Method and apparatus for testing quantum chip, and quantum computer

Abstract

The application provides a quantum chip testing method and device and a quantum computer. The testing method comprises: obtaining data of at least two energy spectrum experiments performed by a to-be-tested quantum bit on the quantum chip; the data of each energy spectrum experiment comprises a plurality of frequency values of a quantum state control signal and a S 21 parameter amplitude, wherein the plurality of frequency values of the quantum state control signal are the same and the frequency of the read signal is different in the at least two energy spectrum experiments; obtaining the theoretical value of the S 21 parameter amplitude corresponding to the plurality of frequency values of the quantum state control signal in the at least two energy spectrum experiments; and obtaining the bit frequency of the to-be-tested quantum bit based on the data of the at least two energy spectrum experiments and all the theoretical values. The technical scheme of the application can accurately obtain the bit frequency of the to-be-tested quantum bit when there is no obvious peak in the energy spectrum experiment result and there is an interference peak.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of quantum computing, and particularly relates to a quantum chip testing method and device and a quantum computer. BACKGROUND

[0002] Quantum computing and quantum information is a cross-discipline based on the principles of quantum mechanics to achieve computing and information processing tasks, and has a very close relationship with quantum physics, computer science, information science, etc. In the past two decades, it has developed rapidly. Quantum algorithms based on quantum computers for factorization and unstructured search scenarios have shown much better performance than existing algorithms based on classical computers, and this direction has been expected to exceed the existing computing power. Since quantum computing has the potential to far exceed the performance of classical computers in solving certain problems, in order to realize a quantum computer, a quantum chip containing a sufficient number and sufficient quality of quantum bits is needed, and quantum logic gate operations and reading of quantum bits with very high fidelity are required.

[0003] A quantum chip is equivalent to a CPU for a traditional computer, and is the core component of a quantum computer. The quantum chip is a processor that performs quantum computing, and the quantum chip integrates multiple quantum bits and other devices. Before each quantum chip is formally put into use, the parameters of the quantum chip need to be tested and characterized, and the frequency parameter is an important component. The frequency parameter includes but is not limited to the transition frequency of the quantum bit, which is the frequency required to transition the quantum bit from the ground state to the first excited state.

[0004] The existing method for obtaining the bit frequency is a spectrum experiment, and the existing technology has also realized automatic testing of the bit frequency. However, the existing automatic testing method uses a peak search algorithm, and when the experimental results have other interference peaks and no obvious peaks, the obtained bit frequency is inaccurate or even unable to obtain the bit frequency.

[0005] Therefore, it is necessary to propose a new quantum chip testing method, device and quantum computer.

[0006] It should be noted that the information disclosed in the background section of the present application is only intended to deepen the understanding of the general background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art. SUMMARY

[0007] The purpose of the present application is to provide a quantum chip testing method, device and quantum computer to solve the problem of inaccurate bit frequency obtained in the prior art, or even the inability to obtain the bit frequency.

[0008] To solve the above technical problems, in a first aspect, the application provides a quantum chip testing method, comprising:

[0009] obtaining data of at least two energy spectrum experiments performed by a to-be-tested quantum bit on the quantum chip, wherein the data of each energy spectrum experiment comprises a plurality of frequency values of a quantum state control signal and a S 21 parameter amplitude corresponding to each frequency value of the quantum state control signal in the readout cavity;

[0010] obtaining theoretical values of the S 21 parameter amplitude corresponding to each frequency value of the quantum state control signal in the readout cavity in the at least two energy spectrum experiments;

[0011] obtaining a bit frequency of the to-be-tested quantum bit based on the data of the at least two energy spectrum experiments and all the theoretical values.

[0012] Preferably, the at least two energy spectrum experiments are two energy spectrum experiments.

[0013] Preferably, obtaining the frequency of the to-be-tested quantum bit based on the data of the two energy spectrum experiments and all the theoretical values comprises:

[0014] obtaining a difference between the S 21 parameter amplitudes corresponding to each frequency value of the quantum state control signal in the two energy spectrum experiments as a first difference;

[0015] obtaining a difference between the theoretical values of the S 21 parameter amplitudes corresponding to each frequency value of the quantum state control signal in the two energy spectrum experiments as a second difference;

[0016] obtaining the bit frequency of the to-be-tested quantum bit based on the first difference and the second difference.

[0017] Preferably, obtaining the bit frequency of the to-be-tested quantum bit based on the first difference and the second difference comprises:

[0018] obtaining a difference between the first difference and the second difference as a third difference;

[0019] determining whether the third difference exceeds a set value, and if not,

[0020] obtaining the bit frequency of the to-be-tested quantum bit based on the frequency value of the quantum state control signal corresponding to the third difference which does not exceed the set value.

[0021] Preferably, the set value is 3.

[0022] Preferably, the frequency value of the quantum state regulation signal corresponding to the third difference value not exceeding the set value is used to obtain the bit frequency of the to-be-tested quantum bit, comprising:

[0023] There are multiple third difference values not exceeding the set value, and the frequency value of the quantum state regulation signal corresponding to the third difference value not exceeding the set value is obtained, so that the frequency value of the quantum state regulation signal with the highest excited state occupation of the to-be-tested quantum bit is the bit frequency of the to-be-tested quantum bit.

[0024] Preferably, the frequency value of the quantum state regulation signal corresponding to the third difference value not exceeding the set value is used to obtain the bit frequency of the to-be-tested quantum bit, comprising:

[0025] There are multiple third difference values not exceeding the set value, and the frequency value of the quantum state regulation signal corresponding to the third difference value not exceeding the set value is obtained, so that the frequency value of the quantum state regulation signal with the highest excited state occupation of the to-be-tested quantum bit is the first frequency value;

[0026] The data of the to-be-tested quantum bit performing the energy spectrum experiment again includes multiple frequency values of the quantum state regulation signal and S 21 The parameter amplitude, wherein the multiple frequency values of the quantum state regulation signal are contained in an interval containing the first frequency value, and the frequency interval of the multiple frequency values of the quantum state regulation signal is less than the two energy spectrum experiments;

[0027] In the data of the energy spectrum experiment performed again, the S 21 The parameter amplitude, wherein the multiple frequency values of the quantum state regulation signal are contained in an interval containing the first frequency value, and the frequency interval of the multiple frequency values of the quantum state regulation signal is less than the two energy spectrum experiments;

[0028] Preferably, the interval is [first frequency value-20MHz, first frequency value+20MHz].

[0029] Preferably, the multiple frequency values of the quantum state regulation signal in the at least two energy spectrum experiments correspond to the S 21 The parameter amplitude, wherein the multiple frequency values of the quantum state regulation signal are contained in an interval containing the first frequency value, and the frequency interval of the multiple frequency values of the quantum state regulation signal is less than the two energy spectrum experiments;

[0030] Based on the amplitude of the to-be-tested quantum bit in the ground state, the amplitude in the excited state, and the probability of the quantum state regulation signal at each frequency value making the to-be-tested quantum bit in the ground state and the excited state in each energy spectrum experiment, the theoretical value of the S 21 The parameter amplitude.

[0031] Preferably, in each energy spectrum experiment, the quantum state control signal with each frequency value makes the to-be-tested quantum bit in the ground state and the excited state, and the probability of the to-be-tested quantum bit in the ground state and the excited state is obtained. The S 21 The theoretical value of the parameter amplitude includes:

[0032] According to the formula:

[0033] A=P e A e +P g A g

[0034] In each energy spectrum experiment, the S 21 The theoretical value of the parameter amplitude, wherein A is the theoretical value, Ae and Ag are the amplitudes of the to-be-tested quantum bit in the excited state and the ground state in each energy spectrum experiment, and Pe and Pg are the probabilities of the quantum state control signal with each frequency value making the to-be-tested quantum bit in the excited state and the ground state.

[0035] In a second aspect, the present application provides a testing device for a quantum chip, comprising:

[0036] An experimental data acquisition module configured to acquire data of at least two energy spectrum experiments performed by a to-be-tested quantum bit on the quantum chip, wherein the data of a single energy spectrum experiment includes a plurality of frequency values of a quantum state control signal and a S 21 The parameter amplitude, wherein the plurality of frequency values of the quantum state control signal are the same, but the frequencies of the read signal are different, in the at least two energy spectrum experiments;

[0037] A theoretical value acquisition module configured to acquire the S 21 The theoretical value of the parameter amplitude;

[0038] A bit frequency acquisition module configured to acquire the bit frequency of the to-be-tested quantum bit based on the data of the at least two energy spectrum experiments and all the theoretical values.

[0039] In a third aspect, the present application provides a readable storage medium having a computer program stored thereon, wherein the computer program is executed to implement the testing method provided by the first aspect of the present application.

[0040] In a fourth aspect, the present application provides a quantum computer comprising the testing device provided by the second aspect of the present application.

[0041] Compared with the prior art, the technical scheme of the application has the following beneficial effects:

[0042] The test method of the quantum chip provided by the application improves the accuracy of the obtained bit frequency. 21 The parameter amplitude is obtained, and the corresponding theoretical value is obtained, and the bit frequency of the to-be-tested quantum bit is obtained by comparing the theoretical value with the data obtained through the experiment, thereby improving the accuracy of the obtained bit frequency.

[0043] The test device of the quantum chip, the readable storage medium and the quantum computer provided by the application belong to the same inventive concept as the test method of the quantum chip provided by the application, and therefore have the same beneficial effects, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0045] Figure 1 The flowchart of the test method of the quantum chip provided by the embodiment of the application is shown in the figure.

[0046] Figure 2 The experimental result diagram of the energy spectrum experiment provided by the embodiment of the application is shown in the figure.

[0047] Figure 3 The structure diagram of the test device of the quantum chip provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0048] The specific embodiments of the application will be described in more detail below with reference to the accompanying drawings. The advantages and features of the application will be more apparent from the following description and claims. It should be noted that the drawings are very simplified and use non-precise proportions, only to facilitate, clear and assist in describing the purpose of the embodiments of the application.

[0049] In the description of the application, it should be understood that the terms "center", "upper", "lower", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the application.

[0050] In addition, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0051] In the embodiments of the present application, the quantum chip is a processor for performing quantum computation, a plurality of quantum bits and reading cavities corresponding to each other and coupled to each other are integrated on the quantum chip, each reading cavity is connected to a reading signal transmission line integrally arranged on the quantum chip at one end away from the corresponding quantum bit, each quantum bit is coupled to an XY signal transmission line (also called a quantum state control signal transmission line) and a Z signal transmission line (also called a bit frequency control signal transmission line), the XY signal transmission line is used for receiving a quantum state control signal, the Z signal transmission line is used for receiving a magnetic flux control signal, the magnetic flux control signal includes a bias voltage signal and / or a pulse bias control signal, the bias voltage signal and the pulse bias control signal can both control the bit frequency of the quantum bit, and the reading signal transmission line is used for receiving a reading signal and emitting a reading feedback signal.

[0052] The control and processing process of the quantum bit is briefly described as follows:

[0053] The frequency of the quantum bit is adjusted to the working frequency by the magnetic flux control signal on the Z signal transmission line, at this time, the quantum state control signal is applied through the XY signal transmission line to control the quantum state of the quantum bit in the initial state, and the quantum state of the controlled quantum bit is read by the reading cavity. Specifically, a frequency pulse signal, usually referred to as a "reading detection signal" (hereinafter referred to as a "reading signal"), is applied through the reading signal transmission line, the reading signal is usually a microwave signal with a frequency of 4-8 GHz, and the quantum state of the quantum bit is determined by analyzing the reading feedback signal output by the reading signal transmission line. The reason why the reading cavity can read the quantum state of the quantum bit is that different quantum states of the quantum bit produce different dispersion frequency shifts of the reading cavity, so that different quantum states of the quantum bit have different responses to the reading signal applied to the reading cavity, and the response signal is called a reading feedback signal. The reading cavity has obvious differences in response to the reading signal due to different quantum states of the quantum bit, i.e., the reading feedback signal has maximum distinguishability. Based on this, the quantum state of the quantum bit is determined by analyzing the reading feedback signal with a certain pulse length, for example, each reading feedback signal is converted into a coordinate point of an orthogonal plane coordinate system (i.e., an IQ plane coordinate system), and according to the position of the coordinate point and the reading criterion, it is determined whether the corresponding quantum state is |0> state or |1> state. It can be understood that |0> state and |1> state are two eigenstates of the quantum bit.

[0054] The embodiment of the present application provides a quantum chip testing method, referring to Figure 1 , Figure 1 The flowchart of the quantum chip testing method provided by the present application can be seen from Figure 1 , and the testing method comprises the following steps:

[0055] Step S1: obtaining data of at least two energy spectrum experiments performed by a to-be-tested quantum bit on the quantum chip, wherein the data of each energy spectrum experiment comprises a plurality of frequency values of a quantum state control signal and S 21 parameter amplitudes of a reading cavity corresponding to the plurality of frequency values of the quantum state control signal, wherein the plurality of frequency values of the quantum state control signal are the same in the at least two energy spectrum experiments, and the frequency of the reading signal is different;

[0056] Wherein, the to-be-tested quantum bit is any quantum bit on the quantum chip, and the execution process of the energy spectrum experiment is described as follows: the quantum state control signal transmission line coupled to the to-be-tested quantum bit is used to apply the quantum state control signal with different frequency values to the to-be-tested quantum bit, and the to-be-tested quantum bit is read by the reading signal to obtain the S 21 parameters of the reading cavity, when the frequency value of the quantum state control signal is the same as the frequency of the to-be-tested quantum bit, the to-be-tested quantum bit is excited to the |1> state, and the S 21 parameter amplitude of the reading cavity changes.

[0057] Generally, the experimental results of the energy spectrum experiment are as shown in Figure 2 , Figure 2 The experimental results of the energy spectrum experiment, wherein the abscissa is the frequency value of the quantum state control signal, and the ordinate is the S 21 parameter of the reading cavity. As can be seen from the figure, the S 21 parameter amplitude of the reading cavity is obviously higher at the frequency value position of the quantum state control signal than at other frequency value positions, that is, when the frequency value of the quantum state control signal is at this position, the S 21 parameter of the reading cavity changes obviously, that is, the frequency value of the quantum state control signal corresponding to this position is the bit frequency of the to-be-tested quantum bit. However, in the actual execution process of the energy spectrum experiment, due to the influence of noise, the experimental results of the energy spectrum experiment usually have multiple peak values, and the true bit frequency cannot be determined. The embodiment of the present application performs the energy spectrum experiment, and only needs to obtain the data of the energy spectrum experiment, specifically including the S 21 parameter amplitude of the reading cavity and the frequency value of the quantum state control signal corresponding to the S

[0058] In addition, in the step S1, the S 21The parameter is a forward transmission coefficient of the readout cavity. In different energy spectrum experiments, the quantum state control signals with the same frequency value set the to-be-measured quantum bit to the excited state with the same probability.

[0059] Step S2: acquiring S of the readout cavity corresponding to a plurality of frequency values of the quantum state control signal in the at least two energy spectrum experiments. 21 The theoretical value of the parameter amplitude;

[0060] In this way, the S of the readout cavity corresponding to each frequency value position in each energy spectrum experiment needs to be acquired. 21 The theoretical value of the parameter amplitude, if two energy spectrum experiments are performed, and the quantum state control signal has N different frequency values in each energy spectrum experiment, the number of all the theoretical values acquired is 2N.

[0061] Step S3: acquiring the bit frequency of the to-be-measured quantum bit based on the data of the at least two energy spectrum experiments and all the theoretical values.

[0062] In this way, if the number of energy spectrum experiments performed is greater than two, for example, the number of energy spectrum experiments performed is three, the experimental data of two energy spectrum experiments can be selected from the three energy spectrum experiments, and the theoretical values corresponding to the selected experimental data of the two energy spectrum experiments are compared to acquire the bit frequency.

[0063] In summary, the test method of the quantum chip provided in the embodiment of the present application acquires the data of at least two energy spectrum experiments, and acquires the corresponding S 21 The theoretical value of the parameter amplitude, and the bit frequency of the to-be-measured quantum bit is acquired based on the acquired experimental data and the theoretical value. The technical solution provided in the embodiment of the present application does not directly use the peak searching algorithm, but judges according to the experimental data and the theoretical value, so that the bit frequency of the to-be-measured quantum bit can be accurately acquired when there is no obvious peak in the experimental results of the energy spectrum experiment or there is an interference peak.

[0064] Further, in the test method of the quantum chip provided in the embodiment of the present application, the at least two energy spectrum experiments are two energy spectrum experiments.

[0065] By performing two energy spectrum experiments and acquiring the S 21 The theoretical value of the parameter amplitude, so that the execution efficiency of the test method of the quantum chip provided in the embodiment of the present application can be improved, and time can be saved.

[0066] Further, in the test method of the quantum chip provided in the embodiment of the present application, in the step S3, the bit frequency of the to-be-measured quantum bit is acquired based on the data of the two energy spectrum experiments and all the theoretical values, and the method comprises the following steps.

[0067] obtaining S from the two energy spectrum experiments corresponding to each frequency value of the quantum state control signal 21 The difference between the parameter amplitudes is a first difference.

[0068] obtaining S from the two energy spectrum experiments corresponding to each frequency value of the quantum state control signal 21 The difference between the theoretical values of the parameter amplitudes is a second difference.

[0069] Based on the first difference and the second difference, the bit frequency of the quantum bit to be measured is obtained.

[0070] The first difference is obtained from experimental data of two energy spectrum experiments. If the quantum state control signal has N different frequency values in each energy spectrum experiment, each frequency value corresponds to two S 21 The parameter amplitudes correspond to each other, and the two S 21 The difference between the parameter amplitudes is the first difference corresponding to the frequency value, that is, the number of the first difference is N, and the second difference is obtained from the S 21 The theoretical values of the parameter amplitudes are obtained. In each energy spectrum experiment, the number of theoretical values is the same as the number of frequency values, that is, each frequency value corresponds to two theoretical values, and the difference between the two theoretical values is the second difference corresponding to the frequency value. The number of the second difference is also N. Based on the first difference and the second difference, the bit frequency of the quantum bit to be measured can be obtained. By comparing the first difference and the second difference, if the first difference and the second difference differ greatly, since the second difference is the difference between theoretical values, it indicates that the data obtained by experiment in the two energy spectrum experiments is not accurate, and one of the experimental data is disturbed by noise. Therefore, the influence of the interference peak can be excluded, and the accurate bit frequency can be obtained.

[0071] Specifically, based on the first difference and the second difference, the bit frequency of the quantum bit to be measured is obtained, including:

[0072] The difference between the first difference and the second difference corresponding to each frequency value of the quantum state control signal is a third difference.

[0073] If the third difference does not exceed a set value, the bit frequency of the quantum bit to be measured is obtained based on the frequency value of the quantum state control signal corresponding to the third difference that does not exceed the set value.

[0074] The bit frequency of the quantum bit to be measured is obtained based on the frequency value of the quantum state control signal corresponding to the third difference that does not exceed the set value.

[0075] Specifically, the set value is 3, and in other embodiments of the application, other numerical values can also be used as the set value, and some experiments can be performed to set the value according to experience.

[0076] The corresponding frequency value can be determined by subtracting the first difference value from the second difference value, and if the third difference value is too large, it indicates that the experimental data is affected by noise, and the corresponding frequency position is an interference peak caused by noise.

[0077] Further, the test method of the quantum chip provided by the embodiment of the application, in the step S3, the frequency value of the quantum state control signal corresponding to the third difference value not exceeding the set value is used to obtain the bit frequency of the to-be-tested quantum bit, comprising:

[0078] There are multiple third difference values not exceeding the set value, and the frequency value of the quantum state control signal corresponding to the third difference value not exceeding the set value is obtained, so that the highest frequency value of the quantum state control signal occupied by the excited state of the to-be-tested quantum bit is taken as the bit frequency of the to-be-tested quantum bit.

[0079] Among them, there are usually multiple third difference values not exceeding the set value, and the frequency value corresponding to the third difference value not exceeding the set value needs to be obtained, so that the highest frequency value of the to-be-tested quantum bit excited state is taken as the bit frequency of the to-be-tested quantum bit, and the highest frequency value of the to-be-tested quantum bit excited state can be the frequency value corresponding to the point with the highest parameter amplitude in the S 21 spectrum experiment.

[0080] Further, the test method of the quantum chip provided by the embodiment of the application, in the step S3, the frequency value of the quantum state control signal corresponding to the third difference value not exceeding the set value is used to obtain the bit frequency of the to-be-tested quantum bit, comprising:

[0081] There are multiple third difference values not exceeding the set value, and the frequency value of the quantum state control signal corresponding to the third difference value not exceeding the set value is obtained, so that the highest frequency value of the quantum state control signal occupied by the excited state of the to-be-tested quantum bit is taken as the bit frequency of the to-be-tested quantum bit.

[0082] The data of the to-be-tested quantum bit performing the spectrum experiment again includes multiple frequency values of the quantum state control signal and the S 21 parameter amplitude of the reading cavity corresponding to each frequency value, wherein the multiple frequency values of the quantum state control signal are contained in an interval containing the first frequency value, and the frequency interval of the multiple frequency values of the quantum state control signal is smaller than the two spectrum experiments.

[0083] In the data obtained by performing the spectroscopy experiment again, the S 21 The frequency value of the frequency state control signal corresponding to the peak point of the parameter amplitude is the bit frequency of the quantum bit to be measured.

[0084] The frequency value is selected from the frequency values that do not exceed the set value according to the comparison between the third difference value and the set value. The frequency value that can make the excited state of the quantum bit to be measured highest is selected as the first frequency value. The spectroscopy experiment is performed again in the vicinity of the first frequency value range. The frequency value interval of the quantum state control signal in the spectroscopy experiment performed again is smaller, and the interval between each frequency value is also smaller. Finally, the frequency value corresponding to the peak point is obtained as the bit frequency according to the result of the spectroscopy experiment. The accuracy of the obtained bit frequency can be improved by performing the spectroscopy experiment again.

[0085] Specifically, in the embodiment of the present application, the interval is [first frequency value-20MHz, first frequency value+20MHz]. It should be noted that the interval can also be other frequency intervals containing the first frequency value, which is not limited here, as long as the interval of the frequency value of the quantum state control signal is smaller than the spectroscopy experiment in step S1.

[0086] Specifically, in step S2, the S 21 The theoretical value of the parameter amplitude includes:

[0087] Based on the amplitude of the quantum bit to be measured in the ground state, the amplitude in the excited state, and the probability of the quantum state control signal at each frequency value making the quantum bit to be measured in the ground state and the excited state in each spectroscopy experiment, the S 21 The theoretical value of the parameter amplitude.

[0088] Further, based on the amplitude of the quantum bit to be measured in the ground state, the amplitude in the excited state, and the probability of the quantum state control signal at each frequency value making the quantum bit to be measured in the ground state and the excited state in each spectroscopy experiment, the S 21 The theoretical value of the parameter amplitude includes:

[0089] According to the formula:

[0090] A=P e A e +P g A g

[0091] obtaining the S of the readout cavity corresponding to each frequency value of the quantum state control signal in each energy spectrum experiment 21 a theoretical value of a parameter amplitude, wherein A is the theoretical value, Ae and Ag are amplitudes of the to-be-tested quantum bit in an excited state and in a ground state respectively in each energy spectrum experiment, and Pe and Pg are probabilities of the to-be-tested quantum bit in the excited state and in the ground state respectively under the quantum state control signal of each frequency value.

[0092] It should be noted that the change of the frequency value of the readout signal does not change the probability of the to-be-tested quantum bit being set to the excited state by the corresponding quantum state control signal, and thus the Pe and Pg corresponding to the quantum state control signal of the same frequency value are the same in the two energy spectrum experiments, and the S 21 a theoretical value of a parameter amplitude, which depends on the respective Ag and Ag.

[0093] The Ag and Ae are explained here. As mentioned before, each time the readout feedback signal collected in the readout process is converted into a coordinate point in a quadrature plane coordinate system (i.e. an IQ plane coordinate system), and the corresponding quantum state is determined to be |0> or |1> according to the position of the coordinate point and the readout criterion. After a certain number of readouts, the points on the plane coordinate system will present two circular spots representing |0> and |1> respectively, and the amplitude of the circular spot center of the to-be-tested quantum bit in the ground state relative to the origin of the coordinate system is the amplitude Ag of the to-be-tested quantum bit in the ground state, and the amplitude of the circular spot center of the to-be-tested quantum bit in the excited state relative to the origin of the coordinate system is the amplitude Ae of the to-be-tested quantum bit in the excited state.

[0094] Based on the same inventive concept, the embodiment of the present application also provides a quantum chip testing device, which is described in detail in Figure 3 , Figure 3 The quantum chip testing device provided by the embodiment of the present application is described in detail from Figure 3 It can be seen that the quantum chip testing device comprises:

[0095] an experimental data acquisition module configured to acquire data of at least two energy spectrum experiments performed by a to-be-tested quantum bit on the quantum chip, the data of a single energy spectrum experiment comprising a plurality of frequency values of a quantum state control signal and S 21 a parameter amplitude, the plurality of frequency values of the quantum state control signal being the same in the at least two energy spectrum experiments, but the frequency of the readout signal being different;

[0096] a theoretical value acquisition module configured to acquire the S of the readout cavity corresponding to the plurality of frequency values of the quantum state control signal in the at least two energy spectrum experiments 21a theoretical value of a parameter amplitude;

[0097] a bit frequency acquisition module configured to acquire the bit frequency of the to-be-tested quantum bit based on data of the at least two times of spectrum experiments and all the theoretical values.

[0098] Based on the same inventive concept, the present application further provides a readable storage medium, which stores a computer program, and the computer program is executed to implement the test method provided by the embodiments of the present application.

[0099] Based on the same inventive concept, the present application further provides a quantum computer, which comprises the test device of the quantum chip provided by the embodiments of the present application.

[0100] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", or "a specific example" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments in a suitable manner. In addition, those skilled in the art can combine and integrate different embodiments or examples described in the present application.

[0101] The above are only preferred embodiments of the present application, and do not limit the present application in any way. Any person skilled in the art can make any form of equivalent replacement or modification, etc. to the technical solutions and technical contents disclosed in the present application without departing from the scope of the technical solutions of the present application, which still belongs to the protection scope of the present application.

Claims

1. A method of testing a quantum chip, characterized by, The method comprises: Obtaining data of at least two energy spectrum experiments performed by a to-be-measured quantum bit on the quantum chip, the data of each energy spectrum experiment including a plurality of frequency values of a quantum state regulation signal and a corresponding S 21 amplitude of the parameter, wherein in the at least two energy spectrum experiments, the plurality of frequency values of the quantum state regulation signal are the same, the frequency of the read signal is different, and the S 21 The difference between the amplitudes of the parameters is a first difference value. The S of the reading cavity corresponding to the plurality of frequency values of the quantum state regulation signal in the at least two energy spectrum experiments 21 The difference between the theoretical values of the parameter amplitudes is a second difference value 21 The difference between the theoretical values of the parameter amplitudes is a second difference value The third difference value is obtained by subtracting the second difference value from the first difference value corresponding to each frequency value of the quantum state control signal, and the bit frequency of the to-be-tested quantum bit is obtained based on the frequency value of the quantum state control signal corresponding to the third difference value not exceeding a set value.

2. The test method of claim 1, wherein, The at least two energy spectrum experiments are two energy spectrum experiments.

3. The test method of claim 1, wherein, The set value is 3.

4. The test method of claim 1, wherein, The bit frequency of the to-be-tested quantum bit is obtained based on the frequency value of the quantum state control signal corresponding to the third difference value not exceeding a set value, which comprises: There are multiple third difference values not exceeding a set value, and the frequency value of the quantum state control signal corresponding to the third difference value not exceeding a set value is obtained, so that the frequency value of the quantum state control signal corresponding to the highest excited state occupation of the to-be-tested quantum bit is taken as the bit frequency of the to-be-tested quantum bit.

5. The test method of claim 1, wherein, The bit frequency of the to-be-tested quantum bit is obtained based on the frequency value of the quantum state control signal corresponding to the third difference value not exceeding a set value, which comprises: There are multiple third difference values not exceeding a set value, and the frequency value of the quantum state control signal corresponding to the third difference value not exceeding a set value is obtained, so that the frequency value of the quantum state control signal corresponding to the highest excited state occupation of the to-be-tested quantum bit is taken as the bit frequency of the to-be-tested quantum bit. Obtaining data of performing energy spectrum experiment again on the to-be-measured quantum bit, including a plurality of frequency values of the quantum state regulation signal and S 21 Parameter amplitude, wherein the plurality of frequency values of the quantum state regulation signal are contained in an interval containing the first frequency value, and a frequency interval of the plurality of frequency values of the quantum state regulation signal is less than the two times of energy spectrum experiment; In the data of the re-executed energy spectrum experiment, the S 21 The frequency value of the frequency state control signal corresponding to the peak point of the parameter amplitude is the bit frequency of the to-be-measured quantum bit.

6. The test method of claim 5, wherein, The interval is [first frequency value-20MHz, first frequency value+20MHz].

7. The test method of claim 1 or 2, wherein, The acquisition of the at least two energy spectrum experiments, the plurality of frequency values of the quantum state regulation signal correspond to the S 21 Theoretical value of the parameter amplitude, comprising: Based on each time in the energy spectrum experiment, the amplitude of the measured quantum bit is in the ground state, the amplitude of the measured quantum bit is in the excited state, and the quantum state control signal of each frequency value makes the probability of the measured quantum bit in the ground state and the excited state. Obtain the S 21 Theoretical value of the parameter amplitude.

8. The test method of claim 7, wherein, The amplitude of the quantum state control signal corresponding to each frequency value of the quantum state control signal in each energy spectrum experiment is obtained based on the amplitude of the quantum bit to be measured in the ground state, the amplitude of the quantum bit to be measured in the excited state, and the probability of the quantum bit to be measured in the ground state and the excited state in each energy spectrum experiment. 21 The theoretical value of the parameter amplitude includes: According to the formula: S of the readout cavity corresponding to each frequency value of the quantum state control signal in each energy spectrum experiment is obtained 21 a theoretical value of a parameter amplitude, wherein A is the theoretical value, Ae and Ag are amplitudes of the to-be-tested quantum bit in an excited state and in a ground state respectively in each energy spectrum experiment, and Pe and Pg are probabilities of the to-be-tested quantum bit in the excited state and in the ground state respectively under the quantum state control signal of each frequency value.

9. A testing apparatus of a quantum chip, characterized by, The method comprises: An experimental data acquisition module configured to acquire data of at least two energy spectrum experiments performed by a to-be-measured quantum bit on the quantum chip, the data of a single energy spectrum experiment including a plurality of frequency values of a quantum state control signal and a corresponding S 21 Parameter amplitude, in the at least two energy spectrum experiments, the plurality of frequency values of the quantum state control signal are the same, but the frequencies of the read signals are different, and the S 21 Parameter amplitude corresponding to each frequency value in the energy spectrum experiment is different, and the difference between the parameter amplitudes is a first difference value. a theoretical value obtaining module configured to obtain a plurality of frequency values of the quantum state control signal corresponding to S 21 a theoretical value of the parameter amplitude, the S 21 a difference between the theoretical values of the parameter amplitudes is a second difference The bit frequency obtaining module is configured to obtain the third difference value by subtracting the second difference value from the first difference value corresponding to each frequency value of the quantum state control signal, and obtain the bit frequency of the to-be-tested quantum bit based on the frequency value of the quantum state control signal corresponding to the third difference value not exceeding a set value.

10. A readable storage medium, having stored thereon a computer program, characterized in that, The computer program is executed to implement the test method in any one of claims 1-8.

11. A quantum computer, comprising: The test device comprises the test device in claim 9.

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