Frequency determination method and device, electronic equipment and storage medium

Abstract

The embodiment of the invention provides a frequency determination method and device, electronic equipment and a storage medium. According to the scheme, the method comprises the following steps: obtaining a first corresponding relation between coupler frequencies and leakage rates according to operation of at least one resonance type double-quantum logic gate on a first quantum bit and a second quantum bit in a target system under different coupler frequencies; based on the first corresponding relation, the coupler frequency corresponding to the lowest leakage rate is selected as the target frequency, and the target frequency is the frequency of a control signal applied to the adjustable coupler when the first quantum bit and the second quantum bit execute the resonance type double-quantum logic gate operation. Through the technical scheme provided by the embodiment of the invention, the frequency of the control signal applied to the adjustable coupler during the execution period of the resonance type double-quantum logic gate can be determined, so that an observer error is effectively inhibited, and the fidelity of quantum calculation is improved.

Description

Technical Field

[0001] This application relates to the field of quantum computing technology, and in particular to a frequency determination method, apparatus, electronic device, and storage medium. Background Technology

[0002] Quantum computing is a computational paradigm that utilizes the fundamental properties of quantum mechanics to solve problems. By constructing precisely operable quantum physics hardware systems and running quantum computing software to implement quantum algorithms, computational problems can be solved, enabling the application of quantum computing in specific problems or fields.

[0003] During resonant two-quantum logic gate operation, the residual coupling between the two qubits performing the resonant two-quantum logic gate operation and their respective next-neighbor qubits can lead to observer error, affecting the quantum computing results. Summary of the Invention

[0004] The purpose of this application is to provide a frequency determination method, apparatus, electronic device, and storage medium to determine the frequency of the control signal applied to the tunable coupler during the execution of a resonant dual quantum logic gate, thereby effectively suppressing observer error and improving the fidelity of quantum computing. The specific technical solution is as follows:

[0005] This application provides a frequency determination method, the method comprising:

[0006] Based on at least one resonant dual quantum logic gate operation on the first and second qubits in the target system at different coupler frequencies, a first correspondence between coupler frequency and leakage rate is obtained. The target system includes the first qubit, the second qubit, the third qubit, and an adjustable coupler coupling the second qubit and the third qubit. The coupler frequency is the frequency at which a control signal is applied to the adjustable coupler.

[0007] Based on the first correspondence, the coupler frequency corresponding to the lowest leakage rate is selected as the target frequency. The target frequency is the frequency of the control signal applied to the tunable coupler when the first qubit and the second qubit perform the resonant dual quantum logic gate operation.

[0008] Optionally, the method further includes:

[0009] If the resonant dual quantum logic gate operation is performed using the first qubit and the second qubit, a control signal matching the target frequency is applied to the tunable coupler.

[0010] Optionally, if the resonant dual quantum logic gate operation is a CZ gate operation, then the step of obtaining the first correspondence between the coupler frequency and the leakage rate based on at least one resonant dual quantum logic gate operation on the first and second qubits in the target system at different coupler frequencies includes:

[0011] Based on π pulses, the target system is modulated to the first quantum state;

[0012] For each coupler frequency, in the first quantum state, based on at least one resonant dual quantum logic gate operation performed by the first and second qubits in the target system, the quantum state probability corresponding to the second quantum state at that coupler frequency is obtained. The second quantum state is the quantum state corresponding to the target system when leakage occurs between the first qubit and the third qubit in the first quantum state.

[0013] Based on the quantum state probabilities corresponding to the second quantum state at each coupler frequency, a transformation diagram indicating the correspondence between coupler frequency and quantum state probability is generated.

[0014] Optionally, the step of selecting the coupler frequency corresponding to the lowest leakage rate as the target frequency based on the first correspondence includes:

[0015] The coupler frequency corresponding to the minimum quantum state probability in the transformation relationship graph is selected as the target frequency.

[0016] Optionally, if the number of the at least one resonant dual quantum logic gate operations is multiple, the interval between every two resonant dual quantum logic gate operations is a preset duration.

[0017] Optionally, before obtaining the first correspondence between the coupler frequency and the leakage rate based on at least one resonant two-quantum logic gate operation on the first and second qubits in the target system at different coupler frequencies, the method further includes:

[0018] Based on at least one resonant two-qubit logic gate operation on the first and second qubits under different interval durations, a second correspondence between the interval duration and the leakage rate is obtained.

[0019] Based on the second correspondence, the peak finding algorithm is used to determine the interval length corresponding to the highest peak point as the preset duration.

[0020] This application embodiment also provides a frequency determination device, the device comprising:

[0021] The first acquisition module is used to acquire a first correspondence between the coupler frequency and the leakage rate based on at least one resonant dual quantum logic gate operation on the first quantum bit and the second quantum bit in the target system at different coupler frequencies. The target system includes the first quantum bit, the second quantum bit, the third quantum bit, and an adjustable coupler coupling the second quantum bit and the third quantum bit. The coupler frequency is the frequency at which a control signal is applied to the adjustable coupler.

[0022] The selection module is used to select the coupler frequency corresponding to the lowest leakage rate as the target frequency based on the first correspondence relationship. The target frequency is the frequency of the control signal applied to the tunable coupler when the first quantum bit and the second quantum bit perform the resonant dual quantum logic gate operation.

[0023] Optionally, the device further includes:

[0024] An execution module is configured to apply a control signal matching the target frequency to the tunable coupler if the resonant dual quantum logic gate operation is performed using the first qubit and the second qubit.

[0025] Optionally, if the resonant dual quantum logic gate operation is a CZ gate operation, then the first acquisition module is specifically used to modulate the target system to the first quantum state based on the π pulse;

[0026] For each coupler frequency, in the first quantum state, based on at least one resonant dual quantum logic gate operation performed by the first and second qubits in the target system, the quantum state probability corresponding to the second quantum state at that coupler frequency is obtained. The second quantum state is the quantum state corresponding to the target system when leakage occurs between the first qubit and the third qubit in the first quantum state.

[0027] Based on the quantum state probabilities corresponding to the second quantum state at each coupler frequency, a transformation diagram indicating the correspondence between coupler frequency and quantum state probability is generated.

[0028] Optionally, the selection module is specifically used to select the coupler frequency corresponding to the minimum quantum state probability in the transformation relationship graph as the target frequency.

[0029] Optionally, if the number of the at least one resonant dual quantum logic gate operations is multiple, the interval between every two resonant dual quantum logic gate operations is a preset duration.

[0030] Optionally, the device further includes:

[0031] The second selection module is used to obtain a second correspondence between the interval duration and the leakage rate before obtaining a first correspondence between the coupler frequency and the leakage rate by operating at least one resonant dual-qubit logic gate on the first and second qubits of the target system according to different coupler frequencies.

[0032] The determination module is used to determine the interval duration corresponding to the highest peak point as a preset duration based on the second correspondence relationship and using a peak-finding algorithm.

[0033] This application also provides an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0034] Memory, used to store computer programs;

[0035] When a processor executes a program stored in memory, it implements any of the frequency determination method steps described above.

[0036] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements any of the frequency determination method steps described above.

[0037] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to execute any of the frequency determination methods described above.

[0038] Beneficial effects of the embodiments in this application:

[0039] The technical solution provided in this application can obtain a first correspondence between coupler frequency and leakage rate based on at least one resonant dual-quantum logic gate operation on the first and second qubits at different coupler frequencies. Based on this first correspondence, the coupler frequency corresponding to the lowest leakage rate is determined as the target frequency. This determines the frequency of the control signal applied to the tunable coupler between the second and third qubits during the resonant dual-quantum logic gate operation of the first and second qubits. By applying a control signal of the target frequency to this tunable coupler, residual coupling between the first and third qubits is suppressed, thereby suppressing observer error and improving the fidelity of quantum computing.

[0040] Furthermore, since the target frequency is the coupler frequency corresponding to the lowest leakage rate, the residual coupling between the first and second qubits is minimized at the target frequency, which effectively improves the accuracy of the determined target frequency, thereby improving the effectiveness of observer error suppression and enhancing the fidelity of quantum computing.

[0041] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of a first structure of a quantum bit system provided in an embodiment of this application;

[0044] Figure 2 This is a schematic diagram of a first process for a frequency determination method provided in an embodiment of this application;

[0045] Figure 3 This is a second flowchart illustrating the frequency determination method provided in the embodiments of this application;

[0046] Figure 4 This is a third flowchart illustrating the frequency determination method provided in the embodiments of this application;

[0047] Figure 5 A transformation relationship diagram for the first correspondence provided in the embodiments of this application;

[0048] Figure 6 This is a fourth flowchart illustrating the frequency determination method provided in the embodiments of this application;

[0049] Figure 7 A fifth flowchart illustrating the frequency determination method provided in this application embodiment;

[0050] Figure 8 A transformation diagram of the second correspondence provided in the embodiments of this application;

[0051] Figure 9 This is a schematic diagram of a second structure of a quantum bit system provided in an embodiment of this application;

[0052] Figure 10 A schematic diagram of the frequency determination device provided in the embodiments of this application;

[0053] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0055] In related technologies, the two qubits that perform resonant dual quantum logic gate operations on a quantum chip are called gate bits, and the qubit coupled to either gate bit is called an observation bit.

[0056] For ease of understanding, combined with Figure 1 To explain, Figure 1 This is a schematic diagram of a first structure of a quantum bit system provided in an embodiment of this application. Figure 1 The illustrated qubit system includes three qubits on a quantum chip and two tunable couplers, namely the qubit Q. L qubit Q H qubit Q S Coupled qubit Q L and quantum bits Q H Adjustable coupler C G and coupled qubit Q H and quantum bits Q S Adjustable coupler C S Using qubit Q L and quantum bits Q H When performing a resonant two-quantum logic gate operation, the qubit Q L and quantum bits Q H That is, two gate bits, qubit Q S This refers to the observation bit.

[0057] Using the above Figure 1 The quantum bit Q shown L and quantum bits Q H When performing resonant two-quantum logic gate operations, the presence of residual coupling can lead to a decrease in the Q-bit value. L With quantum bit Q S There is quantum state leakage, which leads to observer error. For example, at a certain moment, the quantum bit Q... L and quantum bits Q S The quantum states are |1> and |0>, respectively. Due to observer error, the quantum bit QL and quantum bits Q S The quantum state will transform into |0> and |1>.

[0058] Currently, the main method to reduce the impact of observer error is to increase the detuning between qubits. However, as the number of qubits on a quantum chip continues to increase, errors between the frequency resonance regions corresponding to the qubits are unavoidable, which will make the observer error more pronounced. Furthermore, the leakage into non-computational subspace caused by observer error cannot be corrected by quantum error-correcting codes, which will seriously affect the accuracy of quantum computing results.

[0059] To address the aforementioned problems, embodiments of this application provide a frequency determination method. For example... Figure 2 As shown, Figure 2 This is a schematic flowchart of a first embodiment of the frequency determination method provided in this application. This method can be applied to any electronic device, such as a quantum computer, a quantum computing measurement and control system, etc., and no specific limitation is made to this electronic device. Figure 2 The method shown includes the following steps.

[0060] Step S201: Based on at least one resonant dual quantum logic gate operation on the first and second qubits in the target system at different coupler frequencies, obtain the first correspondence between the coupler frequency and the leakage rate. The target system includes a first qubit, a second qubit, a third qubit, and an adjustable coupler coupling the second and third qubits. The coupler frequency is the frequency at which a control signal is applied to the adjustable coupler.

[0061] Step S202: Based on the first correspondence, select the coupler frequency corresponding to the lowest leakage rate as the target frequency. The target frequency is the frequency of the control signal applied to the tunable coupler when the first quantum bit and the second quantum bit perform resonant dual quantum logic gate operation.

[0062] pass Figure 2 The method shown allows for the determination of a first correspondence between coupler frequency and leakage rate based on at least one resonant dual-quantum logic gate operation on the first and second qubits at different coupler frequencies. Based on this first correspondence, the coupler frequency corresponding to the lowest leakage rate is determined as the target frequency. This determines the frequency of the control signal applied to the tunable coupler between the second and third qubits during the resonant dual-quantum logic gate operation. By applying the target frequency control signal to this tunable coupler, residual coupling between the first and third qubits is suppressed, thereby suppressing observer error and improving the fidelity of quantum computing.

[0063] Furthermore, since the target frequency is the coupler frequency corresponding to the lowest leakage rate, the residual coupling between the first and second qubits is minimized at the target frequency, which effectively improves the accuracy of the determined target frequency, thereby improving the effectiveness of observer error suppression and enhancing the fidelity of quantum computing.

[0064] The specific embodiments described below illustrate the embodiments of this application.

[0065] Regarding step S201 above, that is, based on the operation of at least one resonant dual quantum logic gate on the first quantum bit and the second quantum bit in the target system at different coupler frequencies, a first correspondence between the coupler frequency and the leakage rate is obtained. The target system includes a first quantum bit, a second quantum bit, a third quantum bit, and an adjustable coupler coupling the second quantum bit and the third quantum bit. The coupler frequency is the frequency at which a control signal is applied to the adjustable coupler.

[0066] In this embodiment, the target system may include three qubits: a first qubit, a second qubit, and a third qubit. The first and second qubits can be coupled via a tunable coupler (denoted as the first coupler), and the second and third qubits can be coupled via a tunable coupler (denoted as the second coupler). The first and second qubits can be two gate bits performing the resonant two-quantum logic gate operation, and the third qubit is the observation bit. If the target system is compared with the above... Figure 1 If the qubit system shown is matched, then the first qubit can be Figure 1 The quantum bit Q shown L The second qubit can be Figure 1 The quantum bit Q shown H The third qubit can be Figure 1 The quantum bit Q shown S The first coupler can be an adjustable coupler C. G The second coupler can be an adjustable coupler C. S .

[0067] In the target system described above, the first and third qubits are the second nearest neighbors to each other, meaning that leakage occurs between the first and third qubits.

[0068] The electronic device can perform multiple experiments on the aforementioned target system regarding resonant two-quantum logic gate operations, thereby obtaining the correspondence between the coupler frequency of the second coupler and the leakage rate of the quantum computing results (denoted as the first correspondence) based on the experimental results. During each experiment, the electronic device can adjust the coupler frequency applied to the second coupler, meaning that the coupler frequency is different for each experiment. The method for obtaining the first correspondence is described below and will not be specifically explained here.

[0069] In one alternative embodiment, considering that the leakage during the operation of each resonant dual quantum logic gate is relatively small, which places high demands on the measurement accuracy of the measurement device, the electronic device can perform multiple resonant dual quantum logic gate operations in each experiment, thereby superimposing the leakage corresponding to each resonant dual quantum logic gate operation, which facilitates subsequent measurement and reduces the accuracy requirements of the measurement device.

[0070] In the embodiments of this application, the number of resonant two-quantum logic gate operations performed in each of the above-mentioned experimental processes can be one or more. For example, the number of resonant two-quantum logic gate operations performed in each experimental process can be 20, 25, 30, etc., and the specific number can be a user's empirical value or obtained through multiple experiments. Here, there is no specific limitation on the number of resonant two-quantum logic gate operations performed in each experimental process.

[0071] In an optional embodiment, the above-described resonant dual quantum logic gate operation can be a controlled-Z (CZ) gate operation, a cross-resonance (CR) gate operation, etc. Here, no specific limitation is made to the above-described resonant dual quantum logic gate operation.

[0072] In an optional embodiment, when the number of the above-mentioned at least one resonant dual quantum logic gate operations is multiple, in order to further increase leakage and facilitate leakage measurement, the interval between every two resonant dual quantum logic gate operations can be a preset duration.

[0073] The preset duration can be set based on user experience or through multiple trials. Here, no specific limit is made on the preset duration.

[0074] In an optional embodiment, the first correspondence described above can be represented as a transformation graph between the coupler frequency and the leakage rate (denoted as the first transformation graph). It can also be represented as a fitting function between the coupler frequency and the leakage rate. Here, the representation of the first correspondence is not specifically limited.

[0075] Regarding step S202 above, that is, based on the first correspondence, the coupler frequency corresponding to the lowest leakage rate is selected as the target frequency. The target frequency is the frequency of the control signal applied to the tunable coupler when the first quantum bit and the second quantum bit perform resonant dual quantum logic gate operation.

[0076] In this embodiment, the target frequency can be determined in different ways depending on the representation of the first correspondence. For example, when the first correspondence is represented as the first transformation graph, the electronic device can determine the coupler frequency corresponding to the lowest leakage rate in the first transformation graph as the target frequency. As another example, when the first correspondence is represented as the fitting function, the electronic device can calculate the coupler frequency corresponding to the lowest leakage rate using mathematical solutions, and use this as the target frequency.

[0077] In an optional embodiment, according to the above... Figure 2 The method shown in this application embodiment also provides a frequency determination method. For example... Figure 3 As shown, Figure 3 This is a second flowchart illustrating the frequency determination method provided in an embodiment of this application. Figure 3 The method shown has been augmented with the following step, namely step S203.

[0078] In step S203, if the first and second qubits are used to perform a resonant dual quantum logic gate operation, a control signal matching the target frequency is applied to the tunable coupler.

[0079] In this step, when the electronic device performs the resonant two-quantum logic gate operation using the first and second qubits, a control signal with the target frequency can be applied to the tunable coupler coupling the second and third qubits. That is, a control signal with the target frequency is applied to the tunable coupler coupling the observation bit and the gate bit.

[0080] For ease of understanding, the CZ gate operation described above is used as an example of a resonant dual-quantum logic gate operation. After determining the target frequency through steps S201-S202, the electronic device can generate a periodic flat-top Gaussian wave with the target frequency as a control signal. When performing the CZ gate operation using the first and second qubits, the electronic device can apply this control signal to the second coupler.

[0081] In step S203 above, when the electronic device performs the above-mentioned resonant dual quantum logic gate operation using the first quantum bit and the second quantum bit, it can apply a control signal matching the target frequency to the tunable coupler, thereby using the control signal to counteract the influence of observer error on the resonant dual quantum logic gate operation, and improve the accuracy of the resonant dual quantum logic gate execution and the accuracy of the quantum computing results.

[0082] In addition, compared with the detuning method in related technologies, the embodiments of this application use the method of applying a target frequency to the tunable coupler that couples the observation bit and the gate bit to offset the observer error. This can reduce the probability of frequency collisions between qubits on a large-scale quantum chip to a certain extent, and at the same time, avoid leakage of non-computational subspace.

[0083] In an optional embodiment, if the above resonant dual quantum logic gate operation is a CZ gate operation, then according to the above... Figure 2 The method shown in this application embodiment also provides a frequency determination method. For example... Figure 4 As shown, Figure 4 This is a schematic diagram of a third process for the frequency determination method provided in an embodiment of this application. Figure 4 The method shown refines the above step S201 into the following steps, namely steps S2011-S2013.

[0084] Step S2011: Based on the π pulse, the target system is modulated to the first quantum state.

[0085] The electronic device can initialize the qubits in the target system described above. For example, the electronic device initializes the first, second, and third qubits in the target system to |0>.

[0086] After initialization, the electronic device can apply a π pulse to the gate bits, that is, apply a π pulse to the first and second qubits, thereby modulating the quantum states of the first and second qubits to |1>. At this time, the quantum states corresponding to the first, second, and third qubits are the first quantum state. For example, if the first quantum state is represented in the order of the first, second, and third qubits, then the first quantum state can be represented as |110>.

[0087] In this embodiment, the first quantum state is represented as |1> for the first and second qubits, and |0> for the third qubit. The first quantum state will vary depending on the arrangement of the qubits within it. No specific limitation is made to the first quantum state here.

[0088] Step S2012: For each coupler frequency, in the first quantum state, based on at least one resonant dual quantum logic gate operation performed by the first and second qubits in the target system, obtain the quantum state probability corresponding to the second quantum state at that coupler frequency. The second quantum state is the quantum state corresponding to the leakage between the first and third qubits in the first quantum state of the target system.

[0089] In this step, for each coupler frequency, the electronic device can, when the target system is in the first quantum state mentioned above, that is, when the two gate bits are in |1> and the observation bit is in |0>, perform at least one resonant dual quantum logic gate operation using the first and second quantum bits based on the coupler frequency, thereby reading the quantum state probability of the second quantum state as the quantum state probability corresponding to the second quantum state at that coupler frequency.

[0090] In an optional embodiment, based on the first quantum state described above, the second quantum state can be represented as follows: the quantum state corresponding to the gate bit not coupled to the observation bit (such as the first quantum bit described above) is |0>, the quantum state corresponding to the gate bit coupled to the observation bit (such as the second quantum bit described above) is |1>, and the quantum state of the observation bit is |1>. That is, leakage occurs at the gate bit not coupled to the observation bit, causing a change in the quantum state of the observation bit.

[0091] For ease of understanding, we will take the first quantum state as |110> as an example. The second quantum state can be |011>.

[0092] In the embodiments of this application, the second quantum state will also differ depending on the first quantum state. Here, the second quantum state is not specifically limited.

[0093] Since the aforementioned second quantum state corresponds to the quantum state when leakage occurs between the first and third qubits of the target system in the first quantum state, the quantum state probability of the aforementioned second quantum state can be used to represent the leakage rate. That is, the higher the quantum state probability of the second quantum state, the higher the leakage rate; the lower the quantum state probability of the second quantum state, the lower the leakage rate.

[0094] Step S2013: Based on the quantum state probabilities corresponding to the second quantum state at each coupler frequency, generate a transformation diagram indicating the correspondence between coupler frequency and quantum state probability.

[0095] In this embodiment, since the quantum state probability of the second quantum state can be used to represent the leakage rate, and since there is a corresponding quantum state probability for the second quantum state at each coupler frequency, the quantum state probability corresponding to the second quantum state at each coupler frequency can represent the first correspondence between the coupler frequency and the leakage rate. After obtaining the quantum state probability corresponding to the second quantum state at each coupler frequency, the electronic device can generate a transformation diagram indicating the correspondence between the coupler frequency and the quantum state probability.

[0096] For ease of understanding, combined with Figure 5 To explain, Figure 5 A transformation diagram of the first correspondence provided in the embodiments of this application.

[0097] The electronic device, having obtained the quantum state probabilities corresponding to the second quantum state at each coupler frequency, can map these probabilities to the following values ​​based on the correspondence between coupler frequency and quantum state: Figure 5 The coordinates of the points, such as coordinate point 501. Figure 5 The vertical axis shown represents the leakage rate, which is the quantum state probability corresponding to the second quantum state mentioned above. The electronic device fits the mapped coordinate points, such as the fitted result... Figure 5 The curve shown is 502. The fitted curve obtained is denoted as a transformation graph indicating the correspondence between the above coupler frequency and quantum state probability.

[0098] Through the above steps S2011-S2013, after obtaining the quantum state probability corresponding to the second quantum state at each coupler frequency, the electronic device uses the quantum state probability corresponding to the second quantum state to represent the leakage rate, thereby generating a transformation relationship diagram indicating the correspondence between the coupler frequency and the quantum state probability. This transformation relationship diagram can intuitively reflect the above first correspondence, which is convenient for determining the target frequency based on the transformation relationship diagram in the later stage.

[0099] In the above Figure 4 The embodiments shown only use the CZ gate operation as an example of resonant dual quantum logic gate operation. Other resonant dual quantum logic gates can refer to the above scheme to determine the frequency of the control signal corresponding to the tunable coupler used to couple the observation bit and the gate bit, which will not be specifically described here.

[0100] In an optional embodiment, according to the above... Figure 4 The method shown in this application embodiment also provides a frequency determination method. For example... Figure 6 As shown, Figure 6 This is a schematic diagram of the fourth process for the frequency determination method provided in the embodiments of this application. Figure 6In the method shown, step S202 can be represented as the following steps, namely step S2021.

[0101] Step S2021: Select the coupler frequency corresponding to the minimum quantum state probability in the transformation relationship diagram as the target frequency.

[0102] In this step, since the quantum state probability of the second quantum state can represent the leakage rate, the electronic device can select the coupler frequency corresponding to the minimum quantum state probability in the above-mentioned transformation relationship diagram between the indicated coupler frequency and the quantum state probability to obtain the target frequency.

[0103] For ease of understanding, the above will still be considered. Figure 5 Please provide an explanation. Based on the above... Figure 5 The electronic device can select the coupler frequency corresponding to the coordinate point with the minimum leakage rate on the fitted curve obtained by fitting, that is, the coupler frequency of 6274.7MHz (megahertz) corresponding to position 503 in curve 502 is determined as the target frequency.

[0104] Through the above step S2021, the electronic device can directly determine the coupler frequency corresponding to the minimum quantum state probability as the target frequency according to the above transformation relationship diagram, thereby reducing the complexity of the target frequency determination.

[0105] In an optional embodiment, when the number of the at least one resonant two-quantum logic gate operations is multiple, according to the above... Figure 2 The method shown in this application embodiment also provides a frequency determination method. For example... Figure 7 As shown, Figure 7 This is a fifth flowchart illustrating the frequency determination method provided in this application embodiment. The method includes the following steps.

[0106] Step S701: Based on the operation of at least one resonant two-qubit logic gate on the first and second qubits under different interval durations, obtain the second correspondence between the interval duration and the leakage rate.

[0107] In this step, the electronic device can use different interval durations to perform at least one resonant two-qubit logic gate operation on the first and second qubits of the target system, thereby obtaining the leakage rate corresponding to different interval durations and obtaining a second correspondence between the interval duration and the leakage rate.

[0108] In an optional embodiment, the above-mentioned second correspondence can be represented in the form of a transformation relationship diagram between the interval duration and the leakage rate (denoted as the second transformation relationship diagram). For ease of understanding, combined with... Figure 8 Let's take an example to illustrate. Figure 8This is a transformation diagram of the second correspondence provided in the embodiments of this application.

[0109] Electronic devices can be in accordance with Figure 8 The horizontal axis represents the interval duration. At each interval duration, the leakage rate is obtained through operations using at least one resonant two-quantum logic gate on the first and second qubits. The electronic device can then fit a curve based on the leakage rate at each interval duration, as shown below. Figure 8 The curve shown is 801.

[0110] The method for obtaining the second correspondence mentioned above can refer to the method for obtaining the first correspondence mentioned above. Here, no specific limitation is made on the method for obtaining the second correspondence mentioned above.

[0111] Step S702: Based on the second correspondence, the peak finding algorithm is used to determine the interval duration corresponding to the highest peak point as the preset duration.

[0112] In an optional embodiment, since there may be multiple peak points in the second transformation relationship graph, the electronic device can use a peak-finding algorithm to detect the peaks in the second transformation relationship graph, thereby determining the interval duration corresponding to the highest peak point as a preset duration.

[0113] For ease of understanding, the above will still be used. Figure 8 Let's take an example to illustrate. Electronic devices can use peak-finding algorithms to determine... Figure 8 The position 802 is the highest peak value in curve 801. At this point, the electronic device can determine the interval of the horizontal axis corresponding to the position 802 as the preset duration.

[0114] In this embodiment of the application, the preset duration is the interval duration corresponding to the maximum leakage rate in the second transformation relationship diagram.

[0115] Through the above steps S701-S702, the electronic device can select the interval length corresponding to the maximum leakage rate and determine this interval length as the interval length between every two resonant dual quantum logic gates in the execution process of multiple resonant dual quantum logic gates. This facilitates the realization of coherent co-regeneration of quantum state leakage through the interval length between every two resonant dual quantum logic gates during the target frequency acquisition process, further amplifying the leakage situation and facilitating subsequent measurement, thereby improving the accuracy of the acquired target frequency.

[0116] Step S703: Based on at least one resonant dual quantum logic gate operation on the first and second qubits in the target system at different coupler frequencies, obtain the first correspondence between the coupler frequency and the leakage rate. The target system includes a first qubit, a second qubit, a third qubit, and an adjustable coupler coupling the second and third qubits. The coupler frequency is the frequency at which a control signal is applied to the adjustable coupler.

[0117] In step S703 above, the number of resonant dual quantum logic gate operations performed on the first quantum bit and the second quantum bit can be multiple, and the interval between each two resonant dual quantum logic gate operations is a preset time.

[0118] Step S704: Based on the first correspondence, select the coupler frequency corresponding to the lowest leakage rate as the target frequency. The target frequency is the frequency of the control signal applied to the tunable coupler when the first quantum bit and the second quantum bit perform resonant dual quantum logic gate operation.

[0119] Steps S703-S704 are the same as steps S201-S202.

[0120] In the above embodiments, the frequency determination of the adjustable coupler is explained using only one observation bit as an example. In addition, when the target system includes multiple observation bits, for each observation bit, the electronic device can determine the frequency corresponding to the adjustable coupler used to couple the observation bit and the gate bit according to the above method.

[0121] For ease of understanding, combined with Figure 9 Let's take an example to illustrate. Figure 9 This is a schematic diagram of a second structure of a qubit system provided in an embodiment of this application. The qubit system includes two gates, namely the qubit Q. L and quantum bits Q H And two observation bits, namely Figure 9 The quantum bit Q shown S1 and quantum bits Q S2 .

[0122] To avoid observer error in the Q-qubit L and quantum bits Q H The influence of resonant two-qubit logic gate operations allows electronic devices to separately convert qubits Q... L qubit Q H and quantum bits Q S1 and quantum bits Q L qubit Q H and quantum bits Q S2 As a target system, the qubit Q is determined using the method described above.H and quantum bits Q S1 The frequency of the control signal corresponding to the adjustable coupler (denoted as the third coupler) and the quantum bit Q. H and quantum bits Q S2 The adjustable coupler (denoted as the fourth coupler) controls the frequency of the signal. When using the quantum bit Q... L and quantum bits Q H When performing resonant dual quantum logic gate operations, the electronic device can apply control signals of corresponding frequencies to the third and fourth couplers, thereby suppressing observer error.

[0123] Based on the same inventive concept, and according to the frequency determination method provided in the above embodiments of this application, this application also provides a frequency determination device. For example... Figure 10 As shown, Figure 10 This is a schematic diagram of a frequency determination device provided in an embodiment of this application. The device includes the following modules.

[0124] The first acquisition module 1001 is used to acquire a first correspondence between the coupler frequency and the leakage rate based on at least one resonant dual quantum logic gate operation on the first quantum bit and the second quantum bit in the target system at different coupler frequencies. The target system includes a first quantum bit, a second quantum bit, a third quantum bit, and an adjustable coupler coupling the second quantum bit and the third quantum bit. The coupler frequency is the frequency at which a control signal is applied to the adjustable coupler.

[0125] The selection module 1002 is used to select the coupler frequency corresponding to the lowest leakage rate as the target frequency based on the first correspondence. The target frequency is the frequency of the control signal applied to the tunable coupler when the first quantum bit and the second quantum bit perform resonant dual quantum logic gate operation.

[0126] Optionally, the frequency determination device may further include:

[0127] An execution module is used to apply a control signal matching the target frequency to the tunable coupler if a resonant two-quantum logic gate operation is performed using the first and second qubits.

[0128] Optionally, if the resonant dual quantum logic gate operation is a CZ gate operation, then the first acquisition module 1001 mentioned above can be specifically used to modulate the target system to the first quantum state based on π pulses;

[0129] For each coupler frequency, in the first quantum state, based on at least one resonant two-quantum logic gate operation performed by the first and second qubits in the target system, the quantum state probability corresponding to the second quantum state at that coupler frequency is obtained. The second quantum state is the quantum state corresponding to the leakage between the first and third qubits in the first quantum state of the target system.

[0130] Based on the quantum state probabilities corresponding to the second quantum state at each coupler frequency, a transformation diagram indicating the correspondence between coupler frequency and quantum state probability is generated.

[0131] Optionally, the selection module 1002 mentioned above can be used to select the coupler frequency corresponding to the minimum quantum state probability in the transformation relationship graph as the target frequency.

[0132] Optionally, if there are multiple resonant dual-quantum logic gate operations, the interval between any two resonant dual-quantum logic gate operations is a preset duration.

[0133] Optionally, the frequency determination device may further include:

[0134] The second acquisition module is used to acquire a second correspondence between the interval duration and the leakage rate before acquiring the first correspondence between the coupler frequency and the leakage rate by operating at least one resonant dual-qubit logic gate on the first and second qubits of the target system according to different coupler frequencies.

[0135] The determination module is used to determine the interval duration corresponding to the highest peak point as the preset duration based on the second correspondence relationship and using the peak finding algorithm.

[0136] The apparatus provided in this application allows for the acquisition of a first correspondence between coupler frequency and leakage rate at different coupler frequencies, based on at least one resonant dual-quantum logic gate operation on the first and second qubits. Based on this first correspondence, the coupler frequency corresponding to the lowest leakage rate is determined as the target frequency. This determines the frequency of the control signal applied to the tunable coupler between the second and third qubits during the resonant dual-quantum logic gate operation. By applying the target frequency control signal to this tunable coupler, residual coupling between the first and third qubits is suppressed, thereby suppressing observer error and improving the fidelity of quantum computing.

[0137] Furthermore, since the target frequency is the coupler frequency corresponding to the lowest leakage rate, the residual coupling between the first and second qubits is minimized at the target frequency, which effectively improves the accuracy of the determined target frequency, thereby improving the effectiveness of observer error suppression and enhancing the fidelity of quantum computing.

[0138] Based on the same inventive concept and according to the frequency determination method provided in the above embodiments of this application, this application also provides an electronic device, such as... Figure 11 As shown, it includes a processor 1101, a communication interface 1102, a memory 1103, and a communication bus 1104. The processor 1101, communication interface 1102, and memory 1103 communicate with each other via the communication bus 1104.

[0139] Memory 1103 is used to store computer programs;

[0140] When the processor 1101 executes the program stored in the memory 1103, it implements any of the frequency determination method steps described above.

[0141] The communication bus mentioned in the above electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0142] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0143] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0144] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0145] Based on the same inventive concept, and according to the frequency determination method provided in the above embodiments of this application, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above frequency determination methods.

[0146] Based on the same inventive concept, and according to the frequency determination method provided in the above embodiments of this application, this application also provides a computer program product containing instructions, which, when run on a computer, causes the computer to execute any of the frequency determination methods in the above embodiments.

[0147] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0148] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0149] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, embodiments such as apparatuses, electronic devices, computer-readable storage media, and computer program products are basically similar to the method embodiments, and therefore the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0150] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A frequency determination method, characterized by, The method comprises: obtaining a first correspondence relationship between the coupling frequency and the leakage rate according to at least one resonant-type two-qubit logic gate operation on the first qubit and the second qubit in a target system under different coupling frequencies, the target system comprising the first qubit, the second qubit, a third qubit, and an adjustable coupler coupling the second qubit and the third qubit, the coupling frequency being a frequency of a control signal applied to the adjustable coupler; selecting, based on the first correspondence relationship, a coupling frequency corresponding to the lowest leakage rate as a target frequency, the target frequency being a frequency of a control signal applied to the adjustable coupler when the first qubit and the second qubit perform the resonant-type two-qubit logic gate operation.

2. The method of claim 1, wherein, The method further comprises: if the resonant-type two-qubit logic gate operation is performed using the first qubit and the second qubit, applying a control signal matching the target frequency to the adjustable coupler.

3. The method of claim 1, wherein, If the resonant-type two-qubit logic gate operation is a CZ gate operation, the step of obtaining a first correspondence relationship between the coupling frequency and the leakage rate according to at least one resonant-type two-qubit logic gate operation on the first qubit and the second qubit in a target system under different coupling frequencies comprises: modulating the target system to a first quantum state based on a pi pulse; for each coupling frequency, obtaining a quantum state probability corresponding to a second quantum state under the coupling frequency according to at least one resonant-type two-qubit logic gate operation performed by the first qubit and the second qubit in the target system under the first quantum state, the second quantum state being a quantum state corresponding to the target system when leakage occurs between the first qubit and the third qubit under the first quantum state; generating a transformation relationship diagram indicating the correspondence relationship between the coupling frequency and the quantum state probability according to the quantum state probability corresponding to the second quantum state under each coupling frequency.

4. The method of claim 3, wherein, The step of selecting, based on the first correspondence relationship, a coupling frequency corresponding to the lowest leakage rate as a target frequency comprises: selecting, as the target frequency, a coupling frequency corresponding to the smallest quantum state probability in the transformation relationship diagram.

5. The method of claim 1, wherein, If the number of the at least one resonant-type two-qubit logic gate operation is multiple, the interval duration between each two resonant-type two-qubit logic gate operations is a preset duration.

6. The method of claim 5, wherein, Before obtaining a first correspondence relationship between the coupling frequency and the leakage rate according to at least one resonant-type two-qubit logic gate operation on the first qubit and the second qubit in a target system under different coupling frequencies, the method further comprises: obtaining a second correspondence relationship between the interval duration and the leakage rate according to at least one resonant-type two-qubit logic gate operation on the first qubit and the second qubit under different interval durations; determining, based on the second correspondence relationship, an interval duration corresponding to the highest peak value point as the preset duration by using a peak searching algorithm.

7. A frequency determining device, characterized in that The device comprises: The first obtaining module is configured to obtain a first correspondence between a coupler frequency and a leakage rate according to at least one resonant-type two-qubit logic gate operation on a first qubit and a second qubit in a target system at different coupler frequencies, the target system comprising the first qubit, the second qubit, a third qubit, and an adjustable coupler coupling the second qubit and the third qubit, the coupler frequency being a frequency of a control signal applied to the adjustable coupler; The selecting module is configured to select, based on the first correspondence, a coupler frequency corresponding to a lowest leakage rate as a target frequency, the target frequency being a frequency of a control signal applied to the adjustable coupler when the first qubit and the second qubit perform the resonant-type two-qubit logic gate operation.

8. The apparatus of claim 7, wherein, The apparatus further comprises: The executing module is configured to, if the resonant-type two-qubit logic gate operation is performed by the first qubit and the second qubit, apply a control signal matching the target frequency to the adjustable coupler.

9. An electronic device, comprising: The apparatus comprises a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; The memory is configured to store a computer program; The processor is configured to execute the program stored in the memory to implement the method steps in any of claims 1-6.

10. A computer-readable storage medium, characterized in that, The computer program stored in the computer readable storage medium is executed by the processor to implement the method steps in any of claims 1-6.

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