Methods, apparatus, media, and devices for determining photon emission parameters

Abstract

The present application relates to a method, device, medium and equipment for determining photon emission parameters, the method comprising: obtaining power of photons when the photons arrive at a receiving end from a transmitting end via free space; determining power loss of the photons occurring in a transmission process of the photons from the transmitting end to the receiving end via the free space, the power loss comprising power loss of the photons occurring on an optical device in the transmitting end, power loss of the photons occurring in the free space and power loss of the photons occurring on an optical device in the receiving end; and determining emission power of the photons at the transmitting end based on the power of the photons when the photons arrive at the receiving end from the transmitting end via the free space and the power loss occurring in the transmission process. The present application can determine photon emission parameters matched with different receiving ends of a distributed quantum computer based on the different receiving ends, so as to ensure that the receiving ends can receive sufficient photons to meet the requirements of the receiving ends on the number or power of the photons.

Description

Technical Field

[0001] This invention relates to the fields of quantum computing and quantum communication technologies, and particularly to methods, apparatus, media, and devices for determining photon emission parameters. Background Technology

[0002] In quantum mechanics-related applications such as quantum repeaters, quantum computing, quantum communication, and quantum sensing, quantum networks composed of distributed quantum computers can effectively improve the processing capacity and efficiency of qubits, thus playing a role in replacing supercomputing centers. Existing quantum computers, such as ion trap quantum computers, all use photons (or single photons) as the medium, forming quantum networks through the interaction of photons to achieve geographically interconnected connections. However, a practical challenge lies in the fact that photons suffer varying degrees of loss during transmission due to the devices used and the transmission distance. This photon loss makes it difficult for the receiver in the quantum network to receive an appropriate number or power of photons, thus affecting transmission capability and efficiency. Summary of the Invention

[0003] To address the technical problems existing in the prior art, this invention proposes a method, apparatus, medium, and device for determining photon emission parameters. These methods and devices can determine the photon emission parameters of the transmitting end, enabling the transmitting end to meet the receiving end's requirements for the number or power of photons when emitting photons based on the photon emission parameters.

[0004] To address the aforementioned technical problems, according to one aspect of the present invention, a method for determining photon emission parameters is provided, comprising: acquiring the power of a photon as it travels from an emitter to a receiver via free space; determining the power loss incurred by the photon during its transmission from the emitter to the receiver via free space, the power loss including power loss incurred by the photon in an optical device at the emitter, power loss in free space, and power loss in an optical device at the receiver; and determining the emission power of the photon at the emitter based on the power of the photon as it travels from the emitter to the receiver via free space and the power loss incurred during the transmission.

[0005] Optionally, the power loss of the photon in free space is determined based on the distance between the transmitter and receiver and the attenuation effect of the atmosphere in free space on the photon.

[0006] Optionally, the attenuation effect includes at least one of the attenuation effect of atmospheric turbulence on photon generation, the attenuation effect of atmospheric scattering on photon generation, and the attenuation effect of atmospheric visibility on photon generation.

[0007] Optionally, the method further includes: determining the emission frequency of the photon at the transmitting end based on the emission power of the photon at the transmitting end and the energy of each photon.

[0008] Optionally, the transmitter is a quantum computer, and the photons originate from an ion trap device within the quantum computer.

[0009] Optionally, the photon is ultraviolet light with a wavelength of 369 nm.

[0010] According to another aspect of the present invention, an apparatus for determining photon emission parameters is provided, comprising a receive power acquisition unit, a power loss determination unit, and a transmit power determination unit, wherein the receive power acquisition unit is configured to acquire the power of a photon as it travels from an emitter to a receiver via free space; the power loss determination unit is configured to determine the power loss of the photon during its transmission from the emitter to the receiver via free space, the power loss including power loss occurring on optics at the emitter, power loss occurring in free space, and power loss occurring on optics at the receiver; and the transmit power determination unit is configured to determine the transmit power of the photon at the emitter based on the power of the photon as it travels from the emitter to the receiver via free space and the power loss occurring during the transmission.

[0011] Optionally, the power loss determination unit determines the power loss of the photon in free space based on the distance between the transmitter and receiver and the attenuation effect of the atmosphere in free space on the photon.

[0012] According to another aspect of the invention, the invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned method for determining photon emission parameters.

[0013] According to another aspect of the present invention, a computing device is provided, comprising: a processor and a memory, the memory storing a computer program that, when executed by the processor, implements the aforementioned method for determining photon emission parameters.

[0014] This invention can determine the photon emission parameters that match the different receivers of a distributed quantum computer, so as to ensure that the receiver can receive enough photons to meet the receiver's requirements for the number or power of photons, thereby ensuring the processing efficiency of distributed quantum data. Attached Figure Description

[0015] The preferred embodiments of the present invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0016] Figure 1 This is a schematic diagram of a distributed quantum computer network model structure according to an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the structural principle of a photon transmission path device according to an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of a photon transmission path according to an embodiment of the present invention;

[0019] Figure 4 This is a flowchart illustrating a method for determining transmission parameters according to an embodiment of the present invention;

[0020] Figure 5 This is a schematic flowchart of a method for determining power loss during photon transmission according to an embodiment of the present invention;

[0021] Figure 6 This is a flowchart illustrating a method for obtaining a transmission frequency according to an embodiment of the present invention;

[0022] Figure 7 This is a schematic block diagram of a transmission parameter determination device according to an embodiment of the present invention;

[0023] Figure 8A This is a schematic diagram of the control principle structure of an ion trap device serving as the emitter according to an embodiment of the present invention; and

[0024] Figure 8B This is a schematic diagram of the control principle structure of a distributed quantum computer system according to an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the following detailed description, reference can be made to the accompanying drawings, which form part of this application and illustrate specific embodiments of the present application. In the drawings, similar reference numerals describe substantially similar components in different figures. Specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to implement the technical solutions of the present application. It should be understood that other embodiments may also be utilized, or structural, logical, or electrical changes may be made to the embodiments of the present application.

[0027] In distributed quantum computer networks, such as Figure 1In the network model shown, single photons generated by quantum computers 10a and 11a interact within beamsplitter 21a after propagation. The single photons detected by detectors 22a and 23a, connected to beamsplitter 21a, must meet certain counting requirements to determine the interconnectivity of the computers. To increase the probability of the detectors detecting photons in the beamsplitter, the number or power of photons emitted by the quantum computers must not be less than a certain value. To meet this requirement, this invention provides a method and apparatus for determining photon emission parameters.

[0028] Figure 2 This is a schematic diagram illustrating the structural principle of a photon transmission path device according to an embodiment of the present invention. In this embodiment, the photon transmission path device includes multiple ion trap devices 10, 11, 12, etc., and multiple photon correlation devices 20, 21, etc., wherein the multiple ion trap devices 10, 11, 12, etc., and the photon correlation devices 20, 21, etc., can be distributed in different locations. In this embodiment, photons emitted by any two ion trap devices are detected in a photon correlation device. Whether the detected photons interact, such as whether they are in an entangled state, is used to determine whether the two ion trap devices are interconnected. This embodiment uses an ion trap device as a quantum computer; of course, other types of quantum computers can also be used, with the same principle, and therefore will not be described in detail here.

[0029] Figure 3This is a schematic diagram of a photon transmission path, including an ion trap device 10 as the transmitter, free space in the atmosphere, and a photon correlation device 20 as the receiver. Taking the ion trap device 10 as an example, the transmission link provided by the ion trap device 10 includes at least an ion trap 101, a mirror assembly 102, an optical fiber coupler 103, a starting optical fiber 104, and a transmitter 105. In one embodiment, the ion trap 101, the mirror assembly 102, and the optical fiber coupler 103 are located in one device. The photon output end of the ion trap 101 is opposite to the incident reflection surface in the mirror assembly 102, and the output reflection surface in the mirror assembly 102 is opposite to the optical fiber coupler 103. The optical fiber coupler 103 is coupled to one end of the starting optical fiber 104, and the other end of the starting optical fiber 104 is connected to the transmitter 105. The control device in ion trap 101 operates the ions within the ion trap, causing energy level transitions and emitting photons. These photons are emitted through the confinement channel in ion trap 101, pass through mirror assembly 102 and fiber optic coupling frame 103, enter the starting fiber 104, and then enter the transmitting device 105. From the transmitting device 105, the photons enter free space, which may be a set of lenses or a single lens. In this embodiment, the distance between the transmitter and receiver in the distributed quantum computer network is 2km-10km. To reduce environmental interference, the transmitting device 105 is typically located at a high, unobstructed position. The photons are emitted into free space via the transmitting device 105, and through a free space link, are received and detected by a photon correlation device at the receiving end. In this embodiment, taking photon correlation device 20 as an example, photon correlation device 20 includes a photon receiver 201 and photon detectors 202 and 203 connected to it. In this embodiment, the photon receiver 201 includes a set of lenses 2011 and a beam splitter 2012. Photons transmitted from free space are incident on the incident surface of beam splitter 2012 through lens 2011 in photon receiver 201, and exit after a predetermined separation angle. Photon detectors 202 and 203 are, for example, detectors based on silicon avalanche photodiodes, whose photosensitive areas are opposite to the exit optical path of the beam splitter, so as to receive photons passing through beam splitter 2012 and generate induced electrical signals.

[0030] Due to transmission losses, in order to ensure that the receiver receives a sufficient number or power of photons, the transmitter needs to emit photons according to certain transmission parameters. The process for determining these transmission parameters is as follows: Figure 4 As shown, it includes the following steps:

[0031] Step S1: Obtain the power of the photon as it travels from the transmitter to the receiver via free space.

[0032] Step S2: Determine the power loss that occurs during the transmission of photons from the transmitter to the receiver via free space. The power loss includes the power loss of photons in the optical devices at the transmitter, the power loss of photons in free space, and the power loss of photons in the optical devices at the receiver.

[0033] Step S3: Determine the transmission power of the photon at the transmitter based on the power of the photon as it travels from the transmitter to the receiver via free space and the power loss that occurs during the transmission process.

[0034] In step S1, the power of a photon as it travels from the transmitter to the receiver via free space is, for example, a power threshold P0 determined to meet the requirements for photon detection at the receiver. If the requirement for photon detection at the receiver is a quantity threshold, the quantity threshold is converted into a power threshold. Different applications of photons at the receiver result in different requirements for photon detection, and therefore different corresponding power thresholds P0.

[0035] In step S2, when determining the power loss that occurs during the transmission of photons from the transmitter to the receiver via free space, in one embodiment, as follows: Figure 5 As shown, the process of determining the power loss of photons during their transmission from the transmitter to the receiver via free space includes the following steps:

[0036] Step S21: Calculate the power loss δ1 of photons occurring on the optical devices in the receiver. Further, obtain the optical devices in the receiver and their corresponding optical parameters, and calculate the power loss of photons occurring on the optical devices based on the optical parameters.

[0037] Step S22: Calculate the power loss δ2 of photons in free space based on the distance between the transmitter and receiver and the attenuation effect of the atmosphere in free space on photons. The attenuation effect includes at least one of the attenuation effects of atmospheric turbulence, atmospheric scattering, and atmospheric visibility.

[0038] Step S23: Calculate the power loss δ3 that occurs when photons pass through the optical devices at the transmitter.

[0039] In one embodiment, in step S22, the attenuation effect of the atmosphere on photons is determined based on the photon attenuation rate formula 1-1 in the free space of the atmosphere.

[0040]

[0041] Where D is the photon attenuation rate in free space; β is the atmospheric turbulence influence factor, β=μη, μ is the optical coupling efficiency, and η is the turbulent transmission efficiency. For horizontal transmission distances of 2km-10km, μ is taken as… λ0 is 550nm, λ is the wavelength of the photon emitted by the transmitter, in nm; V is the atmospheric visibility, in km; q is a constant corresponding to different atmospheric visibility; L is the horizontal transmission distance of the photon in free space, in km.

[0042] In step S3, the transmission power of the photon at the transmitting end is determined by calculating from the power threshold P0 at the receiving end, starting from the power threshold P0 at the receiving end, based on the obtained power threshold P0 when the photon arrives at the receiving end via free space and the power losses δ1, δ2, and δ3 that occur during the transmission process.

[0043] Among them, with Figure 3 Taking the photon transmission path shown as an example, the photons transmitted in this device are ultraviolet photons with a wavelength of 369nm. When ultraviolet photons with a wavelength of 369nm are transmitted through the photon transmission path of this embodiment, according to specific requirements, assuming that the minimum photon power detected by the receiving end, i.e., the power threshold, is -135dBm, the collection efficiency of the receiving device 201 is about 10%, and the efficiency of the detector 202 is about 30%, then the loss δ of the receiving device 201 is... 201 The loss δ is calculated according to formula 2-1. 201 It is 10dB.

[0044]

[0045]

[0046] Similarly, when the detector efficiency is approximately 30%, the detector loss δ 202 Approximately 5.2 dB. Therefore, the total loss at the receiver is δ1 = δ 201 +δ 202 =10 + 5.2 = 15.2 dB.

[0047] Let the receiving power of the receiving device at the receiving end be P1, and the power threshold of the receiving end be P0. The minimum photon power should be -135dBm, so the receiving power P1 of the receiving device 201 at the receiving end can be calculated.

[0048] P1=P0+δ1=-135+15.2=-119.8dBm

[0049] The received power P1 obtained at this time is also the power after transmission through free space.

[0050] The attenuation rate D of a photon in free space is calculated based on the photon attenuation rate formula 1-1.

[0051] D=βe -αL 1-1

[0052] β is the atmospheric turbulence influence factor, β = μη, μ is the optical coupling efficiency, and η is the turbulent transmission efficiency. For horizontal transmission distances of 2km-10km, the values ​​of μ range from [0.95-1], and the values ​​of η range from [0.9-1]; α is the atmospheric scattering influence factor. λ0 is 550nm, λ is the wavelength of the photon emitted by the transmitter, in nm; V is the atmospheric visibility, in km; q is a constant corresponding to different atmospheric visibility; L is the horizontal transmission distance of the photon in free space, in km.

[0053] In this embodiment, the horizontal transmission distance between the transmitter and receiver is 10 km, i.e., L = 10 km, λ0 is 550 nm, λ is 369 nm, V is 10 km, and the corresponding q is 1.3. When β is 1, i.e., turbulence is not considered, the calculated attenuation rate D = 0.0014. According to Formula 2-1, the loss δ2 through free space is 28.5 dB.

[0054] Therefore, the power P2 of the photon when it enters free space can be obtained.

[0055] P2=P1+δ2=-119.8+28.5=-91.3dBm

[0056] The power P2 when entering free space is also the power emitted through the ion trap device 10.

[0057] In one embodiment, the loss of the mirror assembly in the ion trap device 10 is negligible, the coupling efficiency of the fiber optic coupler 103 is 50%, and the loss parameters of the starting fiber 104 are a length of 100m and a loss efficiency of 50dB / km. Therefore, the loss of the fiber optic coupler 103 is 3dB, the loss of the starting fiber 104 is 5dB, and the total loss δ3 of the ion trap device 10, which serves as the transmitting end, is 8dB.

[0058] The minimum emission power P3 emitted by the ion trap 101 as a single-photon source is:

[0059] P3=P2+δ3=-91.3+8=-83.3dBm

[0060] When the power threshold for photons reaching the receiver to meet the detection requirements is -135dBm, after the aforementioned... Figure 3The transmission link determines that the minimum power emitted by ion trap 101 should be -83.3 dBm, meaning the emission parameters of ion trap 101 are that the emission power is not less than -83.3 dBm. When a distributed ion trap quantum computer interconnects with other distributed ion trap quantum computers, in order to meet processing efficiency, its minimum emission power can be determined based on the minimum power requirement of the receiving end, thus satisfying both processing efficiency and improving the photon reception and detection rate.

[0061] Furthermore, the emission frequency of photons at the transmitting end can be determined based on the emission power and energy of each photon. The process for determining the emission frequency is as follows: Figure 6 As shown, it includes the following steps:

[0062] Step S41: Determine the photon emission energy E1 per second based on the minimum emission power P3.

[0063] E1 = E 1 *1s=4.67E-12J

[0064] Where mW is the unit of power and J is the unit of energy.

[0065] Step S42: Calculate the energy E of each photon based on Planck's formula. p For ultraviolet photons with a wavelength of 369 nm, according to Planck's formula E p =hv can be used to calculate the energy of an ultraviolet photon: where h = 6.626E-34J·s, which is Planck's constant.

[0066] c is the speed of light, c = 3E + 8m / s

[0067] Step S43, based on the emission energy E1 and a photon energy E per second. p The calculated emission frequency f of the photon.

[0068]

[0069] After rounding to the nearest integer, f = 1.0E + 7, meaning it emits 10 per second. 7 One photon is emitted every 100 ns.

[0070] This invention also provides an apparatus for determining photon emission parameters, hereinafter referred to as the emission parameter determining apparatus. For example... Figure 7The diagram shown is a schematic block diagram of a transmission parameter determination device 400 according to an embodiment of the present invention. The transmission parameter determination device 400 includes a received power acquisition unit 401, a power loss determination unit 402, and a transmission power determination unit 403. The received power acquisition unit 401 is configured to acquire the power of a photon as it travels from the transmitter to the receiver via free space. The power loss determination unit 402 is configured to determine the power loss incurred by the photon during its transmission from the transmitter to the receiver via free space. This power loss includes power loss occurring on optical devices at the transmitter, power loss occurring in free space, and power loss occurring on optical devices at the receiver. The transmission power determination unit 403 is configured to determine the transmission power of the photon at the transmitter based on the power of the photon as it travels from the transmitter to the receiver via free space and the power loss occurring during the transmission process.

[0071] The receiving power acquisition unit 401 can acquire the power of photons as they travel from the transmitter to the receiver via free space, for example, the power threshold P0 described in the aforementioned method. The power loss determination unit 402 can acquire photon transmission path parameters, including at least the parameters of the optical devices used at the transmitter and receiver, and parameters in free space, thereby calculating the power loss δ1 occurring on the optical devices at the receiver, the power loss δ2 occurring in free space, and the power loss δ3 occurring on the optical devices at the transmitter. The transmitting power determination unit 403 calculates the transmitting power of the photons at the transmitter starting from the power threshold P0 at the receiver.

[0072] Furthermore, the emission parameter determination device 400 also includes an emission frequency determination unit 404. The emission frequency determination unit 404 is connected to the emission power determination unit 403, and determines the photon emission energy E1 per second based on the minimum emission power P3; calculates the energy Ep of each photon based on Planck's formula; and calculates the energy based on the emission energy E1 per second and a photon energy E... p The calculated emission frequency f of the photon.

[0073] When performing power calculations, the power loss determination unit 402, when requiring real-time atmospheric parameters such as atmospheric visibility and the corresponding constant q value, queries a meteorological website to obtain the visibility; it then looks up the corresponding q value using a table corresponding to visibility and the constant q value. When calculating the photon attenuation rate D in the current atmospheric free space, considering the turbulence influence factor, the power loss determination unit 402 can query current weather data to determine the values ​​of the optical coupling efficiency μ and the turbulent transmission efficiency η within the turbulence influence factor.

[0074] In one embodiment, the emission parameter determination device 400 of the present invention is applied to the control device of any quantum computer serving as the transmitter, such as... Figure 8A As shown, in the distributed ion trap quantum computer system, the ion trap device serves as the quantum computer. Each ion trap device 10 includes an ion trap control device 1011 and an ion trap 101. The emission parameter determination device 400 is located in the ion trap control device 1011. When the ion trap 101 needs to emit a single photon, the ion trap control device 1011 controls the ion trap 101 to emit a single photon according to the emission parameters determined by the emission parameter determination device 400.

[0075] In another embodiment, such as Figure 8B As shown, the emission parameter determination device 400 of the present invention is applied in the overall system control device 30 of a distributed quantum computer system, and the system control device 30 is connected to each quantum computer in the system. In this embodiment, an ion trap device is still used as an example of a quantum computer. The system control device 30 is connected to each ion trap device in the system, and the ion trap device includes... Figure 8A The ion trap control device is shown. The system control device 30 sends the emission parameters determined by the emission parameter determination device 400 to the corresponding ion trap device. Alternatively, when an ion trap device, such as ion trap device 10, needs to emit a single photon, its ion trap control device 1011 sends a parameter request to the system control device 30. The system control device 30 calculates the required emission parameters based on the parameter request and sends the calculated emission parameters to the ion trap control device 1011. The ion trap control device 1011 then controls the ion trap 101 to emit photons according to the emission parameters.

[0076] In a specific implementation, the ion trap control device 1011 includes a processor and a memory storing computer program instructions. When the processor executes the computer program instructions, the emission parameter determination device 400 obtains the emission parameters. When the ion trap control device acts as a photon emitter, it operates the ion trap according to the photon emission parameters so that the ion trap emits photons that meet the power requirements of the receiver.

[0077] In one embodiment, each distributed quantum computer stores the optical device parameters in its photon transmission path (which it acts as a transmitter), the optical device parameters for each receiver it can interconnect with, and the corresponding transmission distance in free space. When the emission parameter determination device 400 is located within the distributed quantum computer, it calculates the emission parameters for sending photons to each receiver based on these parameters. When needed, the quantum computer controls single-photon sources such as ion traps to emit photons based on the emission parameters. When the emission parameter determination device 400 is located in the overall system control device 30 of the distributed quantum computer system, each distributed quantum computer sends a parameter request to the system control device 30, including the optical device parameters used in the photon transmission path and the free space parameters, so that the emission parameter determination device 400 in the system control device 30 can calculate the emission parameters for sending photons to the corresponding receiver based on these parameters and return them to the distributed quantum computer.

[0078] In another embodiment, the overall system control device 30 of the distributed quantum computer system stores optical device parameters for all photon transmission paths acting as transmitters, optical device parameters for all photon transmission paths acting as receivers, and atmospheric free-space parameters such as the transmission distance in atmospheric free space from each transmitter to the receiver. In one embodiment, a transmission parameter determination device 400 calculates the transmission parameters for each transmitter when sending photons to different receivers based on these parameters, and sends multiple transmission parameters to the quantum computers acting as transmitters. When a quantum computer needs to transmit photons, it determines the corresponding transmission parameters based on the receiver. In another embodiment, when a distributed quantum computer in the system needs to send photons to a receiver, it sends a request to the system control device 30, including a transmitter identifier and a receiver identifier in the request. The system control device 30 retrieves the corresponding optical device parameters and atmospheric free-space parameters from its internal memory based on the transmitter identifier and receiver identifier, calculates the transmission parameters, and returns them to the distributed quantum computer that sent the request. When the transmission parameter determination device 400 is located in a single distributed quantum computer, the distributed quantum computer requests parameter data used in the calculation process from the system control device 30 when calculating the transmission parameters, such as providing the transmitter identifier and receiver identifier. The system control device 30 retrieves the corresponding parameters from its internal memory based on the transmitter identifier and receiver identifier and returns them to the distributed quantum computer that sent the request. The transmission parameter determination device 400 calculates the transmission parameters based on the received parameter data.

[0079] In this invention, the effects of atmospheric scattering and atmospheric turbulence are considered when calculating the attenuation rate D of photons passing through free space. Since the photon transmission path in this invention is applied to short-range line-of-sight communication, the impact of atmospheric scattering on photon transmission is far greater than that of atmospheric turbulence. Therefore, the calculation of the photon transmission attenuation rate D is primarily based on scattering effects, and a turbulence influence factor is determined according to different weather conditions.

[0080] The principle for determining the turbulence influence factor is as follows:

[0081] During optical signal transmission, atmospheric turbulence affects the jitter of the optical signal and the strength of the optical coupling signal. Since this invention focuses on temporal information rather than spatial imaging, atmospheric turbulence ultimately affects the optical path loss and optical coupling efficiency. The relationship between atmospheric turbulence and the optical path loss is shown in Equation 3-1:

[0082]

[0083] Wherein, parameter η is the turbulent transmission efficiency.<I(r,L)> I(r,L) represents the intensity of a Gaussian beam with turbulence, while I(r,L) represents the intensity of a Gaussian beam without turbulence.

[0084] in<I(r,L)> The expression is shown in Formula 3-2 below, where A0 is the amplitude of the beam at the transmitting end, W0 is the beam radius at the transmitting end, and W... LT The actual laser beam radius is defined as the extended laser spot radius. r is the distance from the center of the actual laser spot to the center of the laser spot in the absence of turbulence.

[0085]

[0086] Among them, W LT The expression is shown in Formula 3-3:

[0087]

[0088] The Rytov exponential function With atmospheric refractive index structural parameters The relationship between wavenumber k and distance L is shown in Formula 3-4:

[0089]

[0090] Where Λ is a user-defined function.

[0091] The expression for I(r,L) is shown in Formula 3-5:

[0092]

[0093] Where W is the radius of the light spot at the receiving end.

[0094] Since the present invention transmits indivisible photons, the parameters W0 and W in the above formula are therefore... LT Since W and η are the same value, the parameter η depends on the atmospheric refractive index structure parameter. Atmospheric refractive index structure parameters It is related to weather conditions. Experiments show that under normal weather conditions, at a horizontal transmission distance of 2km-10km, the turbulent transmission efficiency can reach 0.999772 under good weather conditions, which can be ignored. However, under poor weather conditions, when atmospheric turbulence is strong, the turbulent transmission efficiency in the 2km-10km range is above 0.89901, which is rounded to 0.9. The turbulent transmission efficiency η calculated by the above formula has a range of [0.9-1].

[0095] In addition, since different cloud densities in space lead to different optical coupling efficiencies, in order to ensure the receiving power or the number of photons received at the receiver, this embodiment adds optical coupling efficiency μ as a turbulence influence factor β on the basis of turbulence transmission efficiency η, that is, β=μη, where μ ranges from [0.95-1] and η ranges from [0.9-1].

[0096] This invention prioritizes the scattering effect, which has the greatest impact, and secondarily considers turbulence effects when calculating photon losses in free-space transmission links, thus increasing the accuracy of the calculations. Based on the characteristics of short-range photon communication, this invention calculates the losses in the transmission path using the aforementioned method, and then determines the photon emission parameters at the transmitting end according to different requirements of the receiving end, thereby meeting the processing requirements of distributed quantum computer systems.

[0097] In another aspect, the present invention also provides a computer-readable storage medium storing computer program instructions, which, when executed by a processor, obtain emission parameters according to the aforementioned photon emission parameter determination method. The storage medium may be, for example, various types of memory, such as internal storage units like hard disks or RAM of a control device, or it may be a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., provided with the control device.

[0098] The present invention also provides a computer program product, which includes computer program instructions. The computer program product may be an application package, an application installation package, or a program written in a programming language. This program can be executed by the processor in the aforementioned ion trap control device or system control device to obtain the computer program instructions therein, thereby obtaining the emission parameters.

[0099] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of the invention.

Claims

1. A method for determining photon emission parameters, characterized in that, include: To obtain the power of a photon as it travels from the transmitter through free space to the receiver; Determine the power loss that occurs during the transmission of photons from the transmitter to the receiver via free space, including the power loss of photons in the optical devices at the transmitter, the power loss of photons in free space, and the power loss of photons in the optical devices at the receiver. as well as The emission power of the photon at the transmitter is determined based on the power of the photon as it travels from the transmitter to the receiver via free space and the power loss that occurs during the transmission process.

2. The method according to claim 1, characterized in that, The power loss of photons in free space is determined based on the distance between the transmitter and receiver and the attenuation effect of the atmosphere in free space on the photons.

3. The method according to claim 2, characterized in that, The attenuation effect includes at least one of the following: the attenuation effect of atmospheric turbulence on photon generation, the attenuation effect of atmospheric scattering on photon generation, and the attenuation effect of atmospheric visibility on photon generation.

4. The method according to claim 1, characterized in that, Also includes: The emission frequency of photons at the transmitter is determined based on the emission power of photons at the transmitter and the energy of each photon.

5. The method according to claim 1, characterized in that, The transmitter is a quantum computer, and the photons originate from an ion trap device within the quantum computer.

6. The method according to claim 1, characterized in that, The photons are ultraviolet light with a wavelength of 369 nm.

7. An apparatus for determining photon emission parameters, characterized in that, include: The receiving power acquisition unit is configured to acquire the power of photons when they arrive at the receiving end from the transmitter via free space. The power loss determination unit is configured to determine the power loss of photons during their transmission from the transmitter to the receiver via free space, the power loss including the power loss of photons in the optical devices at the transmitter, the power loss of photons in free space, and the power loss of photons in the optical devices at the receiver. as well as The transmission power determination unit is configured to determine the transmission power of the photon at the transmitter based on the power of the photon as it travels from the transmitter to the receiver via free space and the power loss that occurs during the transmission process.

8. The apparatus according to claim 7, characterized in that, The power loss determination unit determines the power loss of photons in free space based on the distance between the transmitter and receiver and the attenuation effect of the atmosphere in free space on photons.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method for determining photon emission parameters as described in any one of claims 1 to 6.

10. A computing device, characterized in that, include: processor; as well as A memory storing a computer program that, when executed by a processor, implements the method for determining photon emission parameters as described in any one of claims 1 to 6.

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