other computer program modules, and computer program data, each of which, or some combination thereof, may include an implementation of a network environment. Computer program modules 42 generally perform the functions and / or methods of the embodiments described herein.

[0064] The quantum computer device 12 may also communicate with one or more external devices 14 (e.g., a keyboard, a pointing terminal, a display 24, etc.), one or more terminals that enable a user to interact with the quantum computer device 12, and / or any terminal that enables the quantum computer device 12 to communicate with one or more other computing terminals (e.g., a network card, a modem, etc.). Such communication may be performed through an input / output (I / O) interface 22. Furthermore, the quantum computer device 12 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 20. Figure 7 As shown, the network adapter 20 communicates with other modules of the quantum computer device 12 via the bus 18. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the quantum computer device 12, including but not limited to: microcode, terminal drivers, redundant processors, external disk drive arrays, disk array (RAID) systems, tape drives, and data backup storage systems.

[0065] The processor 16 executes various functional applications and data processing by running the computer program stored in the storage device 28, such as implementing a quantum state construction method provided in any embodiment of the present invention, which includes:

[0066] S1. Establish and obtain atomic models of different carbon nanomaterials;

[0067] S2. Perform first-principles calculations based on density functional theory and analyze the electron occupation probabilities of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the atomic model according to the energy level formula;

[0068] S3, adjusting the temperature of the environment where the atomic model is located, and determining an effective carbon nanomaterial atomic model in which the HOMO and LUMO electron occupation probabilities are always 1 under temperature changes;

[0069] S4. Based on the atomic model of the effective carbon nanomaterial, the occupied state of its electrons is a superposition state of HOMO and LUMO. The sum of the probabilities of these occupied states remains unchanged at 1 and is regarded as a quantum bit to construct a quantum state.

[0070] Example 5

[0071] Embodiment 5 of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for constructing a quantum state as provided in any embodiment of the present invention is implemented, the method comprising:

[0072] S1. Establish and obtain atomic models of different carbon nanomaterials;

[0073] S2. Perform first-principles calculations based on density functional theory and analyze the electron occupation probabilities of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the atomic model according to the energy level formula;

[0074] S3, adjusting the temperature of the environment where the atomic model is located, and determining an effective carbon nanomaterial atomic model in which the HOMO and LUMO electron occupation probabilities are always 1 under temperature changes;

[0075] S4. Based on the atomic model of the effective carbon nanomaterial, the occupied state of its electrons is a superposition state of HOMO and LUMO. The sum of the probabilities of these occupied states remains unchanged at 1 and is regarded as a quantum bit to construct a quantum state.

[0076] The above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for constructing a quantum state, characterized in that: Applied to a quantum computer, the method comprises the following steps: S1. Establish and obtain atomic models of different carbon nanomaterials; S2. Perform first-principles calculations based on density functional theory and analyze the electron occupation probabilities of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the atomic model according to the energy level formula; S3, adjusting the temperature of the environment where the atomic model is located, and determining an effective carbon nanomaterial atomic model in which the HOMO and LUMO electron occupation probabilities are always 1 under temperature changes; S4. Based on the atomic model of the effective carbon nanomaterial, the occupied state of its electrons is a superposition state of HOMO and LUMO. The sum of the probabilities of these occupied states remains unchanged at 1 and is regarded as a quantum bit to construct a quantum state.

2. The construction method according to claim 1, wherein: The carbon nanomaterial atomic model is composed of zero-dimensional, one-dimensional, or two-dimensional carbon atoms and additional electrons.

3. The construction method according to claim 2, wherein: The number of the additional electrons is 0-6.

4. The construction method according to claim 2, wherein: Zero-dimensional carbon atoms are C100 fullerene, C60 or C140 fullerene, one-dimensional carbon atoms are carbon nanotubes, and two-dimensional carbon atoms are square graphene.

5. The construction method according to claim 1, wherein: The first-principles calculations were performed using the Vienna ab initio simulation package, employing the projected augmented wave method. The exchange-correlation energy was treated using the Perdew-Burke-Ernzerhof functional based on the generalized gradient approximation. The kinetic energy cutoff of the plane wave basis set was set to 400 eV, and the convergence threshold energy was set to 10 -5 eV; the atomic positions were fully relaxed until the force exerted on each atom was less than 0.01 eV / Å; the supercell used in the calculation had a vacuum layer of at least 20 Å in all three dimensions to prevent interactions between adjacent carbon nanomaterials, so that only a single k-point was needed to represent the Brillouin zone; the spin-polarized and non-spin-polarized states of all models were calculated to determine their stability; the total energies were compared, and the lower-energy state was selected as the ground state for subsequent analysis.

6. The construction method according to claim 4, wherein: The energy level formula is the Fermi distribution formula for the electron occupation probability of a given energy level: （1） Among them, k B is the Boltzmann constant, T is the temperature, E F is the Fermi energy, E is the energy of the individual energy level, and f is the occupation probability of the energy level; The electron occupation probabilities of HOMO and LUMO at different temperatures are calculated according to formula (1).

7. The construction method according to claim 4, wherein: When the energy levels remain constant with temperature, the energy level formula uses the Fermi energy correction formula for the probability of electron occupation at a given energy level: （2） Among them, k B is the Boltzmann constant, T is the temperature, is the original Fermi energy, E F is the corrected Fermi energy.

8. A quantum computer device, characterized in that: One or more processors; a storage device for storing one or more computer programs; when the one or more computer programs are executed by the processor, the processor implements the method for constructing a quantum state as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for constructing a quantum state according to any one of claims 1 to 7 is implemented.

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