Single photon source generation method and related equipment

Abstract

The invention provides a single photon source generation method and related equipment, and belongs to the technical field of quantum bits. Obtaining a photon second-order correlation function corresponding to magnetic flux quantum bits in the target single photon source generation device to obtain a target second-order correlation function; wherein the target single-photon source generating device is a single-photon source generating device which is built by using magnetic flux quantum bits in advance; and based on the principle that the numerical value corresponding to the target second-order correlation function is less than 1, applying a driving signal with a specified amplitude and a specified frequency to magnetic flux quantum bits in the target single-photon source generation device, so that the target single-photon source generation device generates a single-photon source. Through the method, the performance of the single photon source can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum bit technology, and in particular to a method for generating a single photon source and related equipment. Background Art

[0002] A single-photon source (SPSS) is a quantum light source that can generate single photons on demand. It holds significant application value in quantum information science. Related technologies typically utilize a transmon qubit coupled to a superconducting cavity to generate SPS. However, due to the low anharmonicity of the energy levels of transmon qubits, quantum state leakage can easily occur, compromising the performance of SPSs and negatively impacting quantum computing and quantum information processing. Currently, there is no effective solution to this technical issue. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a method for generating a single photon source and related equipment to solve the technical problem in the related art that the method for generating a single photon source easily causes quantum state leakage and affects the performance of the single photon source.

[0004] In order to solve the above technical problems, the present invention provides a method for generating a single photon source, comprising:

[0005] When a single photon source is to be generated;

[0006] Obtaining a photon second-order correlation function corresponding to a magnetic flux qubit in a target single-photon source generating device to obtain a target second-order correlation function; wherein the target single-photon source generating device is a single-photon source generating device pre-built using the magnetic flux qubit;

[0007] Based on the principle that the numerical value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and a specified frequency is applied to the flux quantum bit in the target single-photon source generating device, so that the target single-photon source generating device generates the single-photon source.

[0008] In a specific embodiment of the present application, the target single-photon source generating device includes:

[0009] the flux qubit;

[0010] A control line for regulating the quantum state of the flux qubit;

[0011] An emission line superconducting cavity is used to emit the single photon source generated by the flux quantum bit.

[0012] In a specific embodiment of the present application, the control line is coupled to a middle position of the flux qubit.

[0013] In a specific embodiment of the present application, the expression of the target second-order correlation function is:

[0014] ;

[0015] Where, is the target second-order correlation function, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the first excited state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 2.

[0016] In a specific embodiment of the present application, based on the principle that the value corresponding to the target second-order correlation function is less than 1, applying a driving signal of a specified amplitude and a specified frequency to the magnetic flux qubit in the target single-photon source generating device so that the target single-photon source generating device generates the single-photon source includes:

[0017] After applying a driving signal to the magnetic flux qubit in the target single-photon source generating device, obtaining a driving Hamiltonian of the magnetic flux qubit;

[0018] The driving Hamiltonian of the flux qubit is expressed as follows:

[0019] ;

[0020] Where, is the driving Hamiltonian of the flux qubit, is the left vector of the flux qubit when it is in the first excited state, is the right vector of the flux qubit when it is in the first excited state, is the left vector when the flux qubit is in the ground state, is the right vector when the flux qubit is in the ground state, is the amplitude corresponding to the driving signal applied to the flux bit, is the base, is the imaginary unit, is the frequency corresponding to the driving signal applied to the flux bit, For time;

[0021] adjusting the amplitude and frequency of a driving signal applied to the flux qubit according to the driving Hamiltonian of the flux qubit, and determining a value corresponding to the target second-order correlation function when driving signals of different amplitudes and frequencies are applied to the flux qubit;

[0022] When the value corresponding to the target second-order correlation function is less than 1, determining the amplitude and frequency corresponding to the driving signal applied to the flux qubit to obtain the specified amplitude and the specified frequency;

[0023] When a driving signal of the specified amplitude and the specified frequency is applied to the magnetic flux qubit in the target single-photon source generating device, it is determined that the target single-photon source generating device generates the single-photon source.

[0024] In a specific embodiment of the present application, when the value corresponding to the target second-order correlation function is less than 1, determining the amplitude and frequency corresponding to the driving signal applied to the flux qubit to obtain the specified amplitude and the specified frequency includes:

[0025] When the value corresponding to the target second-order correlation function is less than 1, the amplitude corresponding to applying a driving signal to the flux qubit is determined according to a quantum state leakage model to obtain the specified amplitude; wherein the quantum state leakage model is used to characterize the relationship between the quantum state leakage amount of the flux qubit, the anharmonicity of the flux qubit, and the amplitude corresponding to applying the driving signal to the flux qubit when quantum state leakage occurs in the flux qubit.

[0026] In a specific embodiment of the present application, determining the amplitude corresponding to applying the driving signal to the flux qubit according to the quantum state leakage model to obtain the specified amplitude includes:

[0027] Based on the principle that the quantum state leakage of the flux qubit takes a smaller value, the amplitude corresponding to the driving signal applied to the flux qubit is determined according to the quantum state leakage model to obtain the specified amplitude.

[0028] In order to solve the above technical problems, the present invention further provides a device for generating a single photon source, comprising:

[0029] A light source trigger module is used when a single photon source is to be generated;

[0030] a function acquisition module, configured to acquire a photon second-order correlation function corresponding to a magnetic flux qubit in a target single-photon source generation device, thereby obtaining a target second-order correlation function; wherein the target single-photon source generation device is a single-photon source generation device pre-built using the magnetic flux qubit;

[0031] A signal application module is used to apply a driving signal of a specified amplitude and a specified frequency to the flux quantum bit in the target single-photon source generating device based on the principle that the value corresponding to the target second-order correlation function is less than 1, so that the target single-photon source generating device generates the single-photon source.

[0032] In order to solve the above technical problems, the present invention further provides a device for generating a single photon source, comprising:

[0033] memory for storing computer programs;

[0034] A processor is used to execute the computer program to implement the steps of the method for generating a single photon source as disclosed above.

[0035] In order to solve the above technical problems, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for generating a single photon source as disclosed above are implemented.

[0036] Beneficial effect: In the single-photon source generation method provided by the present invention, when a single-photon source is to be generated, it is necessary to pre-build a single-photon source generation device using magnetic flux quantum bits to obtain a target single-photon source generation device; then, the photon second-order correlation function corresponding to the magnetic flux quantum bit in the target single-photon source generation device is obtained to obtain the target second-order correlation function; finally, based on the principle that the value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and a specified frequency is applied to the magnetic flux quantum bit in the target single-photon source generation device to enable the target single-photon source generation device to generate a single-photon source.

[0037] Compared to related technologies, the anharmonicity of flux qubits is relatively large, typically reaching several GHz. This reduces the probability of a single-photon source quantum state leaking into a highly excited state. Furthermore, when the value corresponding to the target second-order correlation function is less than 1, the light in the target single-photon source generation device will exhibit an anti-bunching effect. Therefore, when flux qubits are used to construct a single-photon source generation device, and based on the principle that the value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and frequency is applied to the flux qubit in the target single-photon source generation device, the state of the flux qubit can be adjusted, relatively reducing the quantum state leakage problem of the flux qubit during the single-photon source emission process and significantly improving the performance of the single-photon source.

[0038] Correspondingly, the single-photon source generation device, equipment, medium and computer program product provided by the present invention also have the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 A flow chart of a method for generating a single photon source provided by an embodiment of the present invention;

[0041] Figure 2 Schematic diagram of generating a single photon source using a Transmon qubit coupled to a superconducting cavity.

[0042] Figure 3 Schematic diagram of the lowest three energy levels of the Transmon qubit;

[0043] Figure 4 Schematic diagram of the lowest three energy levels of the flux qubit;

[0044] Figure 5 A structural diagram of a target single-photon source generating device provided by an embodiment of the present invention;

[0045] Figure 6 A structural diagram of a single-photon source generation device provided by an embodiment of the present invention;

[0046] Figure 7 A structural diagram of a single-photon source generation device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] The terms "including" and "having," as used in the present description and accompanying drawings, and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements and may include steps or elements that are not listed.

[0049] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0050] See Figure 1 , Figure 1 A flow chart of a method for generating a single photon source provided by an embodiment of the present invention, the method comprising:

[0051] Step S11: when a single photon source is to be generated;

[0052] Step S12: obtaining a photon second-order correlation function corresponding to a magnetic flux qubit in a target single-photon source generating device to obtain a target second-order correlation function; wherein the target single-photon source generating device is a single-photon source generating device pre-built using magnetic flux qubits;

[0053] Step S13: Based on the principle that the value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and a specified frequency is applied to the flux quantum bit in the target single-photon source generating device, so that the target single-photon source generating device generates a single-photon source.

[0054] In this embodiment, a method for generating a single-photon source is provided. Using this method to generate a single-photon source can significantly improve the performance of the single-photon source. To enable those skilled in the art to more clearly understand the implementation principles of this application, a method for generating a single-photon source using a Transmon qubit coupled to a superconducting cavity is first described in detail.

[0055] See Figure 2 , Figure 2 This is a schematic diagram of generating a single photon source using a Transmon quantum bit coupled to a superconducting cavity. Figure 2 The system includes a Transmon qubit 01, a control line 02, an emission line 03, and a transmission line 04. The control line 02 is used to control the quantum state of the Transmon qubit 01, the emission line 03 is used to collect and transmit the single photon source emitted by the Transmon qubit 01, and the transmission line 04 is used to read the state of the Transmon qubit 01.

[0056] See Figure 3 , Figure 3 This is a schematic diagram of the lowest three energy levels of the Transmon quantum bit. Figure 3 middle, represents the ground state of the Transmon qubit, represents the first excited state of the Transmon qubit, represents the second excited state of the Transmon qubit. The frequency difference between the first excited state and the ground state of the Transmon qubit is , the frequency difference between the second excited state and the first excited state of the Transmon quantum bit is Among them, the anharmonicity of the Transmon quantum bit The value is usually between -200MHz and -400MHz.

[0057] Corresponding to Figure 3 In the three-level system, when a frequency of And the amplitude is When the driving signal is , the Transmon quantum bit transitions from the ground state to the first excited state due to the anharmonicity of the Transmon quantum bit. The Transmon quantum bit still has a certain probability of transitioning from the first excited state to the second excited state, which will cause quantum state leakage and affect the performance of the single-photon source.

[0058] In this embodiment, to address this issue, a single-photon source generation device is pre-built using flux qubits (fluxonium qubits) to obtain a target single-photon source generation device. When generating a single-photon source, the second-order correlation function of the photons corresponding to the flux qubits in the target single-photon source generation device is obtained to obtain the target second-order correlation function.

[0059] Since the flux qubit itself has a large anharmonicity, which can usually reach several GHz, the probability of the single-photon source quantum state leaking to a highly excited state becomes smaller. Therefore, when the flux qubit is used to build a single-photon source generation device, the leakage problem of the quantum state can be relatively reduced. Figure 4 , Figure 4 Schematic diagram of the lowest three energy levels of the flux qubit. And the amplitude is When the driving signal is , the flux quantum bit transitions from the ground state to the first excited state due to the anharmonicity of the flux quantum bit. The larger the value, the lower the probability that the flux quantum bit will transition from the first excited state to the second excited state, which will relatively reduce the problem of quantum state leakage.

[0060] The photon second-order correlation function of the flux qubit can describe the statistical correlation of photons at different times or spaces. It is a key tool to help us deeply understand and apply quantum optical phenomena. When the target second-order correlation function is less than 1, the light will show an anti-bunching effect, indicating that there is only one photon in the emission line superconducting cavity coupled to the flux qubit. This characteristic can be used for the generation and development of single-photon sources. When the target second-order correlation function is greater than 1, the light will show a bunching effect, indicating that there are multiple photons in the emission line superconducting cavity coupled to the flux qubit. This characteristic cannot be applied to the generation and development of single-photon sources. Therefore, the target second-order correlation function can be used to adjust the state of the flux qubit in the target single-photon source generation device and generate a single-photon source.

[0061] Specifically, based on the principle that the value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and a specified frequency can be applied to the magnetic flux qubit in the target single-photon source generation device. After the driving signal of the specified amplitude and a specified frequency is applied to the magnetic flux qubit in the target single-photon source generation device, if the value corresponding to the target second-order correlation function is less than 1, it indicates that the target single-photon source generation device is capable of generating a single-photon source in this state.

[0062] Compared to related technologies, the anharmonicity of flux qubits is relatively large, typically reaching several GHz. This reduces the probability of a single-photon source quantum state leaking into a highly excited state. Furthermore, when the value corresponding to the target second-order correlation function is less than 1, the light in the target single-photon source generation device will exhibit an anti-bunching effect. Therefore, when flux qubits are used to construct a single-photon source generation device, and based on the principle that the value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and frequency is applied to the flux qubit in the target single-photon source generation device, the state of the flux qubit can be adjusted, relatively reducing the quantum state leakage problem of the flux qubit during the single-photon source emission process and significantly improving the performance of the single-photon source.

[0063] Based on the above embodiment, this embodiment further explains and optimizes the technical solution. Figure 5 , Figure 5 This is a structural diagram of a target single-photon source generating device provided by an embodiment of the present invention. As a preferred embodiment, the target single-photon source generating device includes:

[0064] Flux Qubit 101;

[0065] Control line 102, used to control the quantum state of flux qubit 101;

[0066] The emission line superconducting cavity 103 is used to emit the single photon source generated by the flux quantum bit 101.

[0067] In this embodiment, the structure of the target single-photon source generation device is specifically described. The target single-photon source generation device comprises a flux qubit 101, a control line 102, and an emission line superconducting cavity 103. Specifically, the control line 102 is used to control the quantum state of the flux qubit 101, and the emission line superconducting cavity 103 is used to transmit the single-photon source generated by the flux qubit 101. Due to the relatively large size of the flux qubit 101, it cannot be integrated into the transmission line.

[0068] When the flux qubit 101 and the emission-line superconducting cavity 103 are coupled together, they can exchange photons, allowing the emission-line superconducting cavity 103 to transmit the single photon source emitted by the flux qubit 101. When a driving signal of a certain amplitude and frequency is applied to the control line 102, the quantum state of the flux qubit 101 can be controlled through the control line 102.

[0069] It should be noted that, in order to improve the working performance of the control line 102 when regulating the quantum state of the flux qubit 101 , as a preferred embodiment, the control line 102 can be coupled to the middle position of the flux qubit 101 .

[0070] Obviously, through the technical solution provided in this embodiment, a target single-photon source generation device capable of generating a single-photon source can be constructed using flux quantum bits, control lines and emission line superconducting cavities.

[0071] As a preferred embodiment, the expression of the target second-order correlation function is:

[0072] ;

[0073] Where, is the target second-order correlation function, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the first excited state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 2.

[0074] In this embodiment, the mathematical expression of the target second-order correlation function is specifically described. In practical applications, the photons emitted by the single-photon source should have photon blocking effect and anti-bunching effect. When the target single-photon source generation device emits photons in the superconducting cavity of the emission line, the photons will show a photon blocking effect. At this time, the average number of photons in the superconducting cavity of the emission line does not exceed one. This characteristic can be used in the research and development of single-photon sources. When , it means that there will be multiple photons simultaneously in the emission line superconducting cavity of the target single-photon source generation device. This characteristic cannot be used for the research and development of single-photon sources.

[0075] Obviously, through the technical solution provided in this embodiment, the performance characteristics of photons in the emission line superconducting cavity in the target single-photon source generation device can be more clearly understood.

[0076] As a preferred embodiment, the above step of applying a driving signal of a specified amplitude and a specified frequency to the flux qubit in the target single-photon source generating device based on the principle that the value corresponding to the target second-order correlation function is less than 1, so that the target single-photon source generating device generates a single-photon source, includes:

[0077] After applying a driving signal to the magnetic flux qubit in the target single-photon source generating device, obtaining the driving Hamiltonian of the magnetic flux qubit;

[0078] Among them, the expression of the driving Hamiltonian of the flux quantum bit is:

[0079] ;

[0080] Where, is the driving Hamiltonian of the flux qubit, is the left vector when the flux qubit is in the first excited state, is the right vector when the flux qubit is in the first excited state, is the left vector when the flux qubit is in the ground state, is the right vector when the flux qubit is in the ground state, is the amplitude corresponding to the driving signal applied to the flux bit, is the base, is the imaginary unit, is the frequency corresponding to the driving signal applied to the flux bit, For time;

[0081] adjusting the amplitude and frequency of a driving signal applied to the flux qubit according to the driving Hamiltonian of the flux qubit, and determining the value corresponding to the target second-order correlation function of the flux qubit when driving signals of different amplitudes and frequencies are applied;

[0082] When the value corresponding to the target second-order correlation function is less than 1, the amplitude and frequency corresponding to the driving signal applied to the flux qubit are determined to obtain the specified amplitude and the specified frequency;

[0083] When a driving signal of a specified amplitude and a specified frequency is applied to the flux qubit in the target single-photon source generating device, it is determined that the target single-photon source generating device generates a single-photon source.

[0084] In this embodiment, in the process of allowing the target single-photon source generating device to generate a single-photon source, a driving signal is first applied to the flux qubit in the target single-photon source generating device to change the state of the flux qubit.

[0085] If no driving signal is applied to the flux qubit in the target single-photon source generation device, the expression of the free Hamiltonian of the flux qubit in the target single-photon source generation device is:

[0086] ;

[0087] Where, is the free Hamiltonian of the flux qubit, is the resonant frequency, and are the photon production and annihilation operators of the emission line superconducting cavity, is the first excited state transition frequency of the flux qubit, is the left vector when the flux qubit is in the first excited state, is the right vector when the flux qubit is in the first excited state, is the second excited state transition frequency of the flux qubit, is the left vector when the flux qubit is in the second excited state, is the right vector when the flux qubit is in the second excited state, is the left vector when the flux qubit is in the ground state, is the right vector when the flux qubit is in the ground state, represents the coupling strength between the emission line superconducting cavity and the flux qubit when they are in the first excited state, represents the coupling strength between the emission line superconducting cavity and the flux qubit in the second excited state. In addition, the anharmonicity of the flux qubit is defined. .

[0088] When a driving signal is applied to the flux qubit in the target single-photon source generation device, the driving Hamiltonian of the flux qubit is expressed as: , in this case, the quantum states of the flux qubit and the emission line superconducting cavity will evolve as follows:

[0089] ;

[0090] Where, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 2, is the probability that the flux qubit is in the first excited state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 2, When the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, the flux qubit is in the ground state. When the number of photons in the emission line superconducting cavity coupled with the flux qubit is 2, the flux qubit is in the ground state. It indicates that when the number of photons in the emission line superconducting cavity coupled with the flux qubit is 2, the flux qubit is in the first excited state.

[0091] According to the expression of the target second-order correlation function It can be seen that when or When is easily satisfied, then the target single photon source generating device can generate a single photon source. Close to or greater than ,or, Close to or greater than hour, The value of is close to or even greater than 1, at this time the target single-photon source generating device cannot generate a single-photon source.

[0092] Based on this characteristic of the target second-order correlation function, the amplitude and frequency of the driving signal applied to the flux qubit can be adjusted, thereby achieving the goal of adjusting the state of the flux qubit in the target single-photon source generation device. When the driving signal of different amplitudes and frequencies is applied to the flux qubit, the value corresponding to the target second-order correlation function will change.

[0093] When the value corresponding to the target second-order correlation function is less than 1, it is necessary to determine the amplitude and frequency corresponding to the drive signal applied to the flux qubit to obtain the specified amplitude and frequency. When a drive signal of the specified amplitude and frequency is applied to the flux qubit in the target single-photon source generation device, it indicates that the target single-photon source generation device is capable of generating a single-photon source.

[0094] Obviously, through the technical solution provided by this embodiment, the target single-photon source generating device can generate a single-photon source.

[0095] As a preferred embodiment, the above step: when the value corresponding to the target second-order correlation function is less than 1, determining the amplitude and frequency corresponding to the driving signal applied to the flux qubit to obtain the specified amplitude and specified frequency includes:

[0096] When the value corresponding to the target second-order correlation function is less than 1, the amplitude corresponding to applying a driving signal to the flux qubit is determined according to the quantum state leakage model to obtain a specified amplitude; wherein the quantum state leakage model is used to characterize the relationship between the quantum state leakage amount of the flux qubit, the anharmonicity of the flux qubit, and the amplitude corresponding to applying the driving signal to the flux qubit when the flux qubit undergoes quantum state leakage.

[0097] In this embodiment, since the quantum state leakage model can characterize the relationship between the quantum state leakage amount of the flux qubit, the anharmonicity of the flux qubit, and the amplitude corresponding to the driving signal applied to the flux qubit when the flux qubit undergoes quantum state leakage, in practical applications, in order to better adjust the driving signal applied to the flux qubit, the amplitude corresponding to the driving signal applied to the flux qubit can also be determined according to the quantum state leakage model to obtain a specified amplitude.

[0098] In order to accurately quantify the value of the flux qubit when quantum state leakage occurs, in this embodiment, the mathematical expression of the quantum state leakage model is also specifically described. The expression of the quantum state leakage model is:

[0099] ;

[0100] Where, is the quantum state leakage of the flux qubit, is the amplitude corresponding to the driving signal applied to the flux bit, is the anharmonicity of the flux qubit.

[0101] According to the expression of the quantum state leakage model, if the anharmonicity of the flux quantum bit The larger the value, the more quantum state leakage the flux quantum bit will have. The smaller the size, the better the performance of the single photon source; if the anharmonicity of the flux qubit The smaller it is, the more the quantum state leakage of the flux quantum bit The larger it is, the worse the performance of the single-photon source will be.

[0102] Obviously, through the technical solution provided in this embodiment, the driving signal applied to the flux qubit can be better adjusted.

[0103] As a preferred embodiment, the step of determining the amplitude corresponding to applying the driving signal to the flux qubit according to the quantum state leakage model to obtain the specified amplitude includes:

[0104] Based on the principle that the quantum state leakage of the flux qubit takes a smaller value, the amplitude corresponding to the driving signal applied to the flux qubit is determined according to the quantum state leakage model to obtain the specified amplitude.

[0105] In this embodiment, when determining the amplitude corresponding to the driving signal applied to the flux quantum bit according to the quantum state leakage model, the amplitude corresponding to the driving signal applied to the flux quantum bit can be determined according to the quantum state leakage model based on the principle that the quantum state leakage amount of the flux quantum bit takes a smaller value.

[0106] It can be imagined that when the quantum state leakage of the flux quantum bit is smaller, the performance of the single-photon source generated by the target single-photon source generating device will be better, which will make it easier to process quantum information in subsequent processes, thereby further improving the application value of the technical solution described in this application in practical applications.

[0107] Obviously, through the technical solution provided in this embodiment, the performance of the single photon source generated by the target single photon source generating device can be further improved.

[0108] See Figure 6 , Figure 6 A structural diagram of a single-photon source generation device provided in an embodiment of the present invention, the device comprising:

[0109] A light source triggering module 21 is used when a single photon source is to be generated;

[0110] A function acquisition module 22 is configured to acquire a photon second-order correlation function corresponding to a magnetic flux qubit in a target single-photon source generation device, thereby obtaining a target second-order correlation function; wherein the target single-photon source generation device is a single-photon source generation device pre-built using the magnetic flux qubit;

[0111] The signal application module 23 is used to apply a driving signal of a specified amplitude and a specified frequency to the flux quantum bit in the target single-photon source generating device based on the principle that the value corresponding to the target second-order correlation function is less than 1, so that the target single-photon source generating device generates the single-photon source.

[0112] In a specific embodiment of the present application, the signal applying module 23 includes:

[0113] A Hamiltonian acquisition submodule, configured to acquire a driving Hamiltonian of the magnetic flux qubit after applying a driving signal to the magnetic flux qubit in the target single-photon source generating device;

[0114] The driving Hamiltonian of the flux qubit is expressed as follows:

[0115] ;

[0116] Where, is the driving Hamiltonian of the flux qubit, is the left vector of the flux qubit when it is in the first excited state, is the right vector of the flux qubit when it is in the first excited state, is the left vector when the flux qubit is in the ground state, is the right vector when the flux qubit is in the ground state, is the amplitude corresponding to the driving signal applied to the flux bit, is the base, is the imaginary unit, is the frequency corresponding to the driving signal applied to the flux bit, For time;

[0117] a value determination submodule, configured to adjust the amplitude and frequency of a driving signal applied to the flux qubit according to the driving Hamiltonian of the flux qubit, and determine the value corresponding to the target second-order correlation function when driving signals of different amplitudes and frequencies are applied to the flux qubit;

[0118] a designated signal determination submodule, configured to determine the amplitude and frequency corresponding to the driving signal applied to the flux qubit when the value corresponding to the target second-order correlation function is less than 1, to obtain the designated amplitude and the designated frequency;

[0119] The single-photon source determination submodule is used to determine whether the target single-photon source generating device generates the single-photon source when a driving signal of the specified amplitude and the specified frequency is applied to the magnetic flux quantum bit in the target single-photon source generating device.

[0120] In a specific embodiment of the present application, the designated signal determination submodule includes:

[0121] a designated signal determination unit, configured to determine, when the value corresponding to the target second-order correlation function is less than 1, an amplitude corresponding to applying a driving signal to the flux qubit according to a quantum state leakage model, to obtain the designated amplitude; wherein the quantum state leakage model is configured to characterize, when quantum state leakage occurs in the flux qubit, a relationship between the quantum state leakage amount of the flux qubit, the anharmonicity of the flux qubit, and the amplitude corresponding to applying the driving signal to the flux qubit.

[0122] In a specific embodiment of the present application, the designated signal determination unit includes:

[0123] The designated signal determination subunit is used to determine the amplitude corresponding to the driving signal applied to the flux qubit according to the quantum state leakage model based on the principle that the quantum state leakage amount of the flux qubit takes a smaller value, so as to obtain the designated amplitude.

[0124] An embodiment of the present invention provides a device for generating a single photon source, which has the beneficial effects of the aforementioned method for generating a single photon source.

[0125] See Figure 7 , Figure 7 A structural diagram of a single-photon source generation device provided in an embodiment of the present invention, the device comprising:

[0126] Memory 31, for storing computer programs;

[0127] The processor 32 is configured to execute the computer program to implement the steps of the method for generating a single photon source as disclosed above.

[0128] The single-photon source generation device provided in this embodiment may include but is not limited to a smart phone, a tablet computer, a laptop computer, or a desktop computer.

[0129] The processor 32 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 32 may be implemented using at least one of the following hardware forms: a digital signal processing (DSP), a field-programmable gate array (FPGA), or a programmable logic array (PLA). The processor 32 may also include a main processor and a coprocessor. The main processor is used to process data in the awake state, also known as a central processing unit (CPU); the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 32 may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing content required to be displayed on the display screen. In some embodiments, the processor 32 may also include an artificial intelligence (AI) processor, which is used to handle computational operations related to machine learning.

[0130] The memory 31 may include one or more computer-readable storage media, which may be non-transitory. The memory 31 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In this embodiment, the memory 31 is at least used to store the following computer program 301, wherein, after the computer program is loaded and executed by the processor 32, it can implement the relevant steps of the method for generating a single photon source disclosed in any of the aforementioned embodiments. In addition, the resources stored in the memory 31 may also include an operating system 302 and data 303, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system 302 may include Windows, Unix, Linux, etc. The data 303 may include but is not limited to data involved in the method for generating a single photon source.

[0131] In some embodiments, the single-photon source generating device may further include a display screen 33 , an input / output interface 34 , a communication interface 35 , a power supply 36 , and a communication bus 37 .

[0132] Those skilled in the art will understand that Figure 7 The structure shown in the figure does not constitute a limitation on the device for generating a single photon source, and may include more or fewer components than shown in the figure.

[0133] It is understood that if the methods in the above embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the current technology, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods in each embodiment of the present invention. The aforementioned storage medium includes: a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), an electrically erasable programmable ROM, a register, a hard drive, a removable disk, a CD-ROM, a magnetic disk, or an optical disk, and other media that can store program code.

[0134] An embodiment of the present invention provides a device for generating a single photon source, which has the beneficial effects of the aforementioned method for generating a single photon source.

[0135] Correspondingly, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for generating a single photon source as disclosed above are implemented.

[0136] A computer-readable storage medium provided by an embodiment of the present invention has the beneficial effects of the aforementioned method for generating a single-photon source.

[0137] The present invention also provides a computer program product, which includes a computer program / instruction, and when the computer program / instruction is executed by a processor, implements the steps of the method for generating a single photon source in any of the above embodiments.

[0138] A computer program product provided by an embodiment of the present invention has the beneficial effects of the aforementioned method for generating a single photon source.

[0139] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0140] The above is a detailed introduction to the method for generating a single photon source and related equipment provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for generating a single photon source, characterized in that: include: When a single photon source is to be generated; Obtaining a photon second-order correlation function corresponding to a magnetic flux qubit in a target single-photon source generating device to obtain a target second-order correlation function; wherein the target single-photon source generating device is a single-photon source generating device pre-built using the magnetic flux qubit; Based on the principle that the numerical value corresponding to the target second-order correlation function is less than 1, a driving signal of a specified amplitude and a specified frequency is applied to the flux quantum bit in the target single-photon source generating device, so that the target single-photon source generating device generates the single-photon source.

2. The method for generating a single photon source according to claim 1, wherein: The target single-photon source generating device comprises: the flux qubit; A control line for regulating the quantum state of the flux qubit; An emission line superconducting cavity is used to emit the single photon source generated by the flux quantum bit.

3. The method for generating a single photon source according to claim 2, wherein: The control line is coupled to a middle position of the flux qubit.

4. A method for generating a single photon source according to claim 3, characterized in that: The expression of the target second-order correlation function is: ； Where, is the target second-order correlation function, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the first excited state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 1, is the probability that the flux qubit is in the ground state when the number of photons in the emission line superconducting cavity coupled to the flux qubit is 2.

5. The method for generating a single photon source according to claim 4, wherein: The step of applying a driving signal of a specified amplitude and a specified frequency to the magnetic flux qubit in the target single-photon source generating device based on the principle that the value corresponding to the target second-order correlation function is less than 1, so that the target single-photon source generating device generates the single-photon source, includes: After applying a driving signal to the magnetic flux qubit in the target single-photon source generating device, obtaining a driving Hamiltonian of the magnetic flux qubit; The driving Hamiltonian of the flux qubit is expressed as follows: ； Where, is the driving Hamiltonian of the flux qubit, is the left vector of the flux qubit when it is in the first excited state, is the right vector of the flux qubit when it is in the first excited state, is the left vector when the flux qubit is in the ground state, is the right vector when the flux qubit is in the ground state, is the amplitude corresponding to the driving signal applied to the flux bit, is the base, is the imaginary unit, is the frequency corresponding to the driving signal applied to the flux bit, For time; adjusting the amplitude and frequency of a driving signal applied to the flux qubit according to the driving Hamiltonian of the flux qubit, and determining a value corresponding to the target second-order correlation function when driving signals of different amplitudes and frequencies are applied to the flux qubit; When the value corresponding to the target second-order correlation function is less than 1, determining the amplitude and frequency corresponding to the driving signal applied to the flux qubit to obtain the specified amplitude and the specified frequency; When a driving signal of the specified amplitude and the specified frequency is applied to the magnetic flux qubit in the target single-photon source generating device, it is determined that the target single-photon source generating device generates the single-photon source.

6. The method for generating a single photon source according to claim 5, characterized in that: When the value corresponding to the target second-order correlation function is less than 1, determining the amplitude and frequency corresponding to the driving signal applied to the flux qubit to obtain the specified amplitude and the specified frequency, including: When the value corresponding to the target second-order correlation function is less than 1, the amplitude corresponding to applying a driving signal to the flux qubit is determined according to a quantum state leakage model to obtain the specified amplitude; wherein the quantum state leakage model is used to characterize the relationship between the quantum state leakage amount of the flux qubit, the anharmonicity of the flux qubit, and the amplitude corresponding to applying the driving signal to the flux qubit when quantum state leakage occurs in the flux qubit.

7. A method for generating a single photon source according to claim 6, characterized in that: Determining the amplitude corresponding to applying a driving signal to the flux qubit according to the quantum state leakage model to obtain the specified amplitude includes: Based on the principle that the quantum state leakage of the flux qubit takes a smaller value, the amplitude corresponding to the driving signal applied to the flux qubit is determined according to the quantum state leakage model to obtain the specified amplitude.

8. A device for generating a single photon source, characterized in that: include: A light source trigger module is used when a single photon source is to be generated; a function acquisition module, configured to acquire a photon second-order correlation function corresponding to a magnetic flux qubit in a target single-photon source generation device, thereby obtaining a target second-order correlation function; wherein the target single-photon source generation device is a single-photon source generation device pre-built using the magnetic flux qubit; A signal application module is used to apply a driving signal of a specified amplitude and a specified frequency to the flux quantum bit in the target single-photon source generating device based on the principle that the value corresponding to the target second-order correlation function is less than 1, so that the target single-photon source generating device generates the single-photon source.

9. A device for generating a single photon source, characterized in that: include: memory for storing computer programs; A processor, configured to execute the computer program to implement the steps of the method for generating a single photon source as claimed in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for generating a single photon source according to any one of claims 1 to 7 are implemented.

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