Parameter calibration method of quantum bit reading system based on time domain response of resonant cavity

Abstract

The present invention discloses a parameter calibration method for a quantum bit reading system based on the time domain response of a resonant cavity, which relates to the field of quantum computing technology and comprises the following steps: state preparation; selecting a current reading frequency point and selecting one of two routes for processing, wherein one route is: preparing quantum bits respectively, obtaining reading cavity parameter information, bringing the reading cavity parameter information into a dynamic model, acquiring a transmission signal and storing it; the other route is: not taking any operation on the quantum bits, applying a reading pulse, obtaining a transmission signal and storing it; taking the next reading frequency point as the current reading frequency point and cyclically entering the above processing process until the total number of reading frequencies is reached, obtaining multiple groups of transmission signals after removing cavity signals, and obtaining parameters to be fitted in the dynamic model based on the transmission signals; the parameter calibration method can effectively test various parameters of the reading cavity at a specific reading frequency.

Description

Technical Field

[0001] The present invention relates to the field of quantum computing technology, and in particular to a parameter calibration method for a quantum bit reading system based on the time domain response of a resonant cavity. Background Art

[0002] The current scheme for superconducting quantum computing reading is generally a dispersion shift scheme coupled with a resonant cavity (called a reading cavity), plus an additional resonant cavity or resonant cavity system acting as a filter (called a Purcell filter) to suppress the Purcell effect.

[0003] The equations describing the superconducting quantum bit-reading cavity coupling (called dynamical equations) can be derived from the most basic quantum mechanical principles to a more complex form (called the general model). If the cavity kerr nonlinearity caused by the bit-cavity coupling is ignored, the cavity coherent state vector in the reading system can be simplified by the matrix equation composed of the following cavity quantum electrodynamics equations (called model A):

[0004] ;

[0005] in, is the vector of coherent states in each resonant cavity, is a vector of signal strengths input into each resonant cavity, is the imaginary number symbol, , are the difference between the driving frequency and the reading cavity frequency and the reading cavity dissipation rate, both of which are diagonal matrices. is the coupling strength between the cavities and is a symmetric matrix. When the bit is coupled to the reading system, the dispersion shift caused by the different states of the bit will change the corresponding resonant cavity. parameter, this change is not explicitly written in the above equation.

[0006] Due to the coupling between the resonant cavity and the outside (direct coupling or indirect coupling through other resonant cavity systems), the coherent state in the resonant cavity is leaking to the outside at a certain speed. The output signal of the resonant cavity can be obtained by superimposing the reflection of the signal incident into the resonant cavity. For the resonant cavity directly coupled with the outside, its output signal can be described by the input-output equation:

[0007] ;

[0008] in, is the electric field of the output signal, is the electric field of the input signal, subscript is the signal index, used to distinguish the direction or source of the signal. is the complex amplitude of the intracavity mode, indicating the intensity and phase of the intracavity signal, To read the cavity dissipation rate.

[0009] When the input and output signal reflections caused by impedance matching are not considered, the input signal The reading input signal (i.e. the signal input by the control device) is completely consistent and is not affected by the reading cavity output signal (which varies with the bit state). Therefore, the output signal can be directly subtracted to obtain the cavity internal signal. The difference (a multiplication factor and a negligible noise floor) is the difference. When considering the input and output signal reflections caused by impedance matching, the voltage reflection coefficient at each location must be further considered. At the reflection point, the input signal and the reflected signal follow the following equation (called the reflection equation):

[0010] ;

[0011] ;

[0012] in, is the signal incident on the cavity at the reflection point, is the signal emitted from the cavity to the reflection point, is the signal incident into the cavity from the other end of the reflection point, is the signal emitted from the reflection point to the outside of the cavity, is the reflection coefficient, which is a complex number representing the reflection amplitude and phase of the signal at the reflection point. Its modulus is usually in the range of Between. When When , it indicates complete reflection; when When , it indicates complete transmission. The transmission phase from the resonant cavity to the reflection point can be included in The phase is not shown here.

[0013] Based on the frequency response characteristics of microwave filter devices, the following methods are reported in the existing public literature to perform superconducting quantum bit reading system parameter calibration, which can be divided into three categories:

[0014] (a1) Using the AC-Stark effect caused by the coupling between the superconducting quantum bit and the reading cavity, including the change of the AC-Stark effect caused by the decay of the number of photons in the reading cavity after the removal of the reading microwave and fitting the corresponding equation (denoted as method 1A), scanning the reading microwave frequency to calibrate the curve described by the specific equation when the number of photons in the reading cavity is stable and fitting the corresponding equation (denoted as method 1B), etc.

[0015] (a2) Using the S parameter characteristics (S21, etc.) when the reading cavity is excited to a steady state and fitting the corresponding equations, etc.

[0016] (a3) Using the signal of decay after the reading cavity is excited to a steady state, test the signal decaying from the cavity and fit the corresponding equation, etc., where the decay signal usually refers to the signal released when a quantum bit or quantum system decays from an excited state to a ground state.

[0017] The above methods 1 to 3 have the following problems:

[0018] (b1) In the test using AC-Stark effect, method 1A is the most common, but due to the dependence on the bit X gate and the broadening of the cavity photon number itself, it is difficult to measure more accurate values ​​when the cavity relaxation rate is very fast; method 1B is a recently developed scheme, which can obtain three parameters: reading the cavity photon number, reading the cavity dispersion shift, and reading the cavity relaxation rate, but because it needs to scan and read the microwave pulse frequency, it is easy to be interfered by the adjacent reading cavity when the cavity frequency is closely arranged. In addition, 1A and 1B are also limited by the limitations of the AC-Stark effect itself, and it is difficult to test the parameters when the cavity photon number is very small. At the same time, because it is a multi-parameter spectrum scan, the test time is relatively long.

[0019] (b2) The solution using the steady-state S parameter characteristics also requires scanning and reading the microwave pulse frequency, which is easily affected by interference from the adjacent reading cavity. At the same time, this solution is limited by the impedance matching characteristics at each frequency point, requires the S parameters of the line to be flat, is greatly affected by the additional filters that may be installed, and has low accuracy.

[0020] (b3) The scheme for testing cavity decay signals. This scheme only uses the signals in the decay stage, has a small number of effective points, and the stability of the fitting results is not high enough.

[0021] (b4) In addition, none of the above test schemes can obtain the performance parameters of the Purcell filter system. Summary of the invention

[0022] Based on the technical problems existing in the background technology, the present invention proposes a parameter calibration method for a quantum bit reading system based on the time domain response of the resonant cavity, which can effectively test various parameters of the reading cavity at a specific reading frequency and solve the parameter calibration problem of the Purcell filter system.

[0023] The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity proposed in the present invention comprises the following steps:

[0024] Step 1: State preparation: calibrate the superconducting quantum bit reading system to be tested;

[0025] Step 2: Select the current reading frequency point and determine whether the current reading frequency point is within the range of a certain quantum bit reading cavity. If so, proceed to step 3; otherwise, proceed to step 4.

[0026] Step 3: Prepare the corresponding quantum bits to the 0 state and the 1 state respectively, apply the read pulse, collect the signal value C1 corresponding to the 0 state and the signal value C2 corresponding to the 1 state at each sampling point, use C1-C2 as the bit state information signal difference, and obtain the read cavity parameter information through the dynamic model fitting, bring the fitted read cavity parameter information into the dynamic model, obtain the transmission signal through cavity signal restoration and store it;

[0027] Step 4: No operation is performed on the quantum bit, a read pulse is applied, and the signal value C3 is acquired at each sampling point and stored as a transmission signal;

[0028] Step 5: Use the next reading frequency point as the current reading frequency point to loop into step 2 until the total number of reading frequencies is reached, and obtain multiple groups of transmission signals after removing the cavity signal. Process the multiple groups of transmission signals according to the dynamic model to obtain the parameters to be fitted in the dynamic model as calibration parameters.

[0029] Furthermore, in step three, the fitted reading cavity parameter information is brought into the dynamic model, and the transmission signal is obtained and stored through cavity signal restoration, specifically:

[0030] The fitted reading cavity parameter information is brought into the dynamic model, and the theoretical values ​​T1 and T2 of the output signal under different states of the quantum bit are calculated, and C1-T1 and C2-T2 are calculated to determine whether the difference between C1-T1 and C2-T2 is within the preset difference range;

[0031] If so, C1-T1 or C2-T2 is taken as the transmission signal after removing the cavity signal and stored;

[0032] If not, the fitted reading cavity parameter information is discarded and the sampling circuit or the dynamic model is checked for abnormality.

[0033] Furthermore, in step 1, the state preparation specifically includes: calibrating the X gate of the quantum bit coupled to the superconducting quantum bit reading system to be tested, and calibrating the read signal input / output timing alignment of the superconducting quantum bit reading system to be tested.

[0034] Furthermore, before step one, the correspondence between the quantum bit and the reading cavity and the response frequency range are checked based on the IQ distance, initial values ​​are set for various parameters of the filter, and a dynamic model of the superconducting quantum bit reading system to be tested is constructed using cavity quantum electrodynamics for subsequent parameter calibration.

[0035] Furthermore, in step three, based on the principle that the transmission signals are the same and only carry different quantum bit state information signals, C1-C2 is used as the bit state information signal difference.

[0036] Furthermore, in step 4, the signal value C3 is filtered, and the signal value C3 after the filtering is used as a transmission signal and stored.

[0037] Furthermore, based on steps one to three, the reading cavity parameters are directly obtained.

[0038] Furthermore, the superconducting quantum bit reading system corresponding to the parameter calibration method is a variety of superconducting quantum computing bit reading systems based on cavity quantum electrodynamics;

[0039] The various superconducting quantum computing bit reading systems include one or more stages of Purcell filters reading one or more reading cavities and intrinsic filter reading.

[0040] Furthermore, the dynamic model includes a dynamic equation, an input-output equation and a reflection equation.

[0041] A parameter calibration method for a quantum bit reading system based on the time domain response of a resonant cavity is used to realize parameter calibration of a quantum bit-free reading system, including:

[0042] S10, applying a reading pulse, collecting signal values ​​C3 at each sampling point and storing them as transmission signals;

[0043] S20, taking the next reading frequency point as the current reading frequency point and looping into S10 until the total number of reading frequencies is reached, obtaining multiple groups of transmission signals after removing the cavity signal, processing the multiple groups of transmission signals according to the kinetic model, obtaining the parameters to be fitted in the kinetic model as calibration parameters.

[0044] The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity provided by the present invention has the advantages that: the parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity provided in the structure of the present invention can effectively test various parameters of the reading cavity at a specific reading frequency, is less restricted by the reading cavity itself and the adjacent reading cavity conditions, and has a fast testing speed; by reasonably designing the quantum bit reading system to be tested, the present invention can solve the parameter calibration problem of the Purcell filter system and its external reflection conditions, and is helpful to improve the design of the superconducting quantum bit reading system and other multi-resonant cavity coupling systems. The present invention can also be used to test the number of photons filling in the reading cavity, which can be used for a variety of technologies, such as real-time cancellation of the Z waveform of the bit frequency during reading, parameterized data storage of weighted de-modulation, and finding the reading frequency at which the number of photons in the 01 state of the bit is the same during reading. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0046] Below, the technical solution of the present invention is described in detail through specific embodiments. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific implementation disclosed below.

[0047] The dynamic equation, input-output equation and reflection equation described in the background art together constitute the dynamic model used in this embodiment, from which the dynamic evolution process of each cavity can be obtained. The corresponding physical quantity can also be measured experimentally, for example, by preparing the bit to 0 and 1 states respectively and measuring the signal difference ( ) and fit the kinetic model to obtain the signal of the reading cavity , or directly measure the output signal of the entire system and fit the dynamic equation to obtain the information of each cavity; this is the basic principle of this embodiment.

[0048] Before calibrating the parameters of the quantum bit reading system, it is necessary to understand the basic state of the system, such as checking the correspondence between the quantum bit and the reading cavity and the response frequency range based on the IQ distance, setting initial values ​​for each parameter of the filter, and using cavity quantum electrodynamics to build a model of the superconducting quantum bit reading system to be tested (such as a dynamic model) for subsequent parameter calibration.

[0049] Regarding the dispersion shift scheme, the phase space division scheme is currently more commonly used. Under this scheme, a microwave pulse of a fixed frequency (called a read pulse) is emitted by the generating device, and is received by the reading device after passing through the reading system. The reading system will be different due to the different states of the bits, so the read pulse after passing through the reading system will carry the information of the bit state, so after the reading device samples and processes it, the division of the bit state can be given by the read pulse. The general processing scheme is to directly sum the sampled data points or to perform weighted summation according to a certain weight, and there is also a scheme for state division through machine learning. Common reading devices have the ability to collect and read pulse waveforms (amplitude and phase) at each time point, which is also one of the basic capabilities of the equipment required for this embodiment.

[0050] like Figure 1 As shown, the parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity proposed in the present invention includes the following steps:

[0051] Step 1: State preparation: calibrate the superconducting quantum bit reading system to be tested;

[0052] The state preparation is specifically as follows: calibrating the X gate of the quantum bit coupled to the superconducting quantum bit reading system to be tested, and calibrating the read signal input / output timing alignment of the superconducting quantum bit reading system to be tested.

[0053] Step 2: Select the current reading frequency point and determine whether the current reading frequency point is within the range of a certain quantum bit reading cavity. If so, proceed to step 3; otherwise, proceed to step 4.

[0054] Specifically, when the current reading frequency is within the range of a certain quantum bit reading cavity, proceed to step three; when the current reading frequency is not within the range of any quantum bit reading cavity, proceed to step four.

[0055] Step 3: Prepare the corresponding quantum bits to the 0 state and the 1 state respectively, apply the read pulse, collect the signal value C1 corresponding to the 0 state and the signal value C2 corresponding to the 1 state at each sampling point, and based on the principle that the transmission signals are the same and only the quantum bit state information signals are different, use C1-C2 as the bit state information signal difference, and obtain the read cavity parameter information through the dynamic model fitting, bring the fitted read cavity parameter information into the dynamic model, and obtain and store the transmission signal through cavity signal restoration;

[0056] Prepare the quantum bits at the current reading frequency point separately: that is, prepare the corresponding quantum bit to the 0 state, apply the reading pulse, collect and output the reading waveform at each sampling point to obtain the signal value C1; prepare the corresponding quantum bit to the 1 state, apply the reading pulse, collect and output the reading waveform at each sampling point to obtain the signal value C2. The process of fitting the dynamic model to obtain the reading cavity parameter information can be implemented using existing solutions, such as the curve_fit function under scipy.optimize, or the more primitive least_squares function, or some global search algorithms, to achieve the reading cavity parameter information through dynamic model fitting, where SciPy.optimize is a submodule in the SciPy scientific computing library, which is specifically used to solve various optimization problems; the curve_fit function can automatically fit the best parameter value according to the provided function model and data set, and return the fitted curve; the least_squares function is an optimization method in the Scipy library for solving nonlinear least squares problems. It finds the best fitting parameters by minimizing the residual sum of squares.

[0057] Among them, the fitted reading cavity parameter information is brought into the dynamic model and restored through the cavity signal, specifically: the fitted reading cavity parameter information is brought into the dynamic model, and the theoretical values ​​​​T1 and T2 of the output signal under different states (0 state and 1 state) of the quantum bit are calculated, C1-T1 and C2-T2 are calculated, and it is determined whether the difference between C1-T1 and C2-T2 is within the preset difference range; if so, C1-T1 or C2-T2 is used as the transmission signal after removing the cavity signal and stored, that is, the signal that does not carry the quantum bit state information; if not, the fitted reading cavity parameter information is discarded and the sampling circuit or the dynamic model is checked for abnormalities.

[0058] Among them, C1-T1 or C2-T2 is used as the transmission signal after removing the cavity signal. Since the difference between C1-T1 and C2-T2 is within the preset difference range, any one of C1-T1 or C2-T2 can be used as the transmission signal after removing the cavity signal to achieve the purpose of parameter calibration in this embodiment.

[0059] The two values ​​of T1 and T2 are obtained by substituting the fitted reading cavity parameters into the dynamic model. The calculation process is existing and can be briefly described as follows: Taking model A as an example, the fitting requires point-by-point reading waveform as input, which is substituted into the dynamic equation for point-by-point calculation to obtain the coherent state in the reading cavity; the experiment can only measure the coherent state difference in the cavity (obtained by C1-C2), and cannot clearly obtain the coherent state in the reading cavity. Therefore, the experimental difference and reading waveform measured by the experiment can only be used to fit the specific parameters of the reading cavity. After obtaining the parameters (fitted reading cavity parameter information), they can be substituted into the dynamic equation to calculate the coherent state in the reading cavity. This coherent state will leak into the reading output signal at a certain rate (that is, it affects the reading output, for details, please refer to the record of the dynamic model part). Therefore, the signal of the coherent state leakage in the cavity (i.e. C1-T1 and C2-T2) is subtracted from the reading output signal, and the remaining is the pure transmission signal that is not affected by the bit information.

[0060] Step 4: No operation is performed on the bit, a read pulse is applied, and the signal value C3 is acquired at each sampling point and stored as a transmission signal;

[0061] According to the model and signal conditions, the signal value C3 is filtered, and the signal value C3 after the filtering is used as a transmission signal and stored.

[0062] Step 5: Use the next reading frequency point as the current reading frequency point to loop into step 2 until the total number of reading frequencies is reached, and obtain multiple groups of transmission signals after removing the cavity signal. Process the multiple groups of transmission signals according to the dynamic model to obtain the parameters to be fitted in the dynamic model (i.e., filter information) as calibration parameters.

[0063] The read signal in steps 3, 4, and 5 can be a simple square wave or FLATTOP waveform (i.e., the convolution of a Gaussian waveform and a square wave), etc., or multiple square waves or MULTIFLATTOP waveforms (i.e., the convolution of a Gaussian waveform and multiple square waves with specific encoding) with specific encoding (length, amplitude, distance between square waves, etc. of each square wave). When using a square wave or FLATTOP waveform, etc., the dynamic model can ignore the reflection of input and output signals caused by impedance matching, and only use dynamic equations (such as general models or model A, etc.) and input-output equations to obtain system parameters without considering impedance matching. When using multiple square waves or MULITFLATTOP waveforms with specific encoding, etc., the reflection equation can be further considered on the basis of a square wave, etc., and the reflection points can be determined according to the actual physical system, and the voltage reflection coefficients of different reflection points, the distance from the incident / exit point of the reading system, and other information can be obtained through the overall response.

[0064] Through steps one to five, the existing technical route only uses the information of the reading system in steady state or part of the dynamic signal, and can only process the reading cavity but not the filter. This embodiment creatively uses the time domain signal to process the entire dynamic process, and can quickly obtain useful information based on the dynamic model. At the same time, the dynamic model architecture can be used to obtain information on the entire reading system, and information on the external coupling of the reading system, which greatly facilitates the acquisition of the real parameters of the reading system and the iteration of the reading design.

[0065] This embodiment can effectively test various parameters of the reading cavity at a specific reading frequency, is less restricted by the reading cavity itself and the conditions of adjacent reading cavities, and has a fast testing speed. By reasonably designing the quantum bit reading system to be tested, this embodiment can solve the parameter calibration problem of the Purcell filter system, and help improve the design of superconducting quantum bit reading systems and other multi-resonant cavity coupling systems.

[0066] In this embodiment, if only the reading cavity parameters are obtained, the corresponding steps S1 to S2 are:

[0067] S1. State preparation: calibrate the superconducting quantum bit reading system to be tested;

[0068] S2. Determine that the current reading frequency is within the range of a certain quantum bit reading cavity, prepare the corresponding quantum bits to the 0 state and the 1 state respectively, apply a reading pulse, and collect the signal value C1 corresponding to the 0 state and the signal value C2 corresponding to the 1 state at each sampling point. Based on the principle that the transmission signals are the same and only the signals carrying the quantum bit state information are different, C1-C2 is used as the bit state information signal difference, and the reading cavity parameter information is obtained through kinetic model fitting. The reading cavity parameter information is the required reading cavity parameter.

[0069] In this embodiment, if the system to be calibrated is a non-qubit reading system (such as a common test piece preparation scenario), the specific steps of the parameter calibration method are as follows S10 to S20:

[0070] S10, applying a reading pulse, collecting signal values ​​C3 at each sampling point and storing them as transmission signals;

[0071] S20, taking the next reading frequency point as the current reading frequency point and looping into S10 until the total number of reading frequencies is reached, obtaining multiple groups of transmission signals after removing the cavity signal, processing the multiple groups of transmission signals according to the kinetic model, obtaining the parameters to be fitted in the kinetic model as calibration parameters.

[0072] For the parameter calibration method of the quantum bit-free reading system, its dynamic model is slightly modified relative to the dynamic model of the quantum bit reading system. The dynamic model of the quantum bit reading system can simplify the dynamic model according to the response of the reading cavity. For example, when the dynamic equation uses model A, the response of the reading cavity can be obtained in step three, and the transmission signal can be modeled under model A by the specific order of the filter; but when calibrating the quantum bit-free reading system, since the dynamic model cannot be simplified, the filter and the reading cavity need to be fully modeled, the number of parameters increases, and the difficulty of the model to obtain the correct parameters will also increase. In this embodiment, if the measurement of the impedance matching outside the reading resonant cavity system is to be increased, the encoding of the reading pulse needs to be increased (for example, using a MULTIFLATTOP waveform, using a specific encoding to define the amplitude, duration and distance between each segment), and the input reading pulse in the model is modified accordingly and the reflection equation that conforms to the actual is added to the dynamic model. The reading waveform encoding can adopt any encoding method, and the ultimate goal is to improve the measurement sensitivity of the reflection point amplitude and the distance from the filter.

[0073] The core feature of the parameter calibration method described in this embodiment is to collect the reading pulse waveform (amplitude and phase) at each time point (sampling point), and compare it with the dynamic model describing the superconducting quantum bit reading system to be tested, so as to obtain the desired parameters in the dynamic model, thereby realizing the parameter calibration of the quantum bit reading system.

[0074] The superconducting quantum bit reading system corresponding to the parameter calibration method described in this embodiment can be a variety of superconducting quantum computing bit reading systems based on cavity quantum electrodynamics, including but not limited to the reading of one or more reading cavities by one / multiple stages of Purcell filters and the reading of intrinsic filters.

[0075] The dynamic model used in the parameter calibration method described in this embodiment is a complete dynamic model of the system to be calibrated, which can be a precise dynamic model or some approximate model of the precise model. The accuracy of the required parameters strictly depends on the model situation.

[0076] The data processing method used in the parameter calibration method described in this embodiment is to fit the evolution process of the corresponding kinetic model, and can be any computer algorithm that can achieve this purpose; the data preprocessing process is not limited, as long as the algorithm can restore the real data.

[0077] The measuring device used in the parameter calibration method described in this embodiment can be any device capable of collecting and reading pulse waveforms at each time point (sampling point), including but not limited to FPGA, ADC, oscilloscope (either down-converted or not, as long as the data can be restored), etc.

[0078] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A parameter calibration method for a quantum bit reading system based on the time domain response of a resonant cavity, characterized in that: The steps include: Step 1: State preparation: Use cavity quantum electrodynamics to construct a dynamic model of the superconducting quantum bit reading system to be tested, and calibrate the superconducting quantum bit reading system to be tested; Step 2: Select the current reading frequency point and determine whether the current reading frequency point is within the range of a certain quantum bit reading cavity. If so, proceed to step 3; otherwise, proceed to step 4. Step 3: Prepare the corresponding quantum bits to the 0 state and the 1 state respectively, apply the read pulse, collect the signal value C1 corresponding to the 0 state and the signal value C2 corresponding to the 1 state at each sampling point, use C1-C2 as the bit state information signal difference, and obtain the read cavity parameter information through the dynamic model fitting, bring the fitted read cavity parameter information into the dynamic model, calculate the theoretical values ​​T1 and T2 of the output signal under different states of the quantum bit, calculate C1-T1 and C2-T2, and judge whether the difference between C1-T1 and C2-T2 is within the preset difference range; if so, use C1-T1 or C2-T2 as the transmission signal after removing the cavity signal and store it; if not, discard the fitted read cavity parameter information and check whether the sampling circuit or the dynamic model is abnormal; Step 4: No operation is performed on the quantum bit, a read pulse is applied, and the signal value C3 is acquired at each sampling point and stored as a transmission signal; Step 5: Use the next reading frequency point as the current reading frequency point to loop into step 2 until the total number of reading frequencies is reached, and obtain multiple groups of transmission signals after removing the cavity signal. Process the multiple groups of transmission signals according to the dynamic model to obtain the parameters to be fitted in the dynamic model as calibration parameters.

2. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: In step 1, the state preparation specifically includes: calibrating the X gate of the quantum bit coupled to the superconducting quantum bit reading system to be tested, and calibrating the read signal input / output timing alignment of the superconducting quantum bit reading system to be tested.

3. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: Before step 1, the correspondence between the quantum bit and the reading cavity and the response frequency range are checked based on the IQ distance, and initial values ​​are set for various parameters of the filter for subsequent parameter calibration.

4. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: In step three, based on the principle that the transmission signals are the same and only carry different quantum bit state information signals, C1-C2 is used as the bit state information signal difference.

5. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: In step 4, the signal value C3 is filtered and the filtered signal value C3 is used as a transmission signal and stored.

6. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: Based on steps 1 to 3, the cavity parameters are directly obtained.

7. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: The superconducting quantum bit reading system corresponding to the parameter calibration method is a variety of superconducting quantum computing bit reading systems based on cavity quantum electrodynamics.

8. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: The dynamic model includes a dynamic equation, an input-output equation and a reflection equation.

9. The parameter calibration method of the quantum bit reading system based on the time domain response of the resonant cavity according to claim 1 is characterized in that: Parameter calibration for realizing quantum bit-free reading system, including: S10, applying a reading pulse, collecting signal values ​​C3 at each sampling point and storing them as transmission signals; S20, taking the next reading frequency point as the current reading frequency point and looping into S10 until the total number of reading frequencies is reached, obtaining multiple groups of transmission signals after removing the cavity signal, processing the multiple groups of transmission signals according to the kinetic model, obtaining the parameters to be fitted in the kinetic model as calibration parameters.

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