Microwave single-photon detector detection efficiency test method, device and program product

Abstract

The invention relates to a microwave single-photon detector detection efficiency testing method and device and a program product. The method comprises the following steps: according to a first microwave coherent signal, a second microwave coherent signal and a third microwave coherent signal, determining a corresponding relation between the response rate of a microwave single-photon detector and the average photon number entering the microwave single-photon detector; the average photon number entering the microwave single-photon detector is the average photon number of the third microwave coherent signal; converting the quantum state of the third microwave coherent signal into a target superposition state of a plurality of photon number states according to the average photon number; and according to the target superposition state of the multiple photon number states and a preset response rate calculation relation of the microwave single-photon detector, fitting a corresponding relation between the response rate of the microwave single-photon detector and the average photon number entering the microwave single-photon detector to obtain the detection efficiency of the microwave single-photon detector. By adopting the method, the measurement accuracy of the detection efficiency of the microwave single-photon detector can be improved.

Description

Technical Field

[0001] The present application relates to the field of single-photon detection technology, and in particular to a method, device and program product for testing the detection efficiency of a microwave single-photon detector. Background Art

[0002] Single-photon detectors are the most sensitive detectors that can detect the energy of a single photon. They are of great value in many scientific research and practical applications. Microwave single-photon detection has broad application prospects in fields such as quantum information processing and dark matter detection. However, due to the extremely low energy of single photons in the microwave band, single-photon detection is very difficult, and single-photon detection methods in traditional optical bands are difficult to apply. With the development of circuit quantum electrodynamics systems based on superconducting quantum bits, microwave single-photon detection has gradually become possible, and some microwave single-photon detection schemes based on superconducting quantum bits have emerged. Among them, the scheme based on controlling the phase gate between microwave photons and superconducting quantum bits, with its characteristics of quantum non-destructive detection, can detect microwave photons without absorbing photons, and has broader application prospects in the field of quantum information processing.

[0003] Detection efficiency is a key indicator of microwave single-photon detectors, reflecting the ability of microwave single-photon detectors to respond to single photons. For microwave single-photon detection schemes based on controlling phase gates between microwave photons and superconducting quantum bits, the traditional detection efficiency measurement technology is to use weak coherent light to simulate a single-photon source and input it into a microwave single-photon detector to calculate the detection efficiency of the microwave single-photon detector. However, weak coherent light is not a true single-photon source, so there is a certain deviation between the detection efficiency of microwave single-photon detectors measured by traditional technology and the actual efficiency. Summary of the invention

[0004] Based on this, it is necessary to provide a microwave single-photon detector detection efficiency testing method, device and program product that can overcome the measurement deviation of microwave single-photon detector detection efficiency in traditional technology and improve the measurement accuracy of microwave single-photon detector detection efficiency in response to the above-mentioned technical problems.

[0005] In a first aspect, the present application provides a method for testing the detection efficiency of a microwave single-photon detector, comprising:

[0006] determining a corresponding relationship between a response rate of the microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave coherent signal;

[0007] converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number;

[0008] According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the detection efficiency of the microwave single photon detector.

[0009] In one embodiment, converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number includes:

[0010] Taking the quantum state of the input third microwave coherent signal as the coherent state, determining the photon number state basis form corresponding to the coherent state;

[0011] According to the average photon number and the corresponding relationship between the average photon number and the coherent state, the photon number state basis form corresponding to the coherent state is converted into a first superposition state of multiple photon number states;

[0012] The probabilities and values ​​of odd-numbered photon number states in a first superposition state of multiple photon number states are statistically analyzed to obtain a target superposition state of multiple photon number states.

[0013] In one embodiment, the quantum state of the input third microwave coherent signal is used as a coherent state, and the photon number state basis form corresponding to the coherent state is determined, including:

[0014] Obtaining the attenuated coherent state generated after the coherent state enters the microwave single-photon detector, and determining the photon number state basis form of the attenuated coherent state;

[0015] According to the average photon number and the corresponding relationship between the average photon number and the coherent state, the photon number state basis form corresponding to the coherent state is converted into a first superposition state of multiple photon number states, including:

[0016] According to the average photon number and the corresponding relationship between the average photon number and the coherent state, the photon number state basis form of the attenuated coherent state is converted into a first superposition state of multiple photon number states.

[0017] In one embodiment, according to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the detection efficiency of the microwave single photon detector, including:

[0018] According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the coupling efficiency and the internal detection efficiency of the microwave single photon detector;

[0019] The detection efficiency of the microwave single photon detector is determined based on the coupling efficiency and the internal detection efficiency of the microwave single photon detector.

[0020] In one embodiment, the third microwave coherent signal includes a third microwave coherent signal of a first power and a third microwave coherent signal of a second power, and determining a corresponding relationship between a response rate of the microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal, and the third microwave coherent signal includes:

[0021] Calibrate the average number of photons entering the microwave single-photon detector according to the third microwave coherent signal of the first power to obtain a corresponding relationship between the average number of photons and the microwave signal power;

[0022] Determining a corresponding relationship between a response rate of a microwave single-photon detector and a microwave signal power according to the first microwave coherent signal, the second microwave coherent signal and a third microwave coherent signal of the second power;

[0023] According to the corresponding relationship between the average number of photons and the microwave signal power and the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons is determined.

[0024] In one embodiment, determining the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power includes:

[0025] Controlling a microwave single-photon detector to perform detection according to the first microwave coherent signal, the second microwave coherent signal, and a third microwave coherent signal of the second power to obtain an output microwave signal;

[0026] determining a response state of the microwave single-photon detector according to the output microwave signal;

[0027] The corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power is determined according to the response state.

[0028] In one embodiment, controlling a microwave single-photon detector to perform detection according to the first microwave coherent signal, the second microwave coherent signal, and the third microwave coherent signal of the second power to obtain an output microwave signal includes:

[0029] inputting a third microwave coherent signal with a second power into the microwave photon detector to simulate the input of a microwave single photon;

[0030] controlling the microwave single-photon detector to respond to an odd number of photons and not to respond to an even number of photons according to the first microwave coherent signal;

[0031] The response state of the microwave single-photon detector is read according to the second microwave coherent signal.

[0032] In one embodiment, determining a response state of a microwave single-photon detector according to an output microwave signal comprises:

[0033] amplifying the output microwave signal to obtain an amplified output microwave signal;

[0034] Down-converting the amplified output microwave signal to obtain an intermediate frequency microwave signal;

[0035] The intermediate frequency microwave signal is converted into digital form to obtain the response state of the microwave single photon detector.

[0036] In a second aspect, the present application also provides a microwave single-photon detector detection efficiency test device, comprising:

[0037] A microwave signal generating component, used for generating a first microwave signal, a second microwave signal and a third microwave signal, and inputting the first microwave signal, the second microwave signal and the third microwave signal into a microwave single photon detector;

[0038] A microwave single-photon detector, used for detecting according to the first microwave signal, the second microwave signal and the third microwave signal to obtain an output microwave signal;

[0039] A signal analysis component is used to determine the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the output microwave signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave signal; according to the average number of photons, the quantum state of the third microwave signal is converted into a target superposition state of multiple photon number states; according to the target superposition state of multiple photon number states and a preset calculation relationship of the response rate of the microwave single-photon detector, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is fitted to obtain the detection efficiency of the microwave single-photon detector.

[0040] In one embodiment, the microwave signal generating component is further used to generate a third microwave signal of the first power, and input the third microwave signal of the first power into the microwave single photon detector;

[0041] The microwave single-photon detector is further used to calibrate the average number of photons entering the microwave single-photon detector according to the third microwave signal of the first power, so as to obtain a corresponding relationship between the average number of photons and the microwave signal power;

[0042] The microwave signal generating component is further used to generate a third microwave signal of a second power, and input the first microwave signal, the second microwave signal and the third microwave signal of the second power into the microwave single photon detector;

[0043] The microwave single-photon detector is also used to perform detection according to the first microwave signal, the second microwave signal and the third microwave signal of the second power to obtain an output microwave signal.

[0044] In one embodiment, the above device further comprises:

[0045] An amplifier group, used for amplifying the output microwave signal to obtain an amplified output microwave signal, and inputting the amplified output microwave signal into a signal demodulation component;

[0046] A signal demodulation component is used to perform down-conversion processing on the amplified output microwave signal to obtain an intermediate frequency microwave signal;

[0047] The signal analysis component is used to perform analog-to-digital conversion on the intermediate frequency microwave signal to obtain the response state of the microwave single photon detector; determine the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power according to the response state; determine the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector according to the corresponding relationship between the average number of photons and the microwave signal power and the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power.

[0048] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0049] determining a corresponding relationship between a response rate of the microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave coherent signal;

[0050] converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number;

[0051] According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the detection efficiency of the microwave single photon detector.

[0052] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0053] determining a corresponding relationship between a response rate of the microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave coherent signal;

[0054] converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number;

[0055] According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the detection efficiency of the microwave single photon detector.

[0056] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0057] determining a corresponding relationship between a response rate of the microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave coherent signal;

[0058] converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number;

[0059] According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the detection efficiency of the microwave single photon detector.

[0060] The above-mentioned microwave single-photon detector detection efficiency test method, device, computer equipment, storage medium and program product determine the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal, and then convert the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number, and then fit the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the target superposition state of multiple photon number states and the preset microwave single-photon detector response rate calculation relationship to obtain the detection efficiency of the microwave single-photon detector. By converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states, the quantum state of coherent light is expressed as a superposition of multiple photon number states, the multi-photon probability of coherent light is fully considered, the measurement deviation of the detection efficiency of the microwave single-photon detector in the traditional technology is overcome, and the measurement accuracy of the detection efficiency of the microwave single-photon detector is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 A schematic diagram of a flow chart of a method for testing detection efficiency of a microwave single-photon detector in one embodiment;

[0063] Figure 2 is a schematic diagram of a process of converting a quantum state of a third microwave coherent signal into a target superposition state of multiple photon number states according to an average photon number in one embodiment;

[0064] Figure 3 A schematic diagram of a flow chart for obtaining the detection efficiency of a microwave single photon detector by fitting the corresponding relationship between the response rate of a microwave single photon detector and the average number of photons entering the microwave single photon detector according to a target superposition state of multiple photon number states and a preset calculation relationship of the response rate of a microwave single photon detector in an embodiment;

[0065] Figure 4 It is a schematic diagram of a measured relationship curve and a fitting curve between the response rate of a microwave single-photon detector and the average number of photons entering the microwave single-photon detector in one embodiment;

[0066] Figure 5 A structural block diagram of a microwave single-photon detector detection efficiency testing device in one embodiment;

[0067] Figure 6 It is a structural block diagram of a microwave single photon detector detection efficiency testing device in another embodiment;

[0068] Figure 7 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0070] In an exemplary embodiment, Figure 1 As shown, a method for testing the detection efficiency of a microwave single-photon detector is provided, comprising the following steps 102 to 106. Among them:

[0071] Step 102, determining the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave coherent signal.

[0072] Among them, the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal are all microwave coherent optical pulse signals, that is, coherent light. The first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal are respectively used to control the response state of the microwave single photon detector, read the response state of the microwave single photon detector and simulate the microwave single photon input. The response rate of the microwave single photon detector refers to the ratio between the number of times the microwave single photon detector responds and the total number of signal inputs. The average number of photons entering the microwave single photon detector refers to the average number of photons of coherent light entering the microwave single photon detector within a preset time interval. The average number of photons is a key parameter used to describe the photon density received by the microwave single photon detector, and can be used to analyze the working state of the microwave single photon detector.

[0073] Optionally, after the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal are input into the microwave single-photon detector, the microwave single-photon detector starts to perform microwave single-photon detection to obtain an output microwave signal. The response rate of the microwave single-photon detector is determined according to the output microwave signal when coherent light with different average photon numbers is input into the microwave single-photon detector, that is, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is obtained. Since the third microwave coherent signal is used to simulate the input of a single photon, the average number of photons of the third microwave coherent signal is used as the average number of photons entering the microwave single-photon detector.

[0074] Exemplarily, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector can be a relationship curve between the response rate of the microwave single photon detector and the average number of photons in the microwave single photon detector.

[0075] Step 104: converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number.

[0076] The quantum state of the third microwave coherent signal refers to the state characteristics of the third microwave coherent signal at the quantum level. The photon number state is used to describe the number state of photons. The target superposition state of multiple photon number states refers to the superposition state of an odd number of photon number states represented by the average number of photons.

[0077] Optionally, the correspondence between the average number of photons and the quantum state is obtained, and according to the average number of photons of the third microwave coherent signal and the correspondence between the average number of photons and the quantum state, the quantum state of the third microwave coherent signal is converted into a target superposition state of multiple photon number states. The target superposition state of multiple photon number states is an unknown quantity. By converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states, the quantum state of the coherent light is expressed as a superposition of multiple photon number states, and the multi-photon probability of the coherent light is fully considered.

[0078] Step 106, according to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the detection efficiency of the microwave single photon detector.

[0079] The preset response rate calculation relationship of the microwave single photon detector refers to the calculation relationship between the superposition state of multiple photon number states and the response rate. The detection efficiency of the microwave single photon detector refers to the probability of successfully detecting an input photon.

[0080] Optionally, a preset response rate calculation relationship of a microwave single-photon detector is obtained. The response rate in the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is obtained, the response rate and the target superposition state of multiple photon number states are input into the response rate calculation relationship of the microwave single-photon detector, and the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is fitted to obtain the fitting parameter value in the response rate calculation relationship of the microwave single-photon detector, and the detection efficiency of the microwave single-photon detector is obtained according to the fitting parameter value.

[0081] The traditional microwave single-photon detection scheme uses weak coherent light to simulate a single-photon source, and regards the weak coherent light as a superposition state of a single photon and a vacuum state, and inputs it into a microwave single-photon detector to calculate the detection efficiency of the microwave single-photon detector. However, weak coherent light is not a true single-photon source. Coherent light has a multi-photon probability and cannot be strictly regarded as a superposition state of a single photon and a vacuum state. Therefore, there is a certain deviation between the detection efficiency of the microwave single-photon detector measured by traditional technology and the actual efficiency.

[0082] In the above-mentioned microwave single-photon detector detection efficiency test method, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is determined according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal, and then the quantum state of the third microwave coherent signal is converted into a target superposition state of multiple photon number states according to the average photon number, and then according to the target superposition state of multiple photon number states and the preset microwave single-photon detector response rate calculation relationship, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is fitted to obtain the detection efficiency of the microwave single-photon detector. By converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states, the quantum state of coherent light is expressed as a superposition of multiple photon number states, the multi-photon probability of coherent light is fully considered, the measurement deviation of the detection efficiency of the microwave single-photon detector in the traditional technology is overcome, and the measurement accuracy of the detection efficiency of the microwave single-photon detector is improved.

[0083] In an exemplary embodiment, Figure 2 As shown, step 104, converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number, includes the following steps:

[0084] Step 202: Taking the quantum state of the input third microwave coherent signal as the coherent state, determining the photon number state basis form corresponding to the coherent state.

[0085] Step 204: According to the average photon number and the corresponding relationship between the average photon number and the coherent state, the photon number state basis form corresponding to the coherent state is converted into a first superposition state of multiple photon number states.

[0086] Step 206 , statistically analyzing the probabilities and values ​​of odd-numbered photon number states in the first superposition state of the plurality of photon number states to obtain a target superposition state of the plurality of photon number states.

[0087] Optionally, the quantum state of the input third microwave coherent signal is recorded as a coherent state, and the photon number state basis form corresponding to the coherent state is determined. The coherent state refers to a quantum state with a certain phase relationship. The photon number state basis form corresponding to the coherent state refers to the expansion form of the coherent state on the photon number state basis, which is expressed as:

[0088]

[0089] in, represents the coherent state, is a complex number that describes the amplitude and phase of the coherent state, represents the photon number state, Represents the number of photons corresponding to the photon number state.

[0090] Afterwards, the correspondence between the average number of photons and the coherent state is obtained, and according to the correspondence between the average number of photons and the coherent state and the average number of photons of the third microwave coherent signal, the photon number state basis form corresponding to the coherent state is converted into a first superposition state of multiple photon number states. The first superposition state of multiple photon number states refers to a superposition state of multiple photon number states represented by the average number of photons.

[0091] Since the coherent state is a superposition state from 0 photons to an infinite number of photon states, and since microwave single-photon detectors only respond to odd number of photons and have no response to even number of photons, the probabilities and values ​​of odd number of photon states in the first superposition state of multiple photon number states are statistically analyzed to obtain the target superposition state of multiple photon number states.

[0092] In this embodiment, the quantum state of the input third microwave coherent signal is taken as the coherent state, and the basis form of the photon number state corresponding to the coherent state is determined, so that the quantum state of the coherent light can be expressed as the superposition of multiple photon number states. According to the average number of photons and the corresponding relationship between the average number of photons and the coherent state, the basis form of the photon number state corresponding to the coherent state is converted into the first superposition state of multiple photon number states, so that the superposition state of multiple photon number states can be represented by the known average number of photons, which is convenient for the subsequent calculation of the detection efficiency of the microwave single-photon detector. In the test process of the detection efficiency of the microwave single-photon detector, the probability and value of the odd number of photon number states in the first superposition state of multiple photon number states are statistically analyzed, considering that the microwave single-photon detector only responds to odd number of photons, that is, considering the influence of multi-photon events on the detector response, which can achieve more accurate microwave single-photon detector detection efficiency measurement.

[0093] In an optional manner of the above embodiment, step 202, taking the quantum state of the input third microwave coherent signal as the coherent state, determining the photon number state basis form corresponding to the coherent state, including: obtaining the attenuated coherent state generated after the coherent state enters the microwave single-photon detector, and determining the photon number state basis form of the attenuated coherent state; step 204, converting the photon number state basis form corresponding to the coherent state into a first superposition state of multiple photon number states according to the average photon number and the corresponding relationship between the average photon number and the coherent state, including: converting the photon number state basis form of the attenuated coherent state into a first superposition state of multiple photon number states according to the average photon number and the corresponding relationship between the average photon number and the coherent state.

[0094] Optionally, when the coherent state enters the microwave single-photon detector, it is affected by the coupling efficiency and attenuated to become the attenuated coherent state. Therefore, the photon number state basis form corresponding to the finally determined coherent state is the photon number state basis form of the attenuated coherent state. The photon number state basis form of the attenuated coherent state can be expressed as:

[0095]

[0096] in, represents the coherent state after decay, It represents the coupling efficiency of microwave single photon into microwave single photon detector. The coupling efficiency of microwave single photon into microwave single photon detector is an unknown quantity.

[0097] After that, the corresponding relationship between the average number of photons and the coherent state is obtained as follows:

[0098]

[0099] in, Represents the average photon number of the third microwave coherent signal.

[0100] According to the corresponding relationship between the average number of photons and the coherent state, the photon number state basis form of the attenuated coherent state is converted into the first superposition state of multiple photon number states, as shown below:

[0101]

[0102] in, Represents the first superposition state of multiple photon number states.

[0103] Furthermore, the probability and value of the odd number of photon states in the first superposition state of the multiple photon number states are counted to obtain the target superposition state of the multiple photon number states. The target superposition state of the multiple photon number states is as follows:

[0104]

[0105] in, It represents the probability and value of an odd number of photon states, that is, the target superposition state of multiple photon states. k represents the symbol used for counting, indicating the situation of accumulating from 0 to infinity. For example, k=0 corresponds to 1 photon, k=1 corresponds to 3 photons, and k=2 corresponds to 5 photons.

[0106] In this embodiment, after the coherent state enters the microwave single-photon detector, the attenuated coherent state is generated, and the photon number state basis form of the attenuated coherent state is determined. The influence of the internal structure of the microwave single-photon detector on the coherent state is taken into account, which is beneficial to improving the accuracy of the detection efficiency of the microwave single-photon detector.

[0107] In an exemplary embodiment, Figure 3 As shown, step 106, according to the target superposition state of multiple photon number states and the preset microwave single photon detector response rate calculation relationship, fit the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector to obtain the detection efficiency of the microwave single photon detector, includes the following steps:

[0108] Step 302, according to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the coupling efficiency and the internal detection efficiency of the microwave single photon detector.

[0109] Step 304 , determining the detection efficiency of the microwave single photon detector according to the coupling efficiency and the internal detection efficiency of the microwave single photon detector.

[0110] Optionally, a preset response rate calculation relationship of a microwave single-photon detector is obtained, and the response rate calculation relationship of the microwave single-photon detector includes fitting parameters, and the fitting parameters include the internal detection efficiency, coupling efficiency and dark count probability of the microwave single-photon detector. Among them, the internal detection efficiency refers to the ability of the microwave single-photon detector to successfully convert photons into measurable signals, such as current, pulses, etc. after capturing them, reflecting the effectiveness of the photoelectric conversion process inside the detector. The coupling efficiency refers to the coupling efficiency of microwave single photons from an external transmission system into the microwave single-photon detector. The dark count probability refers to the probability of false triggering of the microwave single-photon detector within a preset time or in a single measurement cycle.

[0111] Furthermore, the response rate of the microwave single-photon detector is calculated as the product of the target superposition state of multiple photon number states and the internal detection efficiency of the microwave single-photon detector, plus the dark count probability.

[0112] The target superposition state of multiple photon number states and the response rate of the microwave single photon detector are input into the preset microwave single photon detector response rate calculation relationship, and the relationship curve between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the parameter values ​​corresponding to the fitting parameters, namely, the internal detection efficiency of the microwave single photon detector, the coupling efficiency of microwave single photons entering the microwave single photon detector, and the dark count rate. The internal detection efficiency of the microwave single photon detector and the coupling efficiency of microwave single photons entering the microwave single photon detector are multiplied to obtain the detection efficiency of the microwave single photon detector.

[0113] See also Figure 4, are the measured relationship curve and fitting curve of the microwave single photon detector response rate and the average number of photons entering the microwave single photon detector, where the circle is the measured relationship curve, the solid line is the fitting curve, and the dotted line is the tangent of the fitting curve at zero point, and its slope represents the detection efficiency of the microwave single photon detector. It can be concluded that with the increase of the average number of photons in the microwave single photon detector, the response rate of the microwave single photon detector increases nonlinearly, and the fitting curve can fit this change law well, thereby obtaining the detection efficiency of the microwave single photon detector.

[0114] In this embodiment, since the preset response rate calculation relationship of the microwave single-photon detector fully considers the multi-photon probability of measuring coherent light and the impact of multi-photon events on the detector response, according to the target superposition state of multiple photon number states and the preset response rate calculation relationship of the microwave single-photon detector, the correspondence between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is fitted, which can achieve more accurate detection efficiency measurement of the microwave single-photon detector.

[0115] In an exemplary embodiment, the third microwave coherent signal includes a third microwave coherent signal of a first power and a third microwave coherent signal of a second power, and determining a correspondence between a response rate of a microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal includes: calibrating the average number of photons entering the microwave single-photon detector according to the third microwave coherent signal of the first power to obtain a correspondence between the average number of photons and the microwave signal power; determining a correspondence between the response rate of the microwave single-photon detector and the microwave signal power according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power; determining a correspondence between the response rate of the microwave single-photon detector and the average number of photons according to the correspondence between the average number of photons and the microwave signal power and the correspondence between the response rate of the microwave single-photon detector and the microwave signal power.

[0116] Among them, the third microwave coherent signal includes a third microwave coherent signal of a first power and a third microwave coherent signal of a second power. The first power and the second power both include multiple different powers. The first power and the second power may be the same or different. The third microwave coherent signal of the first power and the third microwave coherent signal of the second power have the same frequency. The third microwave coherent signal of the first power is used to calibrate the average number of photons entering the microwave single-photon detector. The third microwave coherent signal of the second power is used to determine the correspondence between the response rate of the microwave single-photon detector and the microwave signal power.

[0117] Optionally, a third microwave coherent signal of different power is input, that is, the third microwave coherent signal of the first power enters the microwave single-photon detector, and the average number of photons entering the microwave single-photon detector is calibrated, thereby establishing a corresponding relationship between the microwave signal power of the third microwave coherent signal and the average number of photons. Usually, the microwave signal power of a microwave signal is easy to determine, and the microwave source can be directly displayed, while the average number of photons entering the microwave single-photon detector is unknown. By establishing a corresponding relationship between the microwave signal power of the third microwave coherent signal and the average number of photons, the average number of photons can be determined by the microwave signal power.

[0118] Alternatively, the average photon number calibration can be implemented based on a variety of physical principles well known to those skilled in the art. For example, when different average photon numbers are input, the frequency and coherence time of the superconducting quantum bit in the microwave single-photon detector will change. The relationship between the average photon number and the change can be accurately derived through a theoretical model. It is only necessary to measure the change (frequency and coherence time) to determine the input average photon number according to the theoretical model.

[0119] The first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power are input to the microwave single photon detector, so that the microwave single photon detector starts microwave detection, thereby determining the response rate of the microwave single photon detector when the third microwave coherent signal of different powers, i.e., the third microwave coherent signal of the second power, is input as the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power. Combined with the corresponding relationship between the average number of photons and the microwave signal power, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons is obtained.

[0120] In this embodiment, the average number of photons entering the microwave single-photon detector is calibrated according to the third microwave coherent signal of the first power to establish a corresponding relationship between the microwave signal power of the third microwave coherent signal and the average number of photons, so as to determine the average number of photons by the microwave signal power. Afterwards, the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power can be determined according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power. Combined with the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power and the corresponding relationship between the average number of photons and the microwave signal power, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons can be accurately derived.

[0121] In an optional manner in the above embodiment, the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power is determined according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power, including: controlling the microwave single-photon detector to perform detection according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power to obtain an output microwave signal; determining the response state of the microwave single-photon detector according to the output microwave signal; and determining the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power according to the response state.

[0122] Optionally, a first microwave coherent signal and a second microwave coherent signal are input to a microwave single-photon detector, the microwave single-photon detector is controlled to start according to the first microwave coherent signal and the second microwave coherent signal, and then a third microwave coherent signal with a different power, i.e., a third microwave coherent signal with the second power, is input to the microwave single-photon detector to start microwave single-photon detection and obtain an output microwave signal.

[0123] The response state of the microwave single photon detector is determined according to the output microwave signal. The response state refers to whether the microwave single photon detector responds, including two states: response and non-response. Then, the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power is determined according to the response state.

[0124] For example, the third microwave coherent signal of the same power is repeatedly input multiple times, and each time whether the microwave single photon detector responds is recorded, and the ratio between the number of times the microwave single photon detector responds and the total number of repetitions is counted, which is the response rate. Then, the power of the third microwave coherent signal is changed, and the above process is repeated to determine the response rate of the microwave single photon detector when the third microwave coherent signal of different powers is input, that is, the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power.

[0125] In this embodiment, the third microwave coherent signal is used to simulate microwave single photon input, and the first microwave coherent signal and the second microwave coherent signal are respectively used to control the response state of the microwave single photon detector and read the response state of the microwave single photon detector. According to the response state, the corresponding relationship between the response rate of the microwave single photon detector and the microwave signal power can be accurately obtained.

[0126] Furthermore, the microwave single-photon detector is controlled to perform detection according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power to obtain an output microwave signal, including: inputting the third microwave coherent signal of the second power to the microwave photon detector to simulate the input of microwave single photons; controlling the microwave single-photon detector to respond to an odd number of photons and not respond to an even number of photons according to the first microwave coherent signal; and reading the response state of the microwave single-photon detector according to the second microwave coherent signal.

[0127] Specifically, by inputting the third microwave coherent signal of the second power to the microwave photon detector, the input of simulated microwave single photons is realized. Under the control of the first microwave coherent signal, the microwave single photon detector can respond to the odd number of photons in the third microwave coherent signal of the second power, and has no response to the even number of photons. The response state of the microwave single photon detector is obtained through the second microwave coherent signal, and the microwave single photon detector can generate an output microwave signal according to the second microwave coherent signal.

[0128] Since the microwave single photon detector only responds to an odd number of photons in the third microwave coherent signal of the second power, the response rate calculation relationship of the microwave single photon detector can be shown as follows:

[0129]

[0130] Where P represents the response rate of the microwave single-photon detector, represents the internal detection efficiency of the microwave single-photon detector, represents the probability and value of an odd number of photons, represents the dark count probability of the microwave single photon detector, , and All are fitting parameters, detection efficiency .

[0131] In this embodiment, the microwave single-photon detector is controlled to respond only to an odd number of photons by the first microwave coherent signal, which fully considers the impact of multi-photon events on the microwave single-photon detector and is conducive to more accurate measurement of the detection efficiency of the microwave single-photon detector.

[0132] Furthermore, the response state of the microwave single-photon detector is determined according to the output microwave signal, including: amplifying the output microwave signal to obtain an amplified output microwave signal; down-converting the amplified output microwave signal to obtain an intermediate frequency microwave signal; and performing analog-to-digital conversion on the intermediate frequency microwave signal to obtain the response state of the microwave single-photon detector.

[0133] Optionally, the output microwave signal is amplified by an amplifier group to obtain an amplified output microwave signal. The amplified output microwave signal is down-converted by a signal demodulation component to obtain an intermediate frequency microwave signal. The intermediate frequency microwave signal is subjected to analog-to-digital conversion and digital signal processing by a signal analysis component to obtain a response state of a microwave single photon detector. The digital signal processing may be to extract a pulse feature of a digital signal, and identify the response state of the microwave single photon detector according to the pulse feature by a classifier.

[0134] In this embodiment, the output microwave signal is amplified to increase the power of the output microwave signal and enhance the signal quality. Since the subsequent signal analysis component cannot directly collect the microwave signal (the frequency is too high), the amplified output microwave signal is down-converted to achieve subsequent analog-to-digital conversion and signal analysis.

[0135] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0136] Based on the same inventive concept, the embodiment of the present application also provides a microwave single photon detector detection efficiency test device for implementing the microwave single photon detector detection efficiency test method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more microwave single photon detector detection efficiency test device embodiments provided below can refer to the limitations of the microwave single photon detector detection efficiency test method above, and will not be repeated here.

[0137] In an exemplary embodiment, Figure 5 As shown, a microwave single-photon detector detection efficiency testing device is provided, including: a microwave signal generating component 100, a microwave single-photon detector 200, an amplifier group 300, a signal demodulation component 400 and a signal analysis component 500.

[0138] The microwave signal generating component 100 is used to generate a first microwave coherent signal, a second microwave coherent signal and a third microwave coherent signal, and input the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal to the microwave single photon detector 200 .

[0139] The microwave single-photon detector 200 is used to perform detection according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal to obtain an output microwave signal.

[0140] The signal analysis component 500 is used to determine the corresponding relationship between the response rate of the microwave single-photon detector 200 and the average number of photons entering the microwave single-photon detector 200 according to the output microwave signal; the average number of photons entering the microwave single-photon detector 200 is the average number of photons of the third microwave coherent signal; according to the average number of photons, the quantum state of the third microwave coherent signal is converted into a target superposition state of multiple photon number states; according to the target superposition state of multiple photon number states and a preset response rate calculation relationship of the microwave single-photon detector, the corresponding relationship between the response rate of the microwave single-photon detector 200 and the average number of photons entering the microwave single-photon detector 200 is fitted to obtain the detection efficiency of the microwave single-photon detector 200.

[0141] Optionally, the microwave signal generating component includes a first frequency mixing unit, a second frequency mixing unit and a third frequency mixing unit, wherein the first frequency mixing unit, the second frequency mixing unit and the third frequency mixing unit are respectively used to generate a first microwave coherent signal, a second microwave coherent signal and a third microwave coherent signal, and input the generated microwave signals to the microwave single photon detector 200. The microwave single photon detector 200 is placed on a 10mK temperature platform of a dilution refrigerator. The first frequency mixing unit, the second frequency mixing unit and the third frequency mixing unit each include a microwave source, a mixer and an arbitrary waveform generator.

[0142] Further, the first frequency mixing unit includes a first microwave source, a first mixer and a first waveform generator, the second frequency mixing unit includes a second microwave source, a second mixer and a second waveform generator, and the third frequency mixing unit includes a third microwave source, a third mixer and a third waveform generator. For example, the first mixer, the second mixer and the third mixer can be in-phase orthogonal mixers. The first microwave source outputs a first continuous microwave signal, the first waveform generator outputs two first low-frequency pulse signals, the first continuous microwave signal and the two first low-frequency pulse signals are mixed in the first mixer to obtain a first microwave coherent signal. The second microwave source outputs a second continuous microwave signal, the second waveform generator outputs two second low-frequency pulse signals, the second continuous microwave signal and the two second low-frequency pulse signals are mixed in the second mixer to obtain a second microwave coherent signal. The third microwave source outputs a third continuous microwave signal, the third waveform generator outputs two third low-frequency pulse signals, the third continuous microwave signal and the two third low-frequency pulse signals are mixed in the third mixer to obtain a third microwave coherent signal.

[0143] The specific processing procedures of the microwave single photon detector 200 and the signal analysis component 500 can be found in the above-mentioned definition of the microwave single photon detector detection efficiency test method, which will not be repeated here.

[0144] In this embodiment, the signal analysis component 500 is used to determine the corresponding relationship between the response rate of the microwave single photon detector 200 and the average number of photons entering the microwave single photon detector 200 according to the output microwave signal, and then convert the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number, and then fit the corresponding relationship between the response rate of the microwave single photon detector 200 and the average number of photons entering the microwave single photon detector 200 according to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector to obtain the detection efficiency of the microwave single photon detector 200. By converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states, the quantum state of the coherent light is expressed as the superposition of multiple photon number states, the multi-photon probability of the coherent light is fully considered, the measurement deviation of the detection efficiency of the microwave single photon detector in the traditional technology is overcome, and the measurement accuracy of the detection efficiency of the microwave single photon detector is improved.

[0145] In an exemplary embodiment, the microwave signal generating component 100 is further configured to generate a third microwave coherent signal of the first power, and input the third microwave coherent signal of the first power to the microwave single photon detector 200 .

[0146] The microwave single-photon detector 200 is further used to calibrate the average number of photons entering the microwave single-photon detector 200 according to the third microwave coherent signal of the first power, so as to obtain a corresponding relationship between the average number of photons and the microwave signal power.

[0147] The microwave signal generating component 100 is further used to generate a third microwave coherent signal of the second power, and input the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power to the microwave single photon detector 200 .

[0148] The microwave single-photon detector 200 is further used to perform detection according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power to obtain an output microwave signal.

[0149] In an exemplary embodiment, the microwave signal generating component 100 is further used to input a third microwave coherent signal with a second power to the microwave photon detector 200 to simulate the input of a microwave single photon.

[0150] The microwave single-photon detector 200 is also used to respond to an odd number of photons and not respond to an even number of photons under the control of the first microwave coherent signal; and to read the response state of the microwave single-photon detector 200 according to the second microwave coherent signal.

[0151] In an exemplary embodiment, please refer to Figure 5The amplifier group 300 is used to amplify the output microwave signal to obtain an amplified output microwave signal, and input the amplified output microwave signal to the signal demodulation component 400.

[0152] The signal demodulation component 400 is used to perform down-conversion processing on the amplified output microwave signal to obtain an intermediate frequency microwave signal.

[0153] The signal analysis component 500 is used to perform analog-to-digital conversion on the intermediate frequency microwave signal to obtain the response state of the microwave single photon detector 200; determine the corresponding relationship between the response rate of the microwave single photon detector 200 and the microwave signal power according to the response state; determine the corresponding relationship between the response rate of the microwave single photon detector 200 and the average number of photons entering the microwave single photon detector 200 according to the corresponding relationship between the average number of photons and the microwave signal power and the corresponding relationship between the response rate of the microwave single photon detector 200 and the microwave signal power.

[0154] Exemplarily, the amplifier group 300 may include at least one amplifier, such as the amplifier group 300 may include a Josephson parametric amplifier, a low temperature low noise amplifier, and a room temperature low noise amplifier. The signal demodulation component 400 may include a microwave source, a mixer, and a filter. The signal analysis component 500 may include an amplifier, a filter, an analog-to-digital converter, and a terminal.

[0155] In an exemplary embodiment, the signal analysis component 500 is also used to take the quantum state of the input third microwave coherent signal as a coherent state, determine the basis form of the photon number state corresponding to the coherent state; convert the basis form of the photon number state corresponding to the coherent state into a first superposition state of multiple photon number states according to the average number of photons and the corresponding relationship between the average number of photons and the coherent state; and perform statistics on the probabilities and values ​​of odd-numbered photon number states in the first superposition state of multiple photon number states to obtain a target superposition state of multiple photon number states.

[0156] In an exemplary embodiment, the signal analysis component 500 is also used to obtain the attenuated coherent state generated after the coherent state enters the microwave single-photon detector 200, and determine the photon number state basis form of the attenuated coherent state; according to the average number of photons and the corresponding relationship between the average number of photons and the coherent state, the photon number state basis form of the attenuated coherent state is converted into a first superposition state of multiple photon number states.

[0157] In an exemplary embodiment, the signal analysis component 500 is also used to fit the corresponding relationship between the response rate of the microwave single photon detector 200 and the average number of photons entering the microwave single photon detector 200 according to the target superposition state of multiple photon number states and a preset microwave single photon detector response rate calculation relationship, so as to obtain the coupling efficiency and the internal detection efficiency of the microwave single photon detector 200; and determine the detection efficiency of the microwave single photon detector 200 according to the coupling efficiency and the internal detection efficiency of the microwave single photon detector 200.

[0158] In an exemplary embodiment, the signal analysis component 500 is also used to determine the response state of the microwave single photon detector 200 based on the output microwave signal; determine the corresponding relationship between the response rate of the microwave single photon detector 200 and the microwave signal power based on the response state; determine the corresponding relationship between the response rate of the microwave single photon detector 200 and the average number of photons based on the corresponding relationship between the average number of photons and the microwave signal power and the corresponding relationship between the response rate of the microwave single photon detector 200 and the microwave signal power.

[0159] In another exemplary embodiment, Figure 6 As shown, a microwave single-photon detector detection efficiency test device is provided, wherein a microwave signal generating component 100 includes a first frequency mixing unit, a second frequency mixing unit and a third frequency mixing unit, the first frequency mixing unit includes a first microwave source 1011, a first frequency mixer 1012 and a first waveform generator 1013, the second frequency mixing unit includes a second microwave source 1021, a second frequency mixer 1022 and a second waveform generator 1023, and the third frequency mixing unit includes a third microwave source 1031, a third frequency mixer 1032 and a third waveform generator 1033. The first microwave source 1011 outputs a first continuous microwave signal, the first waveform generator 1013 outputs two first low-frequency pulse signals, the first continuous microwave signal and the two first low-frequency pulse signals are mixed in the first frequency mixer 1012 to obtain a first microwave coherent signal. The second microwave source 1021 outputs a second continuous microwave signal, the second waveform generator 1023 outputs two second low-frequency pulse signals, the second continuous microwave signal and the two second low-frequency pulse signals are mixed in the second mixer 1022 to obtain a second microwave coherent signal. The third microwave source 1031 outputs a third continuous microwave signal, the third waveform generator 1033 outputs two third low-frequency pulse signals, the third continuous microwave signal and the two third low-frequency pulse signals are mixed in the third mixer 1032 to obtain a third microwave coherent signal.

[0160] The first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal are commonly input to the microwave single-photon detector 200 .

[0161] The amplifier group 300 includes a Josephson parameter amplifier 301, a low temperature low noise amplifier 302 and a room temperature low noise amplifier 303. The output microwave signal of the microwave single photon detector is amplified in the Josephson parameter amplifier 301, the low temperature low noise amplifier 302 and the room temperature low noise amplifier 303 in sequence. The Josephson parameter amplifier 301 is placed on the 10mK temperature platform of the dilution refrigerator, the low temperature low noise amplifier 302 is placed on the 4K temperature platform of the dilution refrigerator, and the room temperature low noise amplifier 303 is placed at room temperature.

[0162] The signal demodulation component 400 includes a microwave source 401, a mixer 402 and a low-pass filter 403. The output microwave signal enters the signal demodulation component 400 after being amplified. The microwave source 401 outputs a continuous local oscillator microwave signal, which is mixed with the amplified output microwave signal in the mixer 402. The mixed signal is filtered by the low-pass filter 403 to obtain an intermediate frequency microwave signal.

[0163] The signal analysis component 500 includes an intermediate frequency amplifier 501, an analog-to-digital converter 502, and a terminal 503. The intermediate frequency microwave signal enters the signal acquisition component 500. The intermediate frequency microwave signal is first amplified in the intermediate frequency amplifier 501, and then converted from an analog signal to a digital signal in the analog-to-digital converter 502, and the digital signal is then transmitted to the terminal 503. The digital signal is subjected to information processing and analysis in the terminal 503 to obtain the response state of the microwave single photon detector 200.

[0164] Each component in the above-mentioned microwave single-photon detector detection efficiency test device can be implemented in whole or in part by software, hardware and their combination. The above-mentioned components can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of the above-mentioned components.

[0165] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Figure 7As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data such as a preset response rate calculation relationship of a microwave single-photon detector, a corresponding relationship between the response rate of a microwave single-photon detector and the average number of photons entering the microwave single-photon detector. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for testing the detection efficiency of a microwave single-photon detector is implemented.

[0166] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0167] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0168] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0169] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0170] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0171] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for testing the detection efficiency of a microwave single-photon detector, characterized in that: The method comprises: Determining a corresponding relationship between a response rate of the microwave single-photon detector and an average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal, and the third microwave coherent signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave coherent signal; Converting the quantum state of the third microwave coherent signal into a target superposition state of multiple photon number states according to the average photon number; According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single-photon detector, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is fitted to obtain the detection efficiency of the microwave single-photon detector.

2. The method according to claim 1, characterized in that: The step of converting the quantum state of the third microwave coherent signal into a target superposition state of a plurality of photon number states according to the average number of photons comprises: Taking the quantum state of the input third microwave coherent signal as a coherent state, and determining a photon number state basis form corresponding to the coherent state; According to the average photon number and the corresponding relationship between the average photon number and the coherent state, converting the photon number state basis form corresponding to the coherent state into a first superposition state of multiple photon number states; The probabilities and values ​​of odd-numbered photon number states in a first superposition state of multiple photon number states are statistically analyzed to obtain a target superposition state of multiple photon number states.

3. The method according to claim 2, characterized in that The step of taking the quantum state of the input third microwave coherent signal as a coherent state and determining the photon number state basis form corresponding to the coherent state comprises: Acquiring a coherent state after the coherent state enters the microwave single-photon detector, and determining the photon number state basis form of the coherent state after the decay; According to the average photon number and the corresponding relationship between the average photon number and the coherent state, converting the photon number state basis form corresponding to the coherent state into a first superposition state of multiple photon number states includes: According to the average photon number and the corresponding relationship between the average photon number and the coherent state, the photon number state basis form of the attenuated coherent state is converted into a first superposition state of multiple photon number states.

4. The method according to claim 1, characterized in that: The method of fitting the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the target superposition state of multiple photon number states and the preset response rate calculation relationship of the microwave single-photon detector to obtain the detection efficiency of the microwave single-photon detector includes: According to the target superposition state of multiple photon number states and the preset calculation relationship of the response rate of the microwave single photon detector, the corresponding relationship between the response rate of the microwave single photon detector and the average number of photons entering the microwave single photon detector is fitted to obtain the coupling efficiency and the internal detection efficiency of the microwave single photon detector; The detection efficiency of the microwave single-photon detector is determined according to the coupling efficiency and the internal detection efficiency of the microwave single-photon detector.

5. The method according to claim 1, characterized in that The third microwave coherent signal includes a third microwave coherent signal of a first power and a third microwave coherent signal of a second power, and determining the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the first microwave coherent signal, the second microwave coherent signal, and the third microwave coherent signal includes: Calibrate the average number of photons entering the microwave single-photon detector according to the third microwave coherent signal of the first power to obtain a corresponding relationship between the average number of photons and the microwave signal power; Determining a corresponding relationship between a response rate of a microwave single-photon detector and a microwave signal power according to the first microwave coherent signal, the second microwave coherent signal and a third microwave coherent signal of the second power; The corresponding relationship between the average number of photons and the microwave signal power and the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power is determined.

6. The method according to claim 5, characterized in that Determining the corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power includes: Controlling the microwave single-photon detector to perform detection according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power to obtain an output microwave signal; determining a response state of the microwave single-photon detector according to the output microwave signal; The corresponding relationship between the response rate of the microwave single-photon detector and the microwave signal power is determined according to the response state.

7. The method according to claim 6, characterized in that The step of controlling the microwave single-photon detector to perform detection according to the first microwave coherent signal, the second microwave coherent signal and the third microwave coherent signal of the second power to obtain an output microwave signal comprises: Inputting a third microwave coherent signal of the second power into the microwave photon detector to simulate an input of a microwave single photon; Controlling the microwave single-photon detector to respond to an odd number of photons and not respond to an even number of photons according to the first microwave coherent signal; The response state of the microwave single-photon detector is read according to the second microwave coherent signal.

8. The method according to claim 6, characterized in that Determining the response state of the microwave single-photon detector according to the output microwave signal comprises: amplifying the output microwave signal to obtain an amplified output microwave signal; Performing down-conversion processing on the amplified output microwave signal to obtain an intermediate frequency microwave signal; The intermediate frequency microwave signal is subjected to analog-to-digital conversion to obtain a response state of the microwave single-photon detector.

9. A microwave single-photon detector detection efficiency test device, characterized in that: The device comprises: A microwave signal generating component, used for generating a first microwave signal, a second microwave signal and a third microwave signal, and inputting the first microwave signal, the second microwave signal and the third microwave signal into a microwave single photon detector; A microwave single-photon detector, used for detecting according to the first microwave signal, the second microwave signal and the third microwave signal to obtain an output microwave signal; A signal analysis component is used to determine the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector according to the output microwave signal; the average number of photons entering the microwave single-photon detector is the average number of photons of the third microwave signal; according to the average number of photons, the quantum state of the third microwave signal is converted into a target superposition state of multiple photon number states; according to the target superposition state of multiple photon number states and a preset calculation relationship of the response rate of the microwave single-photon detector, the corresponding relationship between the response rate of the microwave single-photon detector and the average number of photons entering the microwave single-photon detector is fitted to obtain the detection efficiency of the microwave single-photon detector.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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