Quantum bit reading parameter calibration method and device, equipment and storage medium

Abstract

The invention discloses a quantum bit reading parameter calibration method and device, equipment and a storage medium, and relates to the technical field of quantum computing, and the method comprises the steps: collecting a reading feedback signal according to different data collection durations under each alternative quantum bit reading frequency, and carrying out the calibration of a quantum bit reading parameter based on the collected reading feedback signal; and determining the reading fidelity in different data acquisition durations under each alternative quantum bit reading frequency. Therefore, the quantum bit reading frequency and the data acquisition duration can be comprehensively considered based on the determined reading fidelity. After the alternative quantum bit reading frequency and the data acquisition duration corresponding to the maximum reading fidelity are used as the calibrated quantum bit reading parameter, the calibrated quantum bit reading parameter can be a relatively excellent parameter, so that the purpose of improving the accuracy of the quantum bit reading parameter is achieved; and thus, the read quantum bit state is more accurate.

Description

Technical Field

[0001] The present application relates to the field of quantum computing technology, and in particular to a calibration method, device, equipment and storage medium for quantum bit reading parameters. Background Art

[0002] Quantum computing is a new computing model that follows the laws of quantum mechanics to control quantum information units for computing. The qubit is the basic unit of quantum computing. Unlike the classical bit, which can only take the value 0 or 1, the qubit can be in the |0> state or the |1> state, as well as the superposition state of |0> and |1>. This superposition state gives quantum computers greater potential in processing information.

[0003] After the quantum computation is completed, the state of the quantum bit needs to be read to determine the final computation result. At present, in some technologies, due to the inaccurate setting of the quantum bit reading parameters, the read quantum bit state is not accurate enough, which in turn affects the accuracy of the quantum computation result. Summary of the invention

[0004] The present application provides a method for calibrating quantum bit reading parameters, a device for calibrating quantum bit reading parameters, an electronic device, a computer-readable storage medium and a computer program product, so as to at least solve the problem that the quantum bit state read in the related art is not accurate enough.

[0005] The present application provides a method for calibrating a quantum bit reading parameter, comprising: Obtaining multiple candidate quantum bit reading frequencies; For any of the candidate quantum bit reading frequencies, perform quantum bit state reading according to the candidate quantum bit reading frequency, and collect read feedback signals at the candidate quantum bit reading frequency according to a plurality of different data collection durations; For any of the candidate quantum bit reading frequencies, based on a read feedback signal collected at the candidate quantum bit reading frequency, determining the read fidelity within each of the data collection durations; In the obtained reading fidelity, the candidate quantum bit reading frequency and data acquisition duration corresponding to the maximum reading fidelity are used as calibrated quantum bit reading parameters.

[0006] The present application also provides a calibration device for quantum bit reading parameters, including: A data acquisition module, used to obtain multiple candidate quantum bit reading frequencies; A signal acquisition module, for performing quantum bit state reading according to any of the candidate quantum bit reading frequencies, and collecting a read feedback signal at the candidate quantum bit reading frequency according to a plurality of different data acquisition durations; A fidelity determination module, for determining, for any of the candidate quantum bit reading frequencies, the reading fidelity within each of the data collection durations based on a read feedback signal collected at the candidate quantum bit reading frequency; The data screening module is used to use the candidate quantum bit reading frequency and data collection time corresponding to the maximum reading fidelity as the calibrated quantum bit reading parameters in the obtained reading fidelity.

[0007] The present application also provides an electronic device, comprising: a memory for storing a computer program; and a processor for implementing the steps of any one of the above-mentioned calibration methods when executing the computer program.

[0008] The present application also provides a computer-readable storage medium, in which a computer program is stored, wherein when the computer program is executed by a processor, the steps of any of the above-mentioned marking methods are implemented.

[0009] The present application also provides a computer program product, including a computer program, which implements the steps of any of the above-mentioned marking methods when executed by a processor.

[0010] Through this application, at each candidate quantum bit reading frequency, the reading feedback signal is collected according to different data collection durations, and based on the collected reading feedback signal, the reading fidelity within different data collection durations at each candidate quantum bit reading frequency is determined. In this way, the quantum bit reading frequency and data collection duration can be comprehensively considered based on the determined reading fidelity. When the candidate quantum bit reading frequency and data collection duration corresponding to the maximum reading fidelity are used as the calibrated quantum bit reading parameters, the calibrated quantum bit reading parameters can be made relatively optimal parameters, achieving the purpose of improving the accuracy of the quantum bit reading parameters, and thus making the read quantum bit state more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0012] Figure 1 Schematic diagram of the quantum bit state reading system in some technologies; Figure 2 Schematic diagram of the transmission characteristics of the planar waveguide resonant cavity under different quantum bit states; Figure 3 A schematic diagram of a flow chart of a calibration method provided for some embodiments of the present application; Figure 4 A schematic diagram of scattered distribution of signal characteristic values ​​provided for some embodiments of the present application; Figure 5 A distribution diagram of the first theoretical area and the second theoretical area provided for some embodiments of the present application; Figure 6 A schematic diagram of a regional core provided for some embodiments of the present application; Figure 7 Schematic diagram of analysis curves fitted in some embodiments of the present application; Figure 8 A calibration device for quantum bit reading parameters provided in some embodiments of the present application; Fig. 9 A schematic diagram of the structure of an electronic device provided for some embodiments of the present application. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0014] It should be noted that, in the description of this application, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence.

[0015] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0016] In classical bit computing, the value of a bit is fixed, that is, it is either 1 or 0. Therefore, when reading the value of a classical bit, the result is also fixed. However, in quantum computing, the state of a quantum bit (qubit) can be |0> state, |1> state, or superposition state of |0> and |1>. The superposition state can be expressed as a|0>+b|1>, where a and b are complex numbers. represents the probability that the result of reading the superposition quantum bit is the |0> state, It represents the probability that after reading the quantum bit in superposition state, the reading result is the |1> state. and Satisfy the normalization condition, that is + =1. Due to the probabilistic nature of the quantum bit state, when reading the quantum bit state, a single reading result cannot accurately reflect the true state of the quantum bit. In view of this, in some technologies, quantum calculations are performed multiple times to obtain a large number of quantum bits in the same superposition state, and the states of these quantum bits are read separately. By performing statistical analysis on the read quantum bit states, the first probability of the quantum bit being in the |0> state and the second probability of being in the |1> state can be determined, and then the true state of the quantum bit can be understood based on the first probability and the second probability.

[0017] Combined with reference Figure 1 , is a schematic diagram of a quantum bit state reading system 100 in some technologies. The quantum bit state reading system 100 can be used to read the quantum bit state of a single quantum computation. For example, suppose 50 quantum computations are required. After the first quantum computation is completed, the quantum bit state of the first quantum computation can be read by the quantum bit state reading system 100; after the second quantum computation is completed, the quantum bit state of the second quantum computation can be read by the quantum bit state reading system 100. And so on.

[0018] like Figure 1As shown, the quantum bit state reading system 100 includes a microwave source 11, a first waveform generator 12, a second waveform generator 13, a first mixer 14, a quantum chip 15, a second mixer 16, an amplifier 17 and a data acquisition card 18. Among them, the first mixer 14 and the second mixer 16 respectively include an oscillator end, an in-phase end, an orthogonal end and a radio frequency end. The oscillator end can also be called a LO (Local Oscillator) end, the in-phase end can also be called an I (In-phase) end, the orthogonal end can also be called a Q (Quadrature) end, and the radio frequency end can also be called an RF (Radio Frequency) end. The quantum chip 15 includes a planar waveguide resonant cavity 151 coupled to the quantum bit. The quantum bit coupled to the planar waveguide resonant cavity 151 is the quantum bit generated in the quantum computing process and the state needs to be read. The first waveform generator 12 and the second waveform generator 13 can be an arbitrary waveform generator.

[0019] based on Figure 1 In the quantum bit state reading system 100, the process of reading the quantum bit state may include the following steps: 1) The microwave source 11 generates a first signal as a local oscillator signal, and inputs the first signal into the first mixer 14 through the oscillator end of the first mixer 14. The first waveform generator 12 and the second waveform generator 13 generate two second signals with a phase difference of 90 degrees, and input the second signals into the first mixer 14 through the in-phase end and the quadrature end of the first mixer 14.

[0020] 2) The first mixer 14 mixes the first signal and the second signal to obtain a quantum bit read signal, and outputs the quantum bit read signal to the quantum chip 15 through the radio frequency end.

[0021] In the above steps 1) to 2), the first signal may be a microwave signal having an intermediate frequency difference from the qubit read frequency, and the second signal may be an intermediate frequency signal. The qubit read frequency refers to the frequency of the qubit read signal output by the first mixer 14. The intermediate frequency generally refers to a frequency between 50 Hz and 300 Hz. By controlling the frequencies of the first signal and the second signal, the qubit read frequency may be controlled. The amplitude of the qubit read signal depends on the input strength of the first signal and the second signal, and the envelope of the qubit read signal depends on the envelope of the second signal.

[0022] 3) When the qubit read signal is transmitted in the planar waveguide resonant cavity 151 of the quantum chip 15, since the planar waveguide resonant cavity 151 is coupled with the qubit, the transmission characteristics of the planar waveguide resonant cavity 151 will be affected by the state of the qubit, and the output signal of the quantum chip 15 will change under different qubit states. Therefore, by analyzing the output signal of the quantum chip 15, the state of the qubit can be determined.

[0023] For ease of understanding, a curve is drawn with the quantum bit reading frequency output by the first mixer 14 as the horizontal axis and the signal amplitude output by the quantum chip 15 as the vertical axis, and it can be obtained that Figure 2 Schematic diagram of transmission characteristics of the planar waveguide resonant cavity 151 shown. Figure 2 In FIG. 1 , curve 21 represents the transmission characteristics of the planar waveguide resonant cavity 151 when the quantum bit state is |1> state; dashed line 22 represents the transmission characteristics of the planar waveguide resonant cavity 151 when the quantum bit state is |0> state. Figure 2 It can be seen that when the quantum bit reading frequency is to When the quantum bit read frequency is between , the state of the quantum bit is different, and the signal output by the quantum chip 15 is different. When the quantum bit state is |1>, the signal amplitude output by the quantum chip 15 is H1, and when the quantum bit state is |0>, the signal amplitude output by the quantum chip 15 is H2. In this way, when the quantum bit reading frequency is known, the quantum bit state can be determined by analyzing the signal amplitude output by the quantum chip 15. Specifically, the output signal of the quantum chip 15 can be analyzed based on the following steps 4) and 5).

[0024] 4) The output signal of the quantum chip 15 is input to the radio frequency end of the second mixer 16, and at the same time, the first signal generated by the microwave source 11 is input to the oscillator end of the second mixer 16. In this way, the target signal for determining the state of the quantum bit can be demodulated at the in-phase end or the orthogonal end of the second mixer 16.

[0025] 5) After the target signal is input into the amplifier 17 for amplification processing, the data acquisition card 18 can collect the signal output by the amplifier 17 according to the specified data acquisition duration. The signal output by the amplifier 17 can be called a read feedback signal, and the read feedback signal refers to a signal including quantum bit state information. The data acquisition duration refers to the single duration of the data acquisition card 18 collecting the read feedback signal. For example, when the data acquisition duration is 5 milliseconds, the duration of each time the data acquisition card 18 collects the read feedback signal is 5 milliseconds; when the data acquisition duration is 10 milliseconds, the duration of each time the data acquisition card 18 collects the read feedback signal is 10 milliseconds.

[0026] By performing Fourier transform on the collected read feedback signal, a frequency domain signal can be obtained. According to the frequency of the second signal, the signal characteristic value (such as signal amplitude and phase) at the corresponding frequency can be extracted from the frequency domain signal. By analyzing the extracted signal characteristic value, the quantum bit state can be determined. For example, assuming that the frequency of the second signal is f, the signal characteristic value at frequency f can be extracted from the frequency domain signal after Fourier transform. By analyzing the signal characteristic value at frequency f, the quantum bit state can be obtained.

[0027] In this application, the above-mentioned qubit reading frequency and data acquisition duration are collectively referred to as qubit reading parameters. The value of the qubit reading parameter will affect the reading fidelity of the qubit state. Reading fidelity refers to the accuracy of the read qubit state. For example, the following exemplifies several examples of how qubit reading parameters affect reading fidelity.

[0028] 1) By Figure 1 It can be seen that at different qubit reading frequencies, the signal discrimination of the quantum chip 15 in different qubit states is different. When the quantum chip 15 outputs a signal with different amplitudes based on different quantum bit states, the signal discrimination is relatively large; when the quantum bit reading frequency is and When the quantum chip 15 outputs a signal whose amplitude is different from that of the quantum bit state, the difference is small, that is, the signal discrimination is small. When the signal discrimination is large, the signal output by the quantum chip 15 in the quantum bit|0> state and the quantum bit|1> state can be accurately distinguished, thereby improving the reading fidelity of the quantum bit state; when the signal discrimination is small, the signal output by the quantum chip 15 in the quantum bit|0> state and the quantum bit|1> state cannot be accurately distinguished, thereby reducing the reading fidelity of the quantum bit state.

[0029] 2) Due to the energy relaxation effect in the quantum computing process, when the quantum bit state is in the |1> state, slow energy leakage will occur. In this case, if the data acquisition time is too long, the probability of the quantum bit changing from the |1> state to the |0> state will also increase, resulting in the quantum bit in the |1> state being incorrectly determined as the |0> state, reducing the reading fidelity of the quantum bit state.

[0030] 3) If the data acquisition time is too short, the frequency domain signal with high signal-to-noise ratio cannot be obtained during Fourier analysis, which will also reduce the reading fidelity of the quantum bit state.

[0031] It can be seen that the value of the qubit reading parameter is closely related to the reading fidelity of the qubit state. When determining the value of the qubit reading parameter, it is necessary to comprehensively consider the qubit reading frequency and data collection duration. At present, in some technologies, due to inaccurate setting of the qubit reading parameter, the read qubit state is not accurate enough, which in turn affects the accuracy of the quantum computing results.

[0032] In view of this, the present application provides a calibration method for quantum bit reading parameters, which can improve the accuracy of quantum bit reading parameters, thereby making the read quantum bit state more accurate and improving the accuracy of quantum computing results. The calibration method can be applied to electronic devices. Electronic devices include but are not limited to tablet computers, desktop computers, laptop computers, etc. Figure 3 , which is a flow chart of the calibration method provided in some embodiments of the present application. Figure 3 In the calibration method, the following steps are included: Step S301, obtaining multiple candidate quantum bit reading frequencies.

[0033] Specifically, the alternative qubit reading frequency refers to a plurality of pre-obtained qubit reading frequencies that will cause the quantum chip 15 to output different signals in different qubit states. Under different alternative qubit reading frequencies, the signal difference output by the quantum chip 15 in different qubit states may be different. For example, suppose that three alternative qubit reading frequencies F1, F2, and F3 are obtained. Under the alternative qubit reading frequency F1, the difference in the signal output by the quantum chip 15 in the qubit|0> state and the qubit|1> state may be large, and under the alternative qubit reading frequencies F2 and F3, the difference in the signal output by the quantum chip 15 in the qubit|0> state and the qubit|1> state may be small.

[0034] The multiple candidate quantum bit reading frequencies can be determined by the calibration personnel based on human experience and manually input into the electronic device that executes the calibration method. For example, the electronic device that executes the calibration method can display a frequency acquisition interface. Through the frequency acquisition interface, the electronic device can obtain the multiple quantum bit reading frequencies input by the staff as candidate quantum bit reading frequencies.

[0035] Alternatively, the multiple candidate quantum bit reading frequencies may also be automatically determined by an electronic device executing the calibration method based on the transmission characteristics of the quantum chip 15 and a preset frequency screening logic.

[0036] In the subsequent embodiments of the present application, a better method for obtaining the alternative quantum bit reading frequency is provided, which will not be described here.

[0037] Step S302, for any candidate quantum bit reading frequency, read the quantum bit state according to the candidate quantum bit reading frequency, and collect the reading feedback signal at the candidate quantum bit reading frequency according to multiple different data collection time lengths.

[0038] Specifically, similar to the candidate quantum bit reading frequency, the multiple different data collection durations can be manually input into the electronic device executing the calibration method by the calibration personnel according to actual needs, or can be automatically determined by the electronic device executing the calibration method according to a preset duration division logic. This application does not limit the method for obtaining the data collection duration.

[0039] For ease of understanding, the following is an example of step S302. Assume that the different data collection durations are T1, T2, and T3, and the candidate quantum bit reading frequencies F1, F2, and F3 are obtained in step S301. Then, based on Figure 1 The quantum bit state shown is read 100, and the following steps can be performed in sequence: 1) Set the qubit read frequency to the candidate qubit read frequency F1, and set the state of the qubit to the known |0> state or |1> state. According to the data collection time T1, collect and obtain the read feedback signal S11; according to the data collection time T2, collect and obtain the read feedback signal S12; according to the data collection time T3, collect and obtain the read feedback signal S13. Repeat step 1) multiple times to obtain multiple groups of read feedback signals S11, multiple groups of read feedback signals S12, and multiple groups of read feedback signals S13.

[0040] 2) Set the qubit read frequency to the candidate qubit read frequency F2, and set the state of the qubit to the known |0> state or |1> state. According to the data collection time T1, collect and obtain the read feedback signal S21; according to the data collection time T2, collect and obtain the read feedback signal S22; according to the data collection time T3, collect and obtain the read feedback signal S23. Repeat step 2) multiple times to obtain multiple groups of read feedback signals S21, multiple groups of read feedback signals S22, and multiple groups of read feedback signals S23.

[0041] 3) Set the qubit read frequency to the candidate qubit read frequency F3, and set the state of the qubit to the known |0> state or |1> state. According to the data collection time T1, collect and obtain the read feedback signal S31; according to the data collection time T2, collect and obtain the read feedback signal S32; according to the data collection time T3, collect and obtain the read feedback signal S33. Repeat step 3) multiple times to obtain multiple groups of read feedback signals S31, multiple groups of read feedback signals S32, and multiple groups of read feedback signals S33.

[0042] Step S303, for any candidate quantum bit reading frequency, based on the read feedback signal collected at the candidate quantum bit reading frequency, determine the read fidelity within each data collection time.

[0043] For example, based on the read feedback signal collected in step S302, the following steps may be performed in sequence: 1) For the candidate quantum bit reading frequency F1, based on the obtained multiple groups of reading feedback signals S11, determine the reading fidelity R11 within the data collection time T1; based on the obtained multiple groups of reading feedback signals S12, determine the reading fidelity R12 within the data collection time T2; based on the obtained multiple groups of reading feedback signals S13, determine the reading fidelity R13 within the data collection time T3; 2) For the candidate qubit read frequency F2, based on the obtained multiple groups of read feedback signals S21, determine the read fidelity R21 within the data collection time T1; based on the obtained multiple groups of read feedback signals S22, determine the read fidelity R22 within the data collection time T2; based on the obtained multiple groups of read feedback signals S23, determine the read fidelity R23 within the data collection time T3; 3) For the alternative quantum bit reading frequency F3, based on the multiple groups of read feedback signals S31 obtained, determine the reading fidelity R31 within the data collection time T1; based on the multiple groups of read feedback signals S32 obtained, determine the reading fidelity R32 within the data collection time T2; based on the multiple groups of read feedback signals S33 obtained, determine the reading fidelity R33 within the data collection time T3.

[0044] In this way, the reading fidelity within different data collection times at each alternative quantum bit reading frequency is obtained.

[0045] Specifically, taking the determination of the reading fidelity R11 within the data collection time T1 based on multiple groups of reading feedback signals S11 as an example, the following steps may be included: 1) Perform Fourier transform on each group of read feedback signals S11, and determine the multiple quantum bit states actually read based on the frequency domain signals obtained after Fourier transform. For example, assuming that the multiple groups of read feedback signals S11 include read feedback signals S11A, S11B, S11C, ... S11N, then Fourier transform the read feedback signal S11A to determine a quantum bit state status1; Fourier transform the read feedback signal S11B to determine a quantum bit state status2. And so on, N quantum bit states can be obtained. Due to the influence of the value of the quantum bit state reading parameter, the N quantum bit states may not be exactly the same, for example, the first and third quantum bit states are |0> states, and the second quantum characteristic state is |1> state.

[0046] 2) Since the quantum bit state has been set to a known state during the signal acquisition process in step S302, the set quantum bit state can be compared with the quantum bit state obtained by Fourier transform, and the reading fidelity R11 within the data acquisition time T1 can be determined based on the comparison result. For example, assuming that in step S302, when the quantum bit reading frequency is the candidate quantum bit reading frequency F1, the quantum bit state is set to the |0> state, and multiple groups of reading feedback signals S11 are collected. In step S303, there are 10 |0> states and 2 |1> states in the quantum bit states determined based on the multiple groups of reading feedback signals S11, which means that 10 quantum bit states are correct and 2 quantum bit states are wrong, and the reading fidelity can be 0.83 (i.e., 10 / 10+2).

[0047] By analogy, the reading fidelity within different data collection times at each alternative quantum bit reading frequency can be determined.

[0048] Step S304: Among the obtained reading fidelity, the candidate quantum bit reading frequency and data collection duration corresponding to the maximum reading fidelity are used as calibrated quantum bit reading parameters.

[0049] For example, based on the examples in step S302 and step S303, it is assumed that the following results are obtained: At the candidate qubit reading frequency F1, the reading fidelity within the data collection time T1 is 0.83, the reading fidelity within the data collection time T2 is 0.75, and the reading fidelity within the data collection time T3 is 0.81; At the candidate quantum bit reading frequency F2, the reading fidelity within the data collection time T1 is 0.69, the reading fidelity within the data collection time T2 is 0.72, and the reading fidelity within the data collection time T3 is 0.80; At the candidate quantum bit reading frequency F3, the reading fidelity within the data collection time T1 is 0.91, the reading fidelity within the data collection time T2 is 0.93, and the reading fidelity within the data collection time T3 is 0.95; Since the reading fidelity of 0.95 is the maximum reading fidelity, the candidate quantum bit reading frequency F3 and the data acquisition time T3 can be used as the calibrated quantum bit reading parameters. After the calibration of the quantum bit reading parameters is completed, the quantum bit state obtained based on the Fourier transform can be used as the read quantum bit state when the quantum bit state is unknown.

[0050] In summary, in the technical solutions of some embodiments of the present application, at each candidate quantum bit reading frequency, the reading feedback signal is collected according to different data collection durations, and based on the collected reading feedback signal, the reading fidelity within different data collection durations at each candidate quantum bit reading frequency is determined. In this way, the quantum bit reading frequency and data collection duration can be comprehensively considered based on the determined reading fidelity. When the candidate quantum bit reading frequency and data collection duration corresponding to the maximum reading fidelity are used as calibrated quantum bit reading parameters, the calibrated quantum bit reading parameters can be made relatively optimal parameters, achieving the purpose of improving the accuracy of the quantum bit reading parameters, and thus making the read quantum bit state more accurate.

[0051] In some embodiments, obtaining multiple candidate quantum bit reading frequencies in step S301 may specifically include: When the qubit state is a |0> state, a first correspondence between the amplitude of the feedback signal and the qubit read frequency is statistically read, and when the qubit state is a |1> state, a second correspondence between the amplitude of the feedback signal and the qubit read frequency is statistically read; In the first corresponding relationship and the second corresponding relationship, searching for a quantum bit reading frequency interval in which the quantum bit reading frequency is the same but the amplitude difference of the reading feedback signal exceeds the difference threshold; Frequencies in the quantum bit read frequency interval are used as candidate quantum bit read frequencies.

[0052] Combined with reference Figure 2 The first corresponding relationship can be represented by curve 22, and the second corresponding relationship can be represented by curve 21. Based on curve 22 and curve 21, it is possible to find a quantum bit reading frequency interval where the quantum bit reading frequency is the same but the amplitude difference of the reading feedback signal exceeds the difference threshold. For example Figure 2 In less than and greater than In the frequency range, when the qubit reading frequency is the same, the amplitudes of curve 22 and curve 21 can be the same or lower than the difference threshold, which means that when the qubit reading frequency is less than and greater than When the quantum chip 15 outputs signals in the quantum bit|0> state and the quantum bit|1> state, there is no distinction or the distinction is small. Therefore, the frequencies in these two frequency intervals cannot be used as the quantum bit reading frequencies. ~ In this frequency range, when the quantum bit reading frequency is the same, the amplitudes of curve 22 and curve 21 are quite different. Therefore, ~ This frequency range is used as the quantum bit reading frequency range.

[0053] After the quantum bit reading frequency interval is determined, multiple frequencies can be selected in the quantum bit reading frequency interval as candidate quantum bit reading frequencies.

[0054] In the above embodiment, by statistically calculating the first correspondence relationship and the second correspondence relationship between the amplitude of the read feedback signal and the quantum bit read frequency in different quantum bit states, and based on the first correspondence relationship and the second correspondence relationship, searching for the quantum bit read frequency interval in which the quantum bit read frequency is the same but the amplitude difference of the read feedback signal exceeds the difference threshold. In this way, it is possible to avoid introducing invalid candidate quantum bit read frequencies that cannot cause the quantum chip 15 to output different signals in different quantum bit states, thereby ensuring the calibration accuracy of the quantum bit read parameters.

[0055] In some embodiments, the first correspondence relationship and the second correspondence relationship may be counted based on the following method: When the quantum bit state is in any of the |0> state and the |1> state, changing the frequency of at least one of the first signal and the second signal, and statistically reading the amplitude change trend of the feedback signal and the frequency change trend of the quantum bit reading frequency; Based on the amplitude variation trend and the frequency variation trend, a first corresponding relationship or a second corresponding relationship is obtained.

[0056] Specifically, by changing the frequency of at least one of the first signal and the second signal, the quantum bit reading frequency can be changed accordingly, and then the statistical result can be obtained. Figure 2 The curve shown.

[0057] In this embodiment, considering that after Fourier transform, it is necessary to extract the signal characteristic value at the second signal frequency, if the second signal frequency is always in a changing state, it is not conducive to the subsequent signal characteristic value extraction. In view of this, the frequency of the second signal can be fixed to the target frequency and the frequency of the first signal can be changed. Specifically, the target frequency can be one of the frequencies within the above-mentioned intermediate frequency range. In this way, the complexity of the subsequent Fourier transform can be reduced, thereby reducing the complexity of parameter calibration.

[0058] In some embodiments, the above-mentioned using a frequency in the quantum bit reading frequency interval as a candidate quantum bit reading frequency may include: Starting from the minimum frequency of the quantum bit reading frequency range, the frequencies are filtered according to the preset frequency step, and the filtered frequencies are used as candidate quantum bit reading frequencies.

[0059] Specifically, in the quantum bit reading frequency range ~ , and the frequency step is In the case of , , ,……, . Among them, the frequency step When the frequency step is smaller, more candidate quantum bit reading frequencies can be screened. During the parameter calibration process, the parameter calibration accuracy can be improved by traversing more candidate quantum bit reading frequencies. In the case of large frequency, the amount of data processing can be reduced. The frequency step size can be selected according to the actual situation. For example, the frequency step It can be 0.2 Hz or 0.8 Hz.

[0060] In some embodiments, for any candidate qubit reading frequency in step S302, performing qubit state reading according to the candidate qubit reading frequency, and collecting a read feedback signal at the candidate qubit reading frequency according to a plurality of different data collection durations may include: When the quantum bit state is a |0> state, collecting a first read feedback signal at the candidate quantum bit read frequency according to a plurality of different data collection durations; When the quantum bit state is the |1> state, a second read feedback signal is collected at the candidate quantum bit reading frequency according to a plurality of different data collection durations.

[0061] For example, assume that in step S301, candidate quantum bit reading frequencies F1, F2, and F3 are obtained, and a plurality of different data collection durations are T1, T2, and T3. Figure 1 The quantum bit state shown is read 100, and the following steps can be performed in sequence: 1) After setting the state of the quantum bit to the |0> state, perform the following steps: The qubit reading frequency is set to the candidate qubit reading frequency F1, and the first reading feedback signal S111 is collected according to the data collection time T1; the first reading feedback signal S121 is collected according to the data collection time T2; and the first reading feedback signal S131 is collected according to the data collection time T3. Repeat step 1) multiple times to obtain multiple groups of first reading feedback signals S111, multiple groups of first reading feedback signals S121, and multiple groups of first reading feedback signals S131.

[0062] The qubit reading frequency is set to the candidate qubit reading frequency F2, and the first reading feedback signal S211 is collected according to the data collection time T1; the first reading feedback signal S221 is collected according to the data collection time T2; and the first reading feedback signal S231 is collected according to the data collection time T3. Repeat step 2) multiple times to obtain multiple groups of first reading feedback signals S211, multiple groups of first reading feedback signals S221, and multiple groups of first reading feedback signals S231.

[0063] The qubit read frequency is set to the candidate qubit read frequency F3, and the first read feedback signal S311 is collected according to the data collection time T1; the first read feedback signal S321 is collected according to the data collection time T2; and the first read feedback signal S331 is collected according to the data collection time T3. Repeat step 3) multiple times to obtain multiple groups of first read feedback signals S311, multiple groups of first read feedback signals S321, and multiple groups of first read feedback signals S331.

[0064] 2) After setting the state of the quantum bit to the |1> state, perform the following steps: The qubit reading frequency is set to the candidate qubit reading frequency F1, and the second reading feedback signal S112 is collected according to the data collection time T1; the second reading feedback signal S122 is collected according to the data collection time T2; and the second reading feedback signal S132 is collected according to the data collection time T3. Repeat step 1) multiple times to obtain multiple groups of second reading feedback signals S112, multiple groups of second reading feedback signals S122, and multiple groups of second reading feedback signals S132.

[0065] The qubit read frequency is set to the candidate qubit read frequency F2, and the second read feedback signal S212 is collected according to the data collection time T1; the second read feedback signal S222 is collected according to the data collection time T2; and the second read feedback signal S232 is collected according to the data collection time T3. Repeat step 2) multiple times to obtain multiple groups of second read feedback signals S212, multiple groups of second read feedback signals S222, and multiple groups of second read feedback signals S232.

[0066] The qubit read frequency is set to the candidate qubit read frequency F3, and the second read feedback signal S312 is collected according to the data collection time T1; the second read feedback signal S322 is collected according to the data collection time T2; and the second read feedback signal S332 is collected according to the data collection time T3. Repeat step 3) multiple times to obtain multiple groups of second read feedback signals S312, multiple groups of second read feedback signals S322, and multiple groups of second read feedback signals S332.

[0067] After obtaining the read feedback signals of the quantum bit |0> state and |1> state at different data collection durations at each candidate quantum bit read frequency, the first read feedback signal and the second read feedback signal collected at the same data collection duration at the same candidate quantum bit read frequency can be merged, and the read fidelity within the corresponding data collection duration can be determined based on the merged read feedback signal. For example, after merging the above-mentioned first read feedback signal S111 and the second read feedback signal S112, the read fidelity within the data collection duration T1 at the candidate quantum bit read frequency F1 is determined based on the merged read feedback signal. In this way, when determining the read fidelity within the data collection duration T1 at the candidate quantum bit read frequency F1, the read feedback signals of the quantum bit |0> state and |1> state can be simultaneously referred to, so that the determined read fidelity can be more objective and accurate.

[0068] In some embodiments, for any one of the first read feedback signal and the second read feedback signal, collecting the read feedback signal at the candidate qubit read frequency according to a plurality of different data collection durations may include: Collecting a read feedback signal at the candidate quantum bit read frequency according to a specified time period; Divide the specified duration into multiple different sub-collection durations; The read feedback signals collected in each sub-collection time length are used as read feedback signals collected according to a plurality of different data collection time lengths.

[0069] For example, take the collection of the above-mentioned first read feedback signals S111, S121, and S131 as an example. When the state of the quantum bit is the |0> state and the quantum bit read frequency is set to the candidate quantum bit read frequency F1, the read feedback signal at the candidate quantum bit read frequency F1 can be collected according to the specified time length T. After the read feedback signal within the specified time length T is collected, the specified time length T can be divided into a plurality of different sub-collection time lengths T1, T2, and T3, and then the read feedback signal collected within the sub-collection time length T1 can be used as the read feedback signal S111, the read feedback signal collected within the sub-collection time length T2 can be used as the read feedback signal S121, and the read feedback signal collected within the sub-collection time length T3 can be used as the read feedback signal S131.

[0070] By collecting and reading feedback signals in a manner of dividing a specified time length into a plurality of different sub-collection time lengths, the number of signal collection times can be reduced.

[0071] Specifically, when dividing the specified duration T into multiple different sub-collection durations, the first sub-collection duration with a duration change step can be divided from the specified duration according to the preset duration change step; and based on the sub-collection durations obtained by division, the duration change step is accumulated to obtain the next sub-collection duration. Specifically, the duration change step is defined as t, then the first sub-collection duration is 0~t, the second sub-collection duration is 0~2t, the third sub-collection duration is 0~3t, and so on, until the sub-collection duration 0~T is obtained.

[0072] For example, assuming T=9 seconds, t=3 seconds, the collection of the above-mentioned first read feedback signals S111, S121, and S131 is still taken as an example. When the state of the quantum bit is the |0> state and the quantum bit read frequency is set to the alternative quantum bit read frequency F1, the read feedback signal for 9 seconds can be collected first, and then the data collected within 0 to 3 seconds is used as the first read feedback signal S111, the data collected within 0 to 6 seconds is used as the first read feedback signal S121, and the data collected within 0 to 9 seconds is used as the third read feedback signal S131. In this way, multiple groups of read feedback signals of different lengths can be collected in a relatively short time, which is more efficient.

[0073] In some embodiments, collecting a read feedback signal at a candidate qubit read frequency according to a specified duration may include: Within multiple specified time periods, read feedback signals at the candidate quantum bit read frequencies are collected respectively to obtain multiple groups of read feedback signals, each group of read feedback signals includes read feedback signals collected according to multiple different data collection time periods.

[0074] For example, when the state of the quantum bit is the |0> state and the quantum bit reading frequency is the candidate quantum bit reading frequency F1, N groups of reading feedback signals can be collected within N specified time lengths. From each group of reading feedback signals, reading feedback signals collected according to multiple different data collection time lengths can be obtained; When the state of the quantum bit is the |0> state and the quantum bit reading frequency is the candidate quantum bit reading frequency F2, N groups of reading feedback signals can also be collected within N specified time lengths. From each group of reading feedback signals, reading feedback signals collected according to multiple different data collection time lengths can be divided; And so on. In this way, it can be ensured that there is enough data to analyze the reading fidelity, thereby improving the accuracy of the reading fidelity.

[0075] In some embodiments, for any candidate qubit reading frequency, determining the reading fidelity within each data collection time period based on the reading feedback signal collected at the candidate qubit reading frequency in step S303 may include: For any target data collection time, multiple groups of read feedback signals are screened to obtain multiple groups of read feedback signals collected according to the target data collection time; Perform Fourier transform on each group of read feedback signals collected according to the target data collection time, and extract the signal characteristic value at the target frequency from the transformed frequency domain signal; Based on the distribution of signal characteristic values ​​at the target frequency, the reading fidelity within the target data acquisition duration is determined.

[0076] In this embodiment, the target frequency is the frequency of the second signal.

[0077] For ease of understanding, the following is still explained by way of example. For example, assuming that when the state of the quantum bit is the |0> state and the quantum bit read frequency is the candidate quantum bit read frequency F1, N groups of read feedback signals AA are collected according to the specified time length T, and when the state of the quantum bit is the |1> state and the quantum bit read frequency is the candidate quantum bit read frequency F1, N groups of read feedback signals BB are collected according to the specified time length T. If it is necessary to determine the read fidelity within the target data collection time length T1 at the candidate quantum bit read frequency F1, the N groups of read feedback signals AA can be screened to obtain the N groups of read feedback signals collected according to the target data collection time length T1, and the N groups of read feedback signals BB can be screened to obtain the N groups of read feedback signals collected according to the target data collection time length T1. In this way, a total of 2N groups of read feedback signals can be screened. In the 2N groups of read feedback signals screened, Fourier transform is performed on each group of read feedback signals, and 2N signal characteristic values ​​at the target frequency can be extracted.

[0078] Furthermore, since the quantum bit state has been set to a known value when reading the feedback signal, the actual quantum bit state corresponding to each set of read feedback signals can be determined when the set of read feedback signals is collected. For example, the first set of read feedback signals is collected when the quantum bit is in the |1> state, and the second set of read feedback signals is collected when the quantum bit is in the |0> state. Due to the influence of the quantum bit reading parameters, the extracted signal characteristic values ​​may not correspond to the actual quantum bit state. For example, the first set of read feedback signals is collected when the quantum bit is in the |1> state, but the signal characteristic values ​​extracted from the first set of read feedback signals correspond to the quantum bit |0> state.

[0079] In this embodiment, on the one hand, a first annotation can be set for the read feedback signal collected when the quantum bit is in the |1> state, and a second annotation can be set for the read feedback signal collected when the quantum bit is in the |0> state. When extracting signal eigenvalues ​​based on Fourier transform, if the annotation of the read feedback signal is the first annotation, the extracted signal eigenvalue is represented by a gray circle, and if the annotation of the read feedback signal is the second annotation, the extracted signal eigenvalue is represented by a white circle. In this way, based on the color of the circle, the correct quantum bit state corresponding to these signal eigenvalues ​​can be determined.

[0080] On the other hand, the extracted signal eigenvalues ​​are plotted in the IQ plane (i.e., the in-phase component and the orthogonal component plane) as follows: Figure 4 As shown. Figure 4 It can be seen that there are gray circles in the distribution area of ​​white circles, and white circles in the distribution area of ​​gray circles. The reason for this is that the signal characteristic value extracted from the read feedback signal is inaccurate. That is, according to the color of the circle, it can be determined that the corresponding correct quantum bit state should be the |0> state, but the quantum bit state determined by the extracted signal characteristic value is the |1> state. This means that due to the influence of the quantum bit reading parameters, an error has occurred in the process of reading the quantum bit state. For example, for Figure 4 For circle A on the right, since it is gray, it means that the correct quantum bit state corresponding to the circle should be the |1> state. However, due to reasons such as the long data collection time, an energy relaxation effect occurs in the process of reading the quantum bit state, causing circle A to finally appear in the right area.

[0081] It can be seen that the signal characteristic values ​​actually extracted are not distributed completely according to the theoretical situation. In view of this, in this embodiment, the reading fidelity within the target data acquisition time can be determined based on the distribution of the signal characteristic values ​​at the target frequency. Specifically, if there are more gray circles in the distribution area of ​​the white circles, or if there are more white circles in the distribution area of ​​the gray circles, it means that the reading fidelity is low.

[0082] Determining the reading fidelity based on the distribution of signal characteristic values ​​is more intuitive and has higher accuracy.

[0083] In some embodiments, determining the reading fidelity within the target data acquisition duration based on the signal characteristic value distribution at the target frequency includes: The signal characteristic value distribution area at the target frequency is divided into a first theoretical area and a second theoretical area, the first theoretical area is the theoretical distribution area of ​​the signal characteristic value when the quantum bit state is |0> state, and the second theoretical area is the theoretical distribution area of ​​the signal characteristic value when the quantum bit state is |1> state; The reading fidelity is determined based on the first theoretical region, the second theoretical region, and the actual distribution region of the signal characteristic values ​​in different quantum bit states.

[0084] Specifically, based on the signal eigenvalue clustering method, the signal eigenvalue distribution area can be divided into a first theoretical area and a second theoretical area to obtain Figure 5 Schematic diagram shown. Figure 5 In , the area on the left side of the dotted line represents the second theoretical area, and the area on the right side of the dotted line represents the first theoretical area. Based on the first theoretical area and the second theoretical area obtained by division, it can be determined that when the quantum bit state is |0>, the signal characteristic value at the target frequency is located in the first data amount E01 of the second theoretical area, and when the quantum bit state is |1>, the signal characteristic value at the target frequency is located in the second data amount E10 of the first theoretical area, and then the read fidelity can be determined based on the first data amount E01 and the second data amount E10. Specifically, the first data amount E01 and the second data amount E10 can be substituted into the preset formula to obtain the read fidelity, wherein in the preset formula, the read fidelity is inversely proportional to the first data amount and the second data amount. The preset formula can be shown as expression (1): Fa = 1- (E 01 / N+E 10 / N) / 2(1) Where Fa is the reading fidelity.

[0085] In some embodiments, the first theoretical region has a first region core, and the second theoretical region has a second region core. The region where the signal characteristic value is located can be determined based on the distance between the actual location of the signal characteristic value and the first region core and the second region core.

[0086] For example, refer to Figure 6 , which is a schematic diagram of the regional core provided in some embodiments of the present application. Figure 6 In the figure, the black circle in the area on the left side of the dotted line can represent the second area core of the second theoretical area, and the black circle in the area on the right side of the dotted line can represent the first area core of the first theoretical area. For any signal characteristic value represented by the white circle and the gray circle, assume that the distance between the position of the signal characteristic value and the second area core is X1, and the distance between the position of the signal characteristic value and the first area core is X2. If X1 is greater than X2, the signal characteristic value is located in the first theoretical area; if X1 is less than X2, the signal characteristic value is located in the second theoretical area; if X1 is equal to X2, the signal characteristic value can be located in both the first theoretical area and the second theoretical area. The theoretical area where the signal characteristic value is located can be determined according to actual needs.

[0087] In the above embodiment, the area where the signal characteristic value is located is determined based on the distance between the signal characteristic value and the location thereof and the first area core and the second area core, and the obtained result can be relatively accurate.

[0088] In some embodiments, among the obtained reading fidelities, the maximum reading fidelity can be screened based on the following method: For any candidate quantum bit reading frequency, based on the reading fidelity within each data collection time determined when the candidate quantum bit reading frequency is selected, find the target reading fidelity with the largest value; Among the target read fidelity values ​​corresponding to the read frequencies of the candidate quantum bits, the target read fidelity value with the largest value is selected as the maximum read fidelity value.

[0089] For example, assuming that at the candidate quantum bit reading frequency F1, the reading fidelity within the data collection time T1 is 0.83, the reading fidelity within the data collection time T2 is 0.75, and the reading fidelity within the data collection time T3 is 0.81; At the candidate quantum bit reading frequency F2, the reading fidelity within the data collection time T1 is 0.69, the reading fidelity within the data collection time T2 is 0.72, and the reading fidelity within the data collection time T3 is 0.80; At the candidate quantum bit reading frequency F3, the reading fidelity within the data collection time T1 is 0.91, the reading fidelity within the data collection time T2 is 0.93, and the reading fidelity within the data collection time T3 is 0.95; Then, among the read fidelities 0.83, 0.75, and 0.91 corresponding to the candidate quantum bit read frequency F1, it can be determined that the target read fidelity corresponding to the candidate quantum bit read frequency F1 is 0.91; Among the read fidelities 0.69, 0.72, and 0.80 corresponding to the candidate quantum bit read frequency F2, it can be determined that the target read fidelity corresponding to the candidate quantum bit read frequency F2 is 0.80; Among the read fidelities 0.91, 0.93, and 0.95 corresponding to the candidate quantum bit read frequency F3, it can be determined that the target read fidelity corresponding to the candidate quantum bit read frequency F3 is 0.95; Among the target reading fidelity corresponding to the reading frequencies of the candidate quantum bits, the maximum target reading fidelity is 0.95, and 0.95 can be used as the maximum reading fidelity.

[0090] Specifically, for any candidate quantum bit reading frequency, based on the reading fidelity within each data collection time determined when the candidate quantum bit reading frequency is selected, the target reading fidelity with the largest value is found, including: With the data collection time as the horizontal axis and the reading fidelity as the vertical axis, a fitting analysis curve is generated according to the reading fidelity within each data collection time determined when the candidate quantum bit reading frequency is used; The reading fidelity corresponding to the highest point of the analysis curve is taken as the target reading fidelity.

[0091] Specifically, Figure 7 Schematic diagram of the analytical curve fitted in some embodiments of the present application. Figure 7 It can be seen that due to the energy relaxation effect and the influence of the data length used for analysis on the Fourier transform signal-to-noise ratio, the curve of the reading fidelity first increases and then decreases.

[0092] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method.

[0093] The embodiment of the present application also provides a calibration device for quantum bit reading parameters, in conjunction with reference to Figure 8 , a calibration device for quantum bit reading parameters provided in some embodiments of the present application. Figure 8 In the process, the calibration device for the quantum bit reading parameters includes: A data acquisition module 801 is used to acquire a plurality of candidate quantum bit reading frequencies; A signal acquisition module 802 is used to read the quantum bit state according to the candidate quantum bit reading frequency for any candidate quantum bit reading frequency, and to collect a read feedback signal at the candidate quantum bit reading frequency according to a plurality of different data acquisition durations; A fidelity determination module 803 is used to determine the read fidelity within each data collection time for any candidate qubit read frequency based on a read feedback signal collected at the candidate qubit read frequency; The data screening module 804 is used to use the candidate quantum bit reading frequency and data collection time corresponding to the maximum reading fidelity as calibrated quantum bit reading parameters in the obtained reading fidelity.

[0094] In some embodiments, the data acquisition module 801 is specifically used to: When the qubit state is a |0> state, a first correspondence between the amplitude of the feedback signal and the qubit read frequency is statistically read, and when the qubit state is a |1> state, a second correspondence between the amplitude of the feedback signal and the qubit read frequency is statistically read; In the first corresponding relationship and the second corresponding relationship, searching for a quantum bit reading frequency interval in which the quantum bit reading frequency is the same but the amplitude difference of the reading feedback signal exceeds the difference threshold; Frequencies in the quantum bit read frequency interval are used as candidate quantum bit read frequencies.

[0095] In some embodiments, the data acquisition module 801 is specifically used to: Starting from the minimum frequency of the quantum bit reading frequency range, the frequencies are filtered according to the preset frequency step, and the filtered frequencies are used as candidate quantum bit reading frequencies.

[0096] In some embodiments, the qubit reading frequency is the frequency of the qubit reading signal, and the qubit reading signal is obtained by mixing the first signal output by the microwave source and the second signal output by the waveform generator; the data acquisition module 801 is specifically used to count the first corresponding relationship and the second corresponding relationship based on the following method: When the quantum bit state is in any of the |0> state and the |1> state, changing the frequency of at least one of the first signal and the second signal, and statistically reading the amplitude change trend of the feedback signal and the frequency change trend of the quantum bit reading frequency; Based on the amplitude variation trend and the frequency variation trend, a first corresponding relationship or a second corresponding relationship is obtained.

[0097] In some embodiments, the data acquisition module 801 is specifically used to: The frequency of the second signal is fixed to the target frequency and the frequency of the first signal is changed.

[0098] In some embodiments, the signal acquisition module 802 is specifically used for: When the quantum bit state is a |0> state, collecting a first read feedback signal at the candidate quantum bit read frequency according to a plurality of different data collection durations; When the quantum bit state is the |1> state, a second read feedback signal is collected at the candidate quantum bit reading frequency according to a plurality of different data collection durations.

[0099] In some embodiments, for any one of the first read feedback signal and the second read feedback signal, the signal acquisition module 802 is specifically configured to: Collecting a read feedback signal at the candidate quantum bit read frequency according to a specified time period; Divide the specified duration into multiple different sub-collection durations; The read feedback signals collected in each sub-collection time length are used as read feedback signals collected according to a plurality of different data collection time lengths.

[0100] In some embodiments, the signal acquisition module 802 is specifically used for: According to the preset duration change step, a first sub-collection duration with a duration equal to the duration change step is divided from the specified duration; On the basis of the sub-collection durations that have been divided, the duration change step is accumulated to obtain the next sub-collection duration.

[0101] In some embodiments, the signal acquisition module 802 is specifically used for: Within multiple specified time periods, read feedback signals at the candidate quantum bit read frequencies are collected respectively to obtain multiple groups of read feedback signals, each group of read feedback signals includes read feedback signals collected according to multiple different data collection time periods.

[0102] In some embodiments, the fidelity determination module 803 is specifically used to: For any target data collection time, multiple groups of read feedback signals are screened to obtain multiple groups of read feedback signals collected according to the target data collection time; Fourier transform is performed on each group of read feedback signals collected according to the target data collection time, and the signal characteristic value at the target frequency is extracted from the transformed frequency domain signal; Based on the distribution of signal characteristic values ​​at the target frequency, the reading fidelity within the target data acquisition duration is determined.

[0103] In some embodiments, the fidelity determination module 803 is specifically used to: The signal characteristic value distribution area at the target frequency is divided into a first theoretical area and a second theoretical area, the first theoretical area is the theoretical distribution area of ​​the signal characteristic value when the quantum bit state is |0> state, and the second theoretical area is the theoretical distribution area of ​​the signal characteristic value when the quantum bit state is |1> state; The reading fidelity is determined based on the first theoretical region, the second theoretical region, and the actual distribution region of the signal characteristic values ​​in different quantum bit states.

[0104] In some embodiments, the fidelity determination module 803 is specifically used to: Determine that when the qubit state is |0>, the signal characteristic value at the target frequency is located in the first data amount of the second theoretical region, and when the qubit state is |1>, the signal characteristic value at the target frequency is located in the second data amount of the first theoretical region; Based on the first amount of data and the second amount of data, a read fidelity is determined.

[0105] In some embodiments, the fidelity determination module 803 is specifically used to: The region where the signal characteristic value at the target frequency is located is determined based on the following method: The area where the signal characteristic value is located is determined according to the distance between the actual location of the signal characteristic value and the first area core and the second area core.

[0106] In some embodiments, the fidelity determination module 803 is specifically used to: Substituting the first data amount and the second data amount into a preset formula, the reading fidelity is obtained, wherein in the preset formula, the reading fidelity is inversely proportional to the first data amount and the second data amount.

[0107] In some embodiments, among the obtained reading fidelities, the fidelity determination module 803 is specifically configured to select the maximum reading fidelity based on the following method: For any candidate quantum bit reading frequency, based on the reading fidelity within each data collection time determined when the candidate quantum bit reading frequency is selected, find the target reading fidelity with the largest value; Among the target read fidelity values ​​corresponding to the read frequencies of the candidate quantum bits, the target read fidelity value with the largest value is selected as the maximum read fidelity value.

[0108] In some embodiments, the fidelity determination module 803 is specifically used to: With the data collection time as the horizontal axis and the reading fidelity as the vertical axis, a fitting analysis curve is generated according to the reading fidelity within each data collection time determined when the candidate quantum bit reading frequency is used; The reading fidelity corresponding to the highest point of the analysis curve is taken as the target reading fidelity.

[0109] The description of the features in the embodiment corresponding to the calibration device can refer to the relevant description of the embodiment corresponding to the calibration method, which will not be repeated here.

[0110] Combined with reference Fig. 9 An embodiment of the present application further provides an electronic device, including a memory 10 and a processor 20, wherein the memory 10 stores a computer program, and the processor 20 is configured to run the computer program to execute the steps in any one of the above-mentioned calibration method embodiments.

[0111] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above-mentioned calibration method embodiments when running.

[0112] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0113] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps in any of the above-mentioned calibration method embodiments are implemented.

[0114] An embodiment of the present application also provides another computer program product, including a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in any of the above-mentioned calibration method embodiments are implemented.

[0115] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0116] The above is a detailed introduction to the calibration method, device, equipment and storage medium for quantum bit reading parameters provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A method for calibrating quantum bit reading parameters, characterized in that: The method comprises: Obtain multiple candidate quantum bit reading frequencies; For any of the candidate quantum bit reading frequencies, perform quantum bit state reading according to the candidate quantum bit reading frequency, and collect read feedback signals at the candidate quantum bit reading frequency according to a plurality of different data collection durations; For any of the candidate quantum bit reading frequencies, based on a read feedback signal collected at the candidate quantum bit reading frequency, determining the read fidelity within each of the data collection durations; In the obtained reading fidelity, the candidate quantum bit reading frequency and data acquisition duration corresponding to the maximum reading fidelity are used as calibrated quantum bit reading parameters.

2. The calibration method according to claim 1, characterized in that: The step of obtaining a plurality of candidate quantum bit reading frequencies comprises: When the qubit state is a |0> state, a first correspondence between the amplitude of the feedback signal and the qubit read frequency is statistically read, and when the qubit state is a |1> state, a second correspondence between the amplitude of the feedback signal and the qubit read frequency is statistically read; In the first corresponding relationship and the second corresponding relationship, searching for a quantum bit reading frequency interval in which the quantum bit reading frequency is the same but the amplitude difference of the reading feedback signal exceeds the difference threshold; The frequency in the quantum bit reading frequency interval is used as the candidate quantum bit reading frequency.

3. The calibration method according to claim 2, characterized in that: The using a frequency in the quantum bit reading frequency interval as the candidate quantum bit reading frequency comprises: Starting from the minimum frequency of the quantum bit reading frequency interval, the frequencies are screened according to a preset frequency step, and the screened frequencies are used as the candidate quantum bit reading frequencies.

4. The calibration method according to claim 2, characterized in that: The qubit reading frequency is the frequency of the qubit reading signal, and the qubit reading signal is obtained by mixing the first signal output by the microwave source and the second signal output by the waveform generator; The first corresponding relationship and the second corresponding relationship are counted based on the following method: When the quantum bit state is any one of the |0> state and the |1> state, changing the frequency of at least one of the first signal and the second signal, and counting the amplitude change trend of the read feedback signal and the frequency change trend of the quantum bit read frequency; Based on the amplitude change trend and the frequency change trend, the first corresponding relationship or the second corresponding relationship is obtained.

5. The calibration method according to claim 4, characterized in that: The changing the frequency of at least one of the first signal and the second signal comprises: The frequency of the second signal is fixed to a target frequency and the frequency of the first signal is changed.

6. The calibration method according to claim 1, characterized in that: The step of collecting a read feedback signal at the candidate quantum bit read frequency according to a plurality of different data collection durations includes: When the quantum bit state is a |0> state, collecting a first read feedback signal at the candidate quantum bit read frequency according to a plurality of different data collection durations; When the quantum bit state is the |1> state, a second read feedback signal is collected at the candidate quantum bit reading frequency according to a plurality of different data collection durations.

7. The calibration method according to claim 6, characterized in that: For any one of the first read feedback signal and the second read feedback signal, collecting the read feedback signal at the candidate quantum bit read frequency according to a plurality of different data collection durations includes: Collecting a read feedback signal at the candidate quantum bit read frequency according to a specified time length; Dividing the specified duration into a plurality of different sub-collection durations; The read feedback signals collected in each of the sub-collection time periods are used as read feedback signals collected according to a plurality of different data collection time periods.

8. The calibration method according to claim 7, characterized in that: The dividing the specified duration into a plurality of different sub-collection durations includes: According to a preset duration variation step, a first sub-collection duration having a duration equal to the duration variation step is divided from the specified duration; On the basis of the sub-collection durations obtained by division, the duration change step is accumulated to obtain the next sub-collection duration.

9. The calibration method according to claim 7, characterized in that: The step of collecting the read feedback signal at the candidate quantum bit read frequency according to the specified time period includes: Within the multiple specified time lengths, the read feedback signals at the candidate quantum bit read frequency are respectively collected to obtain multiple groups of read feedback signals, each group of read feedback signals respectively includes read feedback signals collected according to multiple different data collection time lengths.

10. The calibration method according to claim 9, characterized in that: The determining of the reading fidelity within each of the data collection durations based on the read feedback signal collected at the candidate quantum bit read frequency includes: For any target data collection time, screening out multiple groups of read feedback signals from the multiple groups of read feedback signals to obtain multiple groups of read feedback signals collected according to the target data collection time; Performing Fourier transformation on each group of read feedback signals obtained by screening according to the target data collection time, and extracting the signal characteristic value at the target frequency from the transformed frequency domain signal; Based on the signal characteristic value distribution at the target frequency, the reading fidelity within the target data acquisition time is determined.

11. The calibration method according to claim 10, characterized in that: The determining of the reading fidelity within the target data acquisition duration based on the signal characteristic value distribution at the target frequency includes: Dividing the signal characteristic value distribution area at the target frequency into a first theoretical area and a second theoretical area, wherein the first theoretical area is the theoretical distribution area of ​​the signal characteristic value when the quantum bit state is |0> state, and the second theoretical area is the theoretical distribution area of ​​the signal characteristic value when the quantum bit state is |1> state; The reading fidelity is determined based on the first theoretical region, the second theoretical region, and actual distribution regions of signal characteristic values ​​in different quantum bit states.

12. The calibration method according to claim 11, characterized in that: The determining of the reading fidelity based on the first theoretical region, the second theoretical region, and actual distribution regions of signal characteristic values ​​in different quantum bit states includes: Determine that when the qubit state is |0>, the signal characteristic value at the target frequency is located at a first data amount in the second theoretical region, and when the qubit state is |1>, the signal characteristic value at the target frequency is located at a second data amount in the first theoretical region; The read fidelity is determined based on the first data amount and the second data amount.

13. The calibration method according to claim 12, characterized in that: The first theoretical region has a first region core, and the second theoretical region has a second region core; The region where the signal characteristic value at the target frequency is located is determined based on the following method: The area where the signal characteristic value is located is determined according to the distance between the actual location of the signal characteristic value and the first area core and the second area core.

14. The calibration method according to claim 12, characterized in that: The determining the read fidelity based on the first data amount and the second data amount includes: Substituting the first data amount and the second data amount into a preset formula to obtain the reading fidelity, wherein in the preset formula, the reading fidelity is inversely proportional to the first data amount and the second data amount.

15. The calibration method according to claim 1, characterized in that: Among the obtained reading fidelities, the maximum reading fidelity is selected based on the following method: For any of the candidate quantum bit reading frequencies, based on the reading fidelity within each of the data collection time periods determined at the candidate quantum bit reading frequency, searching for a target reading fidelity with a maximum value; Among the target reading fidelities corresponding to the candidate quantum bit reading frequencies, the target reading fidelity with the largest value is selected as the maximum reading fidelity.

16. The calibration method according to claim 15, characterized in that: The step of searching for a target reading fidelity with a maximum value for any of the candidate quantum bit reading frequencies based on the reading fidelities within each of the data acquisition durations determined at the candidate quantum bit reading frequency comprises: With the data collection time as the horizontal axis and the reading fidelity as the vertical axis, a fitting analysis curve is formed according to the reading fidelity within each of the data collection time periods determined at the candidate quantum bit reading frequency; The reading fidelity corresponding to the highest point of the analysis curve is used as the target reading fidelity.

17. A calibration device for quantum bit reading parameters, characterized in that: The device comprises: A data acquisition module, used to obtain multiple candidate quantum bit reading frequencies; A signal acquisition module, for performing quantum bit state reading according to any of the candidate quantum bit reading frequencies, and collecting a read feedback signal at the candidate quantum bit reading frequency according to a plurality of different data acquisition durations; A fidelity determination module, for determining, for any of the candidate quantum bit reading frequencies, the reading fidelity within each of the data collection durations based on a read feedback signal collected at the candidate quantum bit reading frequency; The data screening module is used to use the candidate quantum bit reading frequency and data collection time corresponding to the maximum reading fidelity as the calibrated quantum bit reading parameters in the obtained reading fidelity.

18. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to execute the steps of implementing the calibration method as claimed in any one of claims 1 to 16.

19. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the calibration method according to any one of claims 1 to 16.

20. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the calibration method according to any one of claims 1 to 16 are implemented.

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