Compensation method and system for measuring IQ line imbalance, storage medium and electronic equipment

Abstract

The invention discloses a compensation method and system for measuring IQ circuit imbalance, a storage medium and electronic equipment, and the method comprises the steps: obtaining readout signals corresponding to different quantum states according to a resonant cavity of an IQ circuit, and carrying out the measurement of the quantum states through a first calculation model; the read-out signals pass through a power divider and a phase shifter to obtain frequency mixing signals of an I port and a Q port, the two frequency mixing signals are subjected to frequency mixing, low-pass filtering and ADC circuit processing, and sampling is carried out; performing normalization processing on the two mixing signals, and performing calculation through a second calculation model to obtain an unbalance factor; performing direct current bias compensation according to the imbalance factor, calculating a correction matrix, and performing imbalance compensation on the IQ line; according to the method, statistical processing is carried out on quantum state measurement data to obtain a calibration matrix, the basic principle is based on a linear equation solving theory and matrix inversion operation, statistical estimation is carried out on an IQ imbalance factor of a quantum state measurement circuit, compensation correction is carried out, the bit error rate is reduced, and quantum calculation performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum computers, and in particular to a compensation method, system, storage medium and electronic device for measuring IQ line imbalance. Background Art

[0002] At present, there are two methods for measuring quantum states: direct emission and direct sampling and IQ mixing. The equipment cost of direct emission and direct sampling will increase with the scale of quantum bits, while IQ mixing has a low cost and is more advantageous. The measurement principle of IQ mixing is related to the fact that the coupling of quantum bits in superconducting quantum computers will change the frequency of the resonant cavity. The direction of frequency movement depends on the state of the quantum bit. Therefore, by measuring the state of the resonant cavity, it can be known whether the quantum bit is in (or collapsed to) the ground state |0> or the excited state |1>.

[0003] However, in actual situations, in addition to down-converting useful signal components, IQ mixing will produce intrinsic leakage and sideband signals. If these mirror interferences are not eliminated, they will cause errors in the measurement results of the quantum state. The corresponding quantum state measurement results will be offset in the coordinate points on the actual IQ plane, causing IQ imbalance problems. When the offset is large, it will cause judgment errors and bit error rates, thus affecting the performance of the entire superconducting quantum computer. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings in the prior art and to propose a compensation method, system, storage medium and electronic device for measuring IQ line imbalance.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: a compensation method for measuring IQ line imbalance, comprising the steps of:

[0006] S1: obtaining readout signals corresponding to different quantum states according to the resonant cavity of the IQ circuit, and performing quantum state measurement according to the pulse intensity of the readout signal;

[0007] S2: obtaining mixed signals of the I port and the Q port through a power divider and a phase shifter for the readout signal, mixing, low-pass filtering, and ADC circuit processing the two mixed signals, and sampling;

[0008] S3: performing normalization processing on the two mixing signals, and calculating an imbalance factor through output signals of the I port and the Q port;

[0009] S4: Perform DC offset compensation according to the imbalance factor and calculate a correction matrix to compensate for IQ line imbalance.

[0010] As a further description of the above technical solution: in the step S1, the steps are included:

[0011] S11: applying a readout pulse to the resonant cavity, calculating the evolution path of the quantum bit by using the Langevin equation, and obtaining the readout signal;

[0012] S12: Perform quantum state measurement according to the readout signal and the pulse intensity of the readout signal to determine whether the quantum state is in a ground state or an excited state, and obtain the amplitude and phase.

[0013] As a further description of the above technical solution: in the step S2, the steps are included:

[0014] S21: determining a mixed local oscillator signal through a local oscillator port of the IQ line, and calculating the signals of the I port and the Q port to obtain the mixed signal;

[0015] S22: Mix the two mixed signals, perform low-pass filtering and digitize them using an ADC circuit, then perform sampling and statistical processing using a sampling resonator, and distinguish the obtained I-port and Q-port output signals.

[0016] As a further description of the above technical solution: the down-converted signal under ideal conditions and the actual down-converted signal after normalization are calculated respectively through the output signals of the I port and the Q port to obtain the imbalance factor and the bit error rate of the measurement result.

[0017] As a further description of the above technical solution: the imbalance factor includes an amplitude imbalance factor α and a phase imbalance factor between the I port and the Q port.

[0018] As a further description of the above technical solution: in the step S4, the steps are included:

[0019] S41: Calculate the average values ​​of the output signals of the I port and the Q port, estimate the DC offset, perform DC offset compensation, and calculate the correction matrix according to the amplitude imbalance factor, the sine value of the phase imbalance factor, and the cosine value of the phase imbalance factor;

[0020] S42: Perform an inverse operation according to the correction matrix, calculate by adding a correction amount, and generate a correction result.

[0021] As a further description of the above technical solution: average values ​​of the output signals of the I port and the Q port are calculated respectively, and the differences between the output signals of the I port and the Q port and the average values ​​are calculated respectively to eliminate the DC bias and perform compensation.

[0022] As a further description of the above technical solution: imbalance compensation is performed through a correction matrix, and then the correction matrix is ​​inversely operated, and according to the calculated imbalance factor, a correction amount is added to the actual normalized down-converted output signal to perform imbalance correction and generate a correction result.

[0023] It also includes a control system, which is applicable to the compensation method described in any one of the above technical solutions, including

[0024] The acquisition module obtains the readout signal corresponding to the quantum state according to the resonant cavity of the IQ circuit;

[0025] A signal processing module receives the readout signal sent by the acquisition module, obtains the mixed signal of the I port and the Q port after passing through the power divider and the phase shifter, and performs mixing, filtering and ADC circuit processing;

[0026] a calculation module, receiving the mixed signal sent by the signal processing module, performing normalization processing, and calculating an imbalance factor;

[0027] The compensation module performs direct current offset compensation according to the unbalance factor.

[0028] It also includes a computer-readable storage medium storing a computer program for the compensation method, wherein the computer program enables a computer to execute the compensation method as described in any one of the above technical solutions.

[0029] Also included is an electronic device, comprising:

[0030] one or more processors; memory; and

[0031] One or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the programs include a method for executing the compensation method described in any one of the above technical solutions.

[0032] The above technical solution has the following advantages or beneficial effects:

[0033] The calibration matrix is ​​obtained by statistically processing the quantum state measurement data. The basic principle is to statistically estimate the IQ imbalance factor of the quantum state measurement line based on the theory of linear equation solving and matrix inversion operations, so as to perform compensation correction to reduce the bit error rate and improve the performance of quantum computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The process of the compensation method proposed by the present invention Figure 1 ;

[0035] Figure 2 The process of the compensation method proposed by the present invention Figure 2;

[0036] Figure 3 The process of the compensation method proposed by the present invention Figure 3 ;

[0037] Figure 4 The process of the compensation method proposed by the present invention Figure 4 ;

[0038] Figure 5 It is a schematic diagram of the structure of the control system proposed by the present invention;

[0039] Figure 6 Schematic diagram of the evolution path of the cavity output results in IQ space under different quantum bit states;

[0040] Figure 7 A simulation diagram showing the effect of the imbalance factor on the quantum state measurement in the present invention;

[0041] Figure 8 It is a schematic diagram of the correction result in the present invention;

[0042] Fig. 9 This is a simulation diagram of the correction result in the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Reference Figure 1 , an embodiment of the present invention provides: a compensation method for measuring IQ line imbalance, comprising the steps of:

[0045] S1: Obtain readout signals corresponding to different quantum states according to the resonant cavity of the IQ circuit, and perform quantum state measurement according to the pulse intensity of the readout signal;

[0046] S2: The read signal is subjected to a power divider and a phase shifter to obtain mixed signals of the I port and the Q port, and the two mixed signals are mixed, low-pass filtered, processed by an ADC circuit, and sampled;

[0047] S3: normalize the two mixing signals and calculate the imbalance factor through the output signals of the I port and the Q port;

[0048] S4: Perform DC offset compensation according to the imbalance factor and calculate a correction matrix to compensate for the IQ line imbalance.

[0049] The applicant found in the study that the Hamiltonian of the coupling system between the quantum bit and the resonant cavity can be written as:

[0050]

[0051] in, is the reduced Planck constant, ω q is the quantum bit frequency, ω r is the resonant cavity frequency, is the resonant cavity frequency term, χ is the dispersion frequency shift, is the Pauli operator, represents the energy of N photons, where N can be any natural number. It can be seen that the coupling with the quantum bit will change the frequency of the resonant cavity, and the direction of the frequency movement depends on the state of the quantum bit. By measuring the state of the resonant cavity, it can be known whether the quantum bit is in (or collapses to) the ground state |0> or the excited state |1>.

[0052] During IQ measurement, a read pulse is required to be given to the resonant cavity. Under the influence of this pulse, the coherent states in the resonant cavity corresponding to different quantum bit states will have different evolution paths (refer to Figure 6 ), by solving the Langevin equation of the open system, we can get its specific evolution path operator:

[0053]

[0054] where ∈ is the intensity of the readout pulse, is the output field phase caused by the qubit, is the Pauli operator, is the dispersion frequency shift, t is the time, △ is the difference between the frequency of the resonant cavity and the frequency of the quantum bit, and g is the coupling strength.

[0055] The quantum state measurement I / Q circuit is also called IQ Mixer, which has four external interfaces, namely LO port (Localoscillator), RF port (Radio frequency), I port (In-phase) and Q port (quadrature). IF is the intermediate frequency output port, RF is the radio frequency input port, and LO local oscillator input port. The frequency input by the LO port during mixing modulation is ω LO The high-frequency reference signal will be evenly divided into two paths through the power divider and the phase of the path at the Q port will be increased by π / 2. The two signals will be respectively connected to the I and Q port input frequencies of ω IF , the phase difference of π / 2 is multiplied, and then combined again at the RF port, and finally the output frequency from the RF port is ω RO =ω LO +ωIF When mixing and demodulating, you only need to input the signal from the sample into the RF port and input the same signal as the signal modulation into the LO port to convert the high-frequency ω RO The signal is transformed into a relatively low frequency ω IF The signal is output from the I and Q ports. IF The signal can be directly collected by the data acquisition card, and then the amplitude, phase and other information can be obtained through Fourier transform.

[0056] In this embodiment, the IQ line imbalance calibration matrix is ​​obtained by statistically processing the quantum state measurement data. The basic principle is to statistically estimate the IQ imbalance factor of the quantum state measurement line based on the linear equation solving theory and the correction matrix inversion operation, so as to perform compensation correction to reduce the bit error rate and improve the performance of quantum computing.

[0057] Reference Figure 2 , in step S1, comprising the steps of:

[0058] S11: Apply a readout pulse to the resonant cavity, calculate the evolution path of the quantum bit through the Langevin equation, and obtain the readout signal;

[0059] S12: Perform quantum state measurement according to the pulse intensity of the readout signal to determine whether the quantum state is in a ground state or an excited state, and obtain the amplitude and phase.

[0060] The first calculation model is designed to calculate the quantum state according to the pulse intensity of the readout signal. The algorithm formula is as follows:

[0061]

[0062] Where ∈ is the intensity of the readout pulse, χ is the frequency shift of the cavity caused by dispersion coupling, κ is the coupling amount, and t is the time. is the phase of the output field caused by the qubit, and i is the imaginary unit.

[0063] In this embodiment, when the quantum bit is in the ground state |0>, the readout signal is:

[0064]

[0065] When the quantum bit is in the excited state |1>, the readout signal is:

[0066]

[0067] By comparing the two readout signals, it can be seen that the two signals are in the Q direction The evolution of is consistent, and in the direction of I port On the contrary, distinguishing different quantum states mainly depends on the readout signal in the direction of the I port.

[0068] Since the resonant cavity readout signal is a high-frequency signal, the frequency corresponds to the dispersion frequency shift χ, and the first calculation model is simplified:

[0069]

[0070] That is, the information of the IQ phase space is encoded into the amplitude A RO and phase θ RO The above is to facilitate subsequent processing, where Re is the real part.

[0071]

[0072] Get the amplitude and phase of the I-port and Q-port output signals.

[0073] Reference Figure 3 , in step S2, comprising the steps of:

[0074] S21: determining a mixed local oscillator signal through a local oscillator port of the IQ line, and calculating the signals of the I port and the Q port to obtain a mixed signal;

[0075] S22: The two mixed signals are mixed, low-pass filtered and digitized by an ADC circuit, and then sampled and statistically processed by a sampling resonator to distinguish the obtained I-port and Q-port output signals.

[0076] In this embodiment, the resonant cavity readout signal passes through a power divider and a phase shifter to obtain two mixed signals:

[0077]

[0078] The mixed local oscillator signal is the input requirement of the local oscillator port (LO), and the function form is: y(t) = A LO ·cos(ω LO t);

[0079] After the power divider and phase shifter, the two mixed signals are:

[0080]

[0081] Among them, A LO ,ω LO is the amplitude and frequency output from the LO port;

[0082] The output after mixing is:

[0083]

[0084]

[0085] After filtering through a low-pass filter, we get:

[0086]

[0087] Digital processing through ADC conversion circuit:

[0088]

[0089] Convert to plural form:

[0090]

[0091] Among them, f s is the signal sampling rate, is the sampling interval. In order to avoid the transient effect of the sampling resonator, a readout delay τ corresponding to the resonator line width is required. rd , τ rd ∝Q is about 200-500ns. IF [n1:n2] and Q[n1:n2] are statistically processed to obtain the statistics I and Q, where n1 and n2 are the signal sampling ranges. The calculation formula is as follows:

[0092]

[0093] Among them, M=n2-n1+1 is the number of sampling points.

[0094] According to the above calculation results and θ RO =tan -1 (Q / I). From the previous analysis, we know that in the IQ space, the resonant cavity output signal has different evolution paths when the quantum bit is in the ground state |0> and in the excited state |1>. The two can be distinguished on the IQ plane to achieve the purpose of quantum bit measurement.

[0095] The down-converted signal under ideal conditions and the actual down-converted signal after normalization are calculated respectively through the output signals of the I port and the Q port, and the unbalance factor and the bit error rate of the measurement result are obtained.

[0096] The second calculation model is designed to calculate the imbalance factor according to the output signals of the I port and the Q port. The algorithm formula is as follows:

[0097] I IF1 (t) = α·cos(ω IF t+θ RO )+β I ;

[0098]

[0099] Among them, I IF1 (t) is the output signal of the I port, Q IF1 (t) is the output signal of Q port, ω IF is the input frequency, θ RO is the phase, β I is the DC bias of the I port, β Q is the DC bias of the Q port, α represents the amplitude imbalance between the I port and the Q port, Indicates the phase imbalance between the I port and the Q port.

[0100] In this embodiment, the ideal down-converted signal is:

[0101]

[0102] Due to the problem of I / Q line imbalance, in addition to down-converting the useful signal components, mirror interference will also be generated. If these mirror interferences are not eliminated, they will cause errors in the measurement results of the quantum state, thereby affecting the performance of the entire superconducting quantum computer.

[0103] The actual normalized signal is calculated by the second calculation model to obtain the imbalance factor:

[0104] I IF1 (t) = α·cos(ω IF t+θ RO )+β I ;

[0105]

[0106] The imbalance factor includes the amplitude imbalance factor α and the phase imbalance factor between the I port and the Q port. α represents the amplitude imbalance between the I port and the Q port, Indicates the phase imbalance between the I port and the Q port, β I is the DC bias of the I port, β Q is the DC bias of the Q port.

[0107] The DC offset can be eliminated by estimating the mean of the I port and the Q port respectively. Therefore, it can be assumed that the DC offset has been eliminated. The signal after DC offset compensation is assumed to be:

[0108] I IF2 (t) = α·cos(ω IF t+θ RO )+α·I IF (t)

[0109]

[0110] After conversion:

[0111]

[0112] Due to the existence of the IQ line imbalance factor, the coordinate points of the corresponding quantum state measurement results on the actual IQ plane will be offset. When the offset is large, it will cause judgment errors and thus cause bit error rates.

[0113] After normalizing the amplitude factor, when the quantum bit is in the ground state |0>, the coordinates of the point on the IQ plane are measured as (cos(θ RO ), sin(θ RO )). The measurement coordinates where IQ imbalance exists are When the quantum bit is in the excited state |1>, the coordinates of the point on the IQ plane are measured as (cos(θ RO ), -sin(θ RO )). The measurement coordinates where IQ imbalance exists are

[0114] Reference Figure 7 According to the above analysis, simulation calculation is performed, assuming that the amplitude imbalance factor α is evenly distributed between 0.5 and 1.5, and the phase imbalance factor is a Gaussian distribution with zero mean and variance of 2 degrees. The phase of the output signal is θ RO =π / 64, the amplitude is normalized to 1, 2000 points are taken for simulation analysis, and the bit error rate is 9.1%.

[0115] Reference Figure 4 , in step S4, comprising the steps of:

[0116] S41: Calculate the average values ​​of the output signals of the I port and the Q port, estimate the DC offset, perform DC offset compensation, and calculate the correction matrix according to the amplitude imbalance factor, the sine value of the phase imbalance factor, and the cosine value of the phase imbalance factor;

[0117] S42: Perform an inverse operation based on the correction matrix, calculate by adding the correction amount, and generate a correction result.

[0118] The algorithm formula for estimating DC bias is as follows:

[0119] β I = IF1 (t)>;

[0120] β Q = IF1 (t)>; ​​

[0121] Among them, <> means finding the average value,

[0122] Eliminate DC bias and perform compensation. The algorithm is as follows:

[0123] I IF2 (t) = I IF1 (t)-β I ;

[0124] Q IF2 (t) = Q IF1 (t)-β Q ;

[0125] Among them, I IF2 (t) and Q IF2 (t) is the unbalanced signal at the I port and the Q port.

[0126] Imbalance compensation is performed through the correction matrix, and the algorithm formula is as follows:

[0127]

[0128] Perform inverse operation on the correction matrix, the algorithm formula is as follows:

[0129]

[0130] According to the calculated imbalance factor, a correction amount is added to the actual normalized down-converted output signal to perform imbalance correction and generate a correction result.

[0131] In this embodiment, the unbalanced signal is represented in the form of a correction matrix:

[0132]

[0133] Then perform the inverse operation on the correction matrix:

[0134]

[0135] Define the signal mean estimate as follows:

[0136]

[0137] Among them, T = 2π / ω represents the period of the single-point frequency signal. The above formula represents the DC component of the signal. For the signal I IF2 (t) After squaring and then taking the mean, we can get:

[0138]

[0139] The amplitude imbalance factor can be obtained:

[0140]

[0141] Similarly, we can get:

[0142]

[0143] The derived sine value of the phase imbalance factor is:

[0144]

[0145] The parameter names for adding corrections are shown in Table 1:

[0146]

[0147]

[0148] Table 1 The method for correction and compensation based on the above calculation results is as follows: Estimation of DC offset:

[0149] β I = IF1 (t)>β Q = IF1 (t)>

[0150] Eliminate DC bias:

[0151] I IF2 (t) = I IF1 (t)-β I

[0152] Q IF2 (t) = Q IF1 (t)-β Q

[0153] Estimate the amplitude imbalance factor:

[0154]

[0155] Estimate the sine of the phase mismatch factor:

[0156]

[0157] Estimate the cosine of the phase inconsistency factor:

[0158]

[0159] Calculate the correction matrix:

[0160]

[0161] Execute the I / Q imbalance compensation algorithm:

[0162] ​​

[0163] After completion, the calibration results are generated (refer to Figure 8 ), and generate a correction result diagram after simulation (refer to Fig. 9 ).

[0164] Example 2

[0165] Reference Figure 5 , a control system, characterized in that the control system is applicable to any compensation method in claims 1-8 above, including

[0166] Acquisition module 1, obtains a readout signal corresponding to the quantum state according to the resonant cavity of the IQ circuit;

[0167] Signal processing module 2 receives the readout signal sent by the acquisition module, obtains the mixed signal of the I port and the Q port after passing through the power divider and the phase shifter, and performs mixing, filtering and ADC circuit processing;

[0168] The calculation module 3 receives the mixed signal sent by the signal processing module, performs normalization processing, and calculates the imbalance factor;

[0169] The compensation module 4 performs DC offset compensation according to the unbalance factor.

[0170] It is understandable that the control system provided in the embodiment of the present invention corresponds to the above-mentioned compensation method, and the explanations, examples, beneficial effects and other parts of its relevant contents can refer to the corresponding contents in the compensation method, which will not be repeated here.

[0171] Example 3

[0172] A computer-readable storage medium stores a computer program for a compensation method, wherein the computer program causes a computer to execute the following steps:

[0173] S1: Obtain readout signals corresponding to different quantum states according to the resonant cavity of the IQ circuit, and perform quantum state measurement according to the pulse intensity of the readout signal;

[0174] S2: The read signal is subjected to a power divider and a phase shifter to obtain mixed signals of the I port and the Q port, and the two mixed signals are mixed, low-pass filtered, processed by an ADC circuit, and sampled;

[0175] S3: normalize the two mixing signals and calculate the imbalance factor through the output signals of the I port and the Q port;

[0176] S4: Perform DC offset compensation according to the imbalance factor and calculate a correction matrix to compensate for the IQ line imbalance.

[0177] Embodiment 4:

[0178] An electronic device, comprising:

[0179] one or more processors;

[0180] Memory; and

[0181] One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by one or more processors, the programs comprising steps for performing the following steps:

[0182] S1: Obtain readout signals corresponding to different quantum states according to the resonant cavity of the IQ circuit, and perform quantum state measurement according to the pulse intensity of the readout signal;

[0183] S2: The read signal is subjected to a power divider and a phase shifter to obtain mixed signals of the I port and the Q port, and the two mixed signals are mixed, low-pass filtered, processed by an ADC circuit, and sampled;

[0184] S3: normalize the two mixing signals and calculate the imbalance factor through the output signals of the I port and the Q port;

[0185] S4: Perform DC offset compensation according to the imbalance factor and calculate a correction matrix to compensate for the IQ line imbalance.

[0186] It should be noted that, through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment. In this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. Without more constraints, an element defined by the phrase "comprising a..." does not exclude the existence of other identical elements in the process, method, article or apparatus comprising the element.

[0187] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A compensation method for measuring IQ line imbalance, It is characterized in that Includes steps: S1: obtaining readout signals corresponding to different quantum states according to the resonant cavity of the IQ circuit, and performing quantum state measurement according to the pulse intensity of the readout signal; S2: obtaining mixed signals of the I port and the Q port through a power divider and a phase shifter for the readout signal, mixing, low-pass filtering, and ADC circuit processing the two mixed signals, and sampling; S3: performing normalization processing on the two mixing signals, and calculating an imbalance factor through output signals of the I port and the Q port; S4: Perform DC offset compensation according to the imbalance factor and calculate a correction matrix to compensate for IQ line imbalance.

2. The compensation method according to claim 1, Features: In the step S1, the steps are included: S11: applying a readout pulse to the resonant cavity, calculating the evolution path of the quantum bit by using the Langevin equation, and obtaining the readout signal; S12: Perform quantum state measurement according to the readout signal and the pulse intensity of the readout signal to determine whether the quantum state is in a ground state or an excited state, and obtain the amplitude and phase.

3. The compensation method according to claim 1, Features: In the step S2, the steps are included: S21: determining a mixed local oscillator signal through a local oscillator port of the IQ line, and calculating the signals of the I port and the Q port to obtain the mixed signal; S22: Mix the two mixed signals, perform low-pass filtering and digitize them using an ADC circuit, then perform sampling and statistical processing using a sampling resonator, and distinguish the obtained I-port and Q-port output signals.

4. The compensation method according to claim 1, Features: The down-converted signal under ideal conditions and the actual down-converted signal after normalization are calculated respectively through the output signals of the I port and the Q port, and the unbalance factor and the bit error rate of the measurement result are obtained.

5. The compensation method according to claim 4, Features: The imbalance factor includes an amplitude imbalance factor α and a phase imbalance factor between the I port and the Q port.

6. The compensation method according to claim 1, Features: In the step S4, the steps are included: S41: Calculate the average values ​​of the output signals of the I port and the Q port, estimate the DC offset, perform DC offset compensation, and calculate the correction matrix according to the amplitude imbalance factor, the sine value of the phase imbalance factor, and the cosine value of the phase imbalance factor; S42: Perform an inverse operation according to the correction matrix, calculate by adding a correction amount, and generate a correction result.

7. The compensation method according to claim 6, Features: The average values ​​of the output signals of the I port and the Q port are calculated respectively, and the differences between the output signals of the I port and the Q port and the average values ​​are calculated respectively to eliminate the DC bias and perform compensation.

8. The compensation method according to claim 6, Features: Imbalance compensation is performed through the correction matrix, and then the correction matrix is ​​inversely operated. According to the calculated imbalance factor, a correction amount is added to the actual normalized down-conversion output signal to perform imbalance correction and generate a correction result.

9. A control system, It is characterized in that The control system is applicable to the compensation method described in any one of claims 1 to 8, including: The acquisition module obtains the readout signal corresponding to the quantum state according to the resonant cavity of the IQ circuit; A signal processing module receives the readout signal sent by the acquisition module, obtains the mixed signal of the I port and the Q port after passing through the power divider and the phase shifter, and performs mixing, filtering and ADC circuit processing; A calculation module, receiving the mixed signal sent by the signal processing module, performing normalization processing, and calculating an imbalance factor; The compensation module performs direct current offset compensation according to the unbalance factor.

10. A computer-readable storage medium, It is characterized in that It stores a computer program for the compensation method, wherein the computer program enables a computer to execute the compensation method according to any one of claims 1 to 8.

11. An electronic device, It is characterized in that include: one or more processors; Memory; as well as One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for executing the compensation method according to any one of claims 1 to 8.

Images