Quantum bit gate fidelity calibration method and device, electronic equipment and medium

Abstract

The invention provides a quantum bit gate fidelity calibration method and device, electronic equipment and a medium. The quantum bit gate fidelity calibration method comprises the following steps: determining a first quantum bit gate in a plurality of quantum bit gates of a target quantum bit; obtaining a first fidelity of the first quantum bit gate; determining a second quantum bit gate to be calibrated and a first calibration means for calibrating the second quantum bit gate according to the first fidelity; and calibrating the second quantum bit gate based on the first calibration means. According to the embodiment of the invention, the calibration efficiency of the fidelity of the quantum bit gate can be improved. The embodiment of the invention can be applied to various scenes such as quantum computing and quantum communication.

Description

Technical Field

[0001] The present disclosure relates to the field of quantum computing, and in particular to a method, device, electronic device and medium for calibrating the fidelity of a quantum bit gate. Background Art

[0002] The essence of using qubits to perform computing tasks is to perform gate operations on qubits. However, there is often a certain deviation between the calculation results obtained by gate operations and the expected results. Therefore, the qubit gate needs to be calibrated before performing computing tasks to improve the accuracy of quantum computing results. The degree of closeness between the actual calculation results obtained by gate operations and the expected results is the fidelity of the qubit gate. The fidelity of the qubit gate can be improved through calibration.

[0003] In the related art, multiple quantum bit gates need to be adjusted according to a pre-defined calibration path, and the calibration process is relatively fixed, resulting in low calibration efficiency of the quantum bit gate fidelity. Summary of the invention

[0004] The embodiments of the present disclosure provide a method, device, electronic device and medium for calibrating the fidelity of a quantum bit gate, which can improve the calibration efficiency of the fidelity of a quantum bit gate.

[0005] According to one aspect of the present disclosure, a method for calibrating the fidelity of a quantum bit gate is provided, comprising:

[0006] Determining a first qubit gate among a plurality of qubit gates of a target qubit, wherein the plurality of qubit gates are a plurality of qubit gate operations performed based on the target qubit;

[0007] Obtaining a first fidelity of the first quantum bit gate;

[0008] Determining a second qubit gate to be calibrated and a first calibration means for calibrating the second qubit gate according to the first fidelity;

[0009] The second quantum bit gate is calibrated based on the first calibration method.

[0010] According to one aspect of the present disclosure, a device for calibrating the fidelity of a quantum bit gate is provided, comprising:

[0011] A first determining unit, configured to determine a first qubit gate among a plurality of qubit gates of a target qubit;

[0012] A first acquisition unit, configured to acquire a first fidelity of the first quantum bit gate;

[0013] A second determining unit, configured to determine a second qubit gate to be calibrated according to the first fidelity, and determine a first calibration means for calibrating the second qubit gate;

[0014] A calibration unit is used to calibrate the second quantum bit gate based on the first calibration means.

[0015] Optionally, the second determining unit is specifically configured to:

[0016] Determining a first fidelity interval in which the first fidelity lies;

[0017] Determining a second qubit gate to be calibrated according to a first mapping relationship between the first fidelity interval and the qubit gate to be calibrated;

[0018] A first calibration means for calibrating the second quantum bit gate is determined according to a second mapping relationship between the first fidelity interval and the calibration means.

[0019] Optionally, the second determining unit is specifically configured to:

[0020] Obtaining a first mapping relationship table, wherein the first mapping relationship table indicates a first mapping relationship between a fidelity interval and a quantum bit gate to be calibrated;

[0021] According to the first qubit gate and the first fidelity interval, a second qubit gate to be calibrated is obtained by searching in the first mapping relationship table.

[0022] Optionally, the second determining unit is specifically configured to:

[0023] Acquire a second mapping relationship table, wherein the second mapping relationship table indicates a second mapping relationship between the fidelity interval and the calibration means;

[0024] Based on the first quantum bit gate and the first fidelity interval, searching in the second mapping relationship table to obtain a plurality of first candidate calibration means;

[0025] A first calibration approach is determined from the plurality of first candidate calibration approaches.

[0026] Optionally, the second determining unit is specifically configured to:

[0027] Obtaining a second fidelity corresponding to each first candidate calibration means, where the second fidelity is a fidelity obtained by calibrating the second quantum bit gate based on each first candidate calibration means;

[0028] A first calibration method is determined from the plurality of first candidate calibration methods based on the second fidelity corresponding to each of the first candidate calibration methods.

[0029] Optionally, the second determining unit is specifically configured to:

[0030] Obtaining a third fidelity corresponding to the first qubit gate after calibrating the second qubit gate based on each of the first candidate calibration means;

[0031] The first calibration means is determined from the plurality of first candidate calibration means based on the second fidelity and the third fidelity corresponding to each of the first candidate calibration means.

[0032] Optionally, the calibration means calibrates the fidelity of the qubit gate by adjusting one or more of the amplitude, frequency and phase of the radio frequency signal of the target qubit;

[0033] The second determining unit is specifically configured to:

[0034] Calculating the average values ​​of the amplitudes corresponding to the plurality of first candidate calibration means to obtain a first amplitude average value, calculating the average values ​​of the frequencies corresponding to the plurality of first candidate calibration means to obtain a first frequency average value, and calculating the average values ​​of the phases corresponding to the plurality of first candidate calibration means to obtain a first phase average value;

[0035] Determine a second candidate calibration means according to the first amplitude mean, the first frequency mean, and the first phase mean;

[0036] A first calibration means is determined from a calibration means set consisting of the plurality of first candidate calibration means and the second candidate calibration means.

[0037] Optionally, the first mapping relationship table is generated in the following manner:

[0038] Generate multiple data groups based on multiple quantum bit gates and multiple fidelity intervals, wherein the data groups are generated by combining any quantum bit gate with any fidelity interval;

[0039] Obtaining a first fidelity gain corresponding to each data group and the plurality of qubit gates, the first fidelity gain being a difference between the sum of the fidelities of the plurality of qubit gates before and after calibration of the corresponding qubit gate;

[0040] A target quantum bit gate corresponding to each data group is determined according to the first fidelity gain, and a first mapping relationship table is generated according to a mapping relationship between the data group and the target quantum bit gate.

[0041] Optionally, the method further comprises:

[0042] generating a plurality of calibration means based on a combination of a plurality of amplitude values, a plurality of frequency values, and a plurality of phase values;

[0043] After determining the target qubit gate corresponding to each data group according to the first fidelity gain, and generating a first mapping relationship table according to the mapping relationship between the data group and the target qubit gate, the method further includes:

[0044] Obtaining a second fidelity gain corresponding to each data group and the multiple calibration means, the second fidelity gain being a fidelity difference before and after calibrating a corresponding qubit gate using each calibration means, the corresponding qubit gate being a target qubit gate that has a mapping relationship with each data group in the first mapping relationship table;

[0045] A candidate calibration means corresponding to each data group is determined according to the second fidelity gain, and a second mapping relationship table is generated according to a mapping relationship between the data group and the candidate calibration means.

[0046] Optionally, the quanta gate fidelity calibration device further comprises:

[0047] A cyclic calibration unit is used to determine that the second qubit gate is the current qubit gate, and cyclically execute the following steps:

[0048] Performing fidelity testing on the plurality of quantum bit gates;

[0049] When it is detected that the fidelity of a qubit gate among the multiple qubit gates is less than a predetermined fidelity value, determining a qubit gate to be calibrated and a calibration means for calibrating the qubit gate to be calibrated according to the fidelity of the current qubit gate, calibrating the qubit gate to be calibrated based on the calibration means, and updating the current qubit gate based on the qubit gate to be calibrated;

[0050] When the fidelity of the plurality of quantum bit gates is greater than or equal to a predetermined fidelity value, the loop step is terminated.

[0051] Optionally, the first acquiring unit includes:

[0052] Performing an operation corresponding to the first quantum bit gate on the target quantum bit, and obtaining an actual state of the target quantum bit;

[0053] The first fidelity of the first qubit gate is determined based on a difference between the actual state and a desired state.

[0054] Optionally, the first determining unit includes:

[0055] Obtaining an initial fidelity value of each qubit gate in a plurality of qubit gates of a target qubit;

[0056] The quantum bit gate with the highest initial fidelity value is determined to be the first quantum bit gate.

[0057] According to one aspect of the present disclosure, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the method for calibrating the fidelity of a quantum bit gate as described above when executing the computer program.

[0058] According to one aspect of the present disclosure, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the method for calibrating the fidelity of a quantum bit gate as described above is implemented.

[0059] According to one aspect of the present disclosure, a computer program product is provided, which includes a computer program, and the computer program is read and executed by a processor of a computer device, so that the computer device executes the method for calibrating the fidelity of a quantum bit gate as described above.

[0060] In the disclosed embodiment, an initial first qubit gate is determined from a plurality of qubit gates of a target qubit. The first fidelity of the first qubit gate is obtained, and the second qubit gate to be calibrated next and the first calibration means for calibrating the second qubit gate are determined based on the first fidelity. The second qubit gate is calibrated using the first calibration means. In this way, the qubit gate fidelity calibration method provided in the disclosed embodiment can dynamically determine the next qubit gate to be calibrated and the corresponding calibration means based on the fidelity of the current qubit gate, thereby avoiding the limitation of the fixed order calibration on the qubit gates to be calibrated and the calibration effect in the related art, thereby improving the calibration efficiency of the qubit gate fidelity.

[0061] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or understood by practicing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The accompanying drawings are used to provide further understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation on the technical solution of the present disclosure.

[0063] Figure 1 is a system architecture diagram of a system to which a method for calibrating the fidelity of a quantum bit gate according to an embodiment of the present disclosure is applied;

[0064] Figure 2A It is a schematic diagram of calibrating multiple qubit gates using a fixed calibration path;

[0065] Figure 2B is a schematic diagram of a calibration path for calibrating multiple qubit gates according to a qubit gate fidelity calibration method according to an embodiment of the present disclosure;

[0066] Figure 3 is an overall flow chart of a method for calibrating the fidelity of a quantum bit gate according to an embodiment of the present disclosure;

[0067] Figure 4 It is a schematic diagram of the entanglement of a quantum bit unit with an adjacent quantum bit unit;

[0068] Figure 5 yes Figure 3 A specific flow chart of step 310;

[0069] Figure 6 yes Figure 3 A specific flow chart of step 320 in FIG.

[0070] Figure 7 yes Figure 3 A specific flow chart of step 330;

[0071] Figure 8 yes Figure 7 A specific flow chart of step 320 in FIG.

[0072] Fig. 9 is a specific flow chart for generating a first mapping relationship table;

[0073] Fig.10 It is a schematic diagram of the change in the fidelity of multiple qubit gates after calibrating a qubit gate;

[0074] Fig.11 yes Figure 7 A specific flow chart of step 730;

[0075] Fig.12 is Fig. 9 A specific flow chart of generating a second mapping relationship table based on the

[0076] Fig.13 yes Figure 7 Another specific flow chart of step 730;

[0077] Fig.14 yes Fig.11 A specific flow chart of step 1130;

[0078] Fig.15 yes Fig.11 Another specific flow chart of step 1130;

[0079] Fig.16 yes Fig.14A specific flow chart of step 1425;

[0080] Fig.17 is a flow chart for determining a first calibration means;

[0081] Fig.18 is Figure 3 A specific flow chart for calibrating multiple qubit gates based on ;

[0082] Fig.19 is a detailed diagram of the overall implementation of the method for calibrating the fidelity of a quantum bit gate according to an embodiment of the present disclosure;

[0083] Fig. 20 is a block diagram of a device for calibrating the fidelity of a quantum bit gate according to an embodiment of the present disclosure;

[0084] Fig.21 An embodiment according to the present disclosure is shown. Figure 3 Computer architecture diagram showing the method for calibrating the fidelity of quantum bit gates. DETAILED DESCRIPTION

[0085] In order to make the purpose, technical solution and advantages of the present disclosure more clear, the present disclosure is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are not used to limit the present disclosure.

[0086] Before further describing the embodiments of the present disclosure in detail, the nouns and terms involved in the embodiments of the present disclosure are described. The nouns and terms involved in the embodiments of the present disclosure are subject to the following interpretations:

[0087] Quantum computing: Quantum computing is a computing method designed using the principles of quantum mechanics. The biggest difference between it and traditional computing is that it uses quantum bits (qubits) instead of traditional binary bits (bits) for computing. Quantum bits have different properties from traditional binary bits, the most important of which is that they can be in multiple states at the same time. Take the famous "Schrödinger's cat" as an example. A cat is locked in a sealed container containing a small amount of radium and cyanide. There is a probability that radium will decay. If radium decays, it will trigger a mechanism to break the bottle containing cyanide, and the cat will die; if radium does not decay, the cat will survive. According to the theory of quantum mechanics, since radioactive radium is in a superposition of two states: decay and no decay, the cat should be in a superposition state of a dead cat and a live cat. This cat that is both dead and alive is the so-called "Schrödinger's cat". However, it is impossible for a cat to be both dead and alive, so the result must be known after the container is opened. However, precisely because quantum bits can represent two states at the same time and carry more information, more data operations can be completed with the same number of quantum bits than classical computing. Therefore, quantum computing has greatly improved computer processing speed.

[0088] Quantum: The quantum in “quantum computing” refers to the smallest discrete unit a system can use to compute an output.

[0089] Quantum bit: is the basic unit of information in quantum computing. The role played by qubits in quantum computing is similar to that played by bits in traditional computing, but their behavior is very different. Classical bits are binary and can only store 0 or 1 bits, but qubits can store a superposition of all possible states, that is, a superposition of state |0> and state |1>, thus greatly improving computer processing speed. A single qubit can also be called a qubit unit.

[0090] Entanglement: Entanglement is the ability of qubits to correlate with each other. When qubits are entangled, they form a system and influence each other. By adding and entangling more qubits in quantum computing, quantum computers can calculate exponentially more information and solve more complex problems.

[0091] System architecture and scenario description of the application of the embodiments of the present disclosure

[0092] Figure 1 This is a system architecture diagram used in the method for calibrating the fidelity of quantum bit gates according to an embodiment of the present disclosure, which includes a quantum chip 110, a dilution refrigerator 120, a control device 130, a computer 140, and the like.

[0093] The quantum chip 110 is a circuit that acts on a physical quantum bit, and is used to control the quantum bit to perform quantum computing tasks, and is also used to apply different calibration methods to the quantum bit gate when calibrating the fidelity of the quantum bit gate. A large number of quantum bit units are distributed in the quantum chip 110.

[0094] The dilution refrigerator 120 is used to provide an extremely low temperature environment for the quantum chip 110 , which helps to suppress thermal noise in the quantum chip 110 and improve the performance of the quantum chip.

[0095] The control device 130 is used to control the quantum chip 110 to perform quantum computing tasks. The control device 130 can be an electronic control system or a microwave control system. The computer 140 is used to send control instructions to the control device 130. For example, the compiled quantum program is compiled by the computer 140 to generate instructions and sent to the control device 130. The control device 130 then converts the above instructions into electronic or microwave control signals and transmits them to the quantum chip 110, which controls the quantum bits. The computer 140 can be a classical computer or a quantum computer, or a hybrid execution environment of a classical computer and a quantum computer.

[0096] The embodiments of the present disclosure can be applied in a variety of scenarios, such as a scenario where multiple quantum computing tasks are queued for execution.

[0097] When the computer 140 receives a quantum computing task, it is necessary to determine the quantum bit that can perform the task among the large number of quantum bits in the quantum chip 110. It can be seen that for different quantum computing tasks, the quantum bits used in the quantum chip 110 may be different. Therefore, before the computer 140 executes each quantum computing task, the fidelity of the multiple quantum bit gates corresponding to the corresponding quantum bits can be calibrated to improve the accuracy of the execution results of the quantum computing task. If the computer 140 receives multiple quantum computing tasks, the fidelity of the multiple quantum bit gates corresponding to the quantum bits used in each quantum computing task can be calibrated in turn. If the fidelity calibration of the quantum bit gate of a quantum computing task takes a long time, it will also delay the execution of other quantum computing tasks, which undoubtedly brings challenges to the calibration efficiency of the quantum bit gate fidelity.

[0098] In the related art, for a quantum computing task, the process of calibrating the fidelity of multiple qubit gates corresponding to the qubits used in the quantum computing task is pre-set. Specifically, a directed acyclic graph (DAG) can be used to represent the pre-set qubit gate fidelity calibration process, where the nodes in the DAG represent a qubit gate and a corresponding fidelity calibration target, and the edges in the DAG represent the dependency between the nodes, that is, the fidelity calibration of the qubit gate in the previous node reaches the corresponding fidelity calibration target before entering the next node to perform the fidelity calibration of the qubit gate of the next node. For example Figure 2A As shown, there can be four qubit gates that need to be calibrated, namely, gate I, gate X, gate Y, and gate H. When the fidelity of gate X reaches 80%, according to the predetermined path, the fidelity of gate Y is calibrated by calibration means A to make the fidelity of gate Y reach 85%. After the fidelity of gate Y reaches 85%, the fidelity of gate H is calibrated by calibration means B to make the fidelity of gate H reach 90%. After the fidelity of gate H reaches 90%, the fidelity of gate I is calibrated by calibration means C to make the fidelity of gate I reach 85%. Similarly, in order, the fidelity of gate X is increased to 90% by calibration means D, the fidelity of gate Y is increased to 95% by calibration means E, the fidelity of gate X is increased to 95% by calibration means F, the fidelity of gate I is increased to 95% by calibration means G, and the fidelity of gate H is increased to 95% by calibration means H. Using such a fixed calibration path and calibration method to perform calibration does not allow the calibration process to explore other paths with better calibration effects. Figure 2B As shown, when the fidelity of gate X reaches 80%, the fidelity of gate H can be directly calibrated to 95% through calibration means M; when the fidelity of gate H reaches 95%, the fidelity of gate X can be calibrated to 95% through calibration means N; when the fidelity of gate X reaches 95%, the fidelity of gate I can be calibrated to 95% through calibration means G; when the fidelity of gate I reaches 95%, the fidelity of gate Y can be calibrated to 95% through calibration means P. Figure 2A The calibration path shown requires a total of 8 calibrations. Figure 2B Only four calibrations are required in the calibration path. Figure 2BThe calibration efficiency of the calibration path is higher, but the solution of the related art does not consider this calibration path with better calibration effect, and the calibration efficiency is low. When faced with a scenario where multiple quantum computing tasks are queued for execution, it is impossible to quickly calibrate each quantum computing task, which affects the execution efficiency of the quantum computing tasks. Moreover, the method of calibrating the fidelity of quantum bit gates based on DAG in the related art may also have a situation where the fidelity of the quantum bit gate in the current node cannot be calibrated to reach the fidelity target set in the node. In this case, since the task of the current node has not been completed, the next node that depends on this node cannot perform the corresponding calibration work, which causes the calibration process to be stuck, which greatly reduces the calibration efficiency of the quantum bit gate fidelity.

[0099] The disclosed embodiment can determine the next qubit gate to be calibrated and the calibration method to be used based on the fidelity of the current qubit gate. Figure 2A and Figure 2B If the current qubit gate is gate X and its fidelity is 80%, the one that can bring the best calibration effect is determined from gates I, Y and H as the next qubit gate to be calibrated, and the calibration method that can improve the fidelity of the next qubit gate to be calibrated the most is determined from multiple calibration methods. Figure 2A In the fixed path in, when the fidelity of gate X reaches 80%, the calibration means A must be used to calibrate gate Y so that the fidelity of gate Y reaches 85%. However, through the embodiments of the present disclosure, it can be found that when the fidelity of gate X reaches 80%, the effect of calibrating gate H is better, and the fidelity of gate H can be directly increased to 95% by using the calibration means M. Therefore, the embodiments of the present disclosure greatly improve the calibration efficiency of the fidelity of quantum bit gates. In the scenario where multiple quantum computing tasks are queued for execution, the execution progress of multiple quantum computing tasks is accelerated by reducing the calibration time required for each quantum computing task.

[0100] General description of the disclosed embodiments

[0101] According to one embodiment of the present disclosure, a method for calibrating the fidelity of a quantum bit gate is provided.

[0102] The qubit gate controls the state of the qubit by applying a radio frequency modulation signal to the qubit to achieve gate operation. The state of the qubit is a superposition of state |0> and state |1>, with a probability of α corresponding to state |0> and a probability of β corresponding to state |1>. By applying different radio frequency modulation signals to change the superposition state of the qubit, the values ​​of α and β change accordingly, but no matter how they change, the two satisfy α 2 +β 2=1. Using qubits to perform quantum computing tasks is essentially to perform a large number of gate operations on qubits according to the quantum computing tasks. There are many types of qubit gates, such as I, X, Y, and H. Different qubit gates apply different RF modulation signals, and the states of the qubits after the gate operation are also different. For example, the X gate will swap the probabilities of the qubit state |0> and state |1>, that is, the probability corresponding to state |0> becomes β, and the probability corresponding to state |1> becomes α. The H gate will change the probability corresponding to the qubit state |0> to The probability corresponding to state |1> becomes The superposition state of a qubit is the expected state after gate operation. However, in practice, the state obtained after gate operation on a qubit often cannot reach the expected state. Therefore, fidelity is used to measure the difference between the actual state and the expected state after a qubit gate operation. The higher the fidelity, the smaller the difference. The process of calibrating the fidelity of a qubit gate is the process of improving the fidelity of the qubit gate.

[0103] When calibrating the fidelity of multiple qubit gates, it is necessary to consider the calibration order and the calibration means used. In related technologies, the calibration order and calibration means used for multiple qubit gates are fixed, and the amount of fidelity improvement after each calibration is also fixed. This prevents the exploration of calibration paths and corresponding calibration means with better calibration effects during the calibration process, reducing calibration efficiency.

[0104] like Figure 3 As shown, the method for calibrating the fidelity of a quantum bit gate according to an embodiment of the present disclosure includes:

[0105] Step 310: determining a first qubit gate among a plurality of qubit gates of a target qubit;

[0106] Step 320: Obtain a first fidelity of a first quantum bit gate;

[0107] Step 330: Determine a second qubit gate to be calibrated and a first calibration means for calibrating the second qubit gate according to the first fidelity;

[0108] Step 340: Calibrate the second quantum bit gate based on the first calibration method.

[0109] Steps 310 to 340 are described in detail below.

[0110] Detailed description of step 310

[0111] For a quantum computing task, it is necessary to select a quantum bit unit that can perform the quantum computing task from a large number of quantum bit units in the quantum chip 110. Multiple quantum bit units form a quantum bit network by making two adjacent quantum bit units correlated with each other. Two correlated quantum bit units will be entangled and affect each other. When performing quantum computing, it is necessary to use each quantum bit unit in the quantum bit network to perform operations, and it is also necessary to use the entanglement between two correlated quantum bit units to perform operations. Figure 4 As shown, qubit unit A is entangled with qubit unit B, and qubit unit B is entangled with qubit unit C. When performing quantum computing, qubit unit A, qubit unit B, qubit unit C, the entanglement of qubit units A and B, and the entanglement of qubit units B and C need to be gated through multiple qubit gates respectively. Therefore, it is necessary to calibrate the fidelity of the gate operation for the entanglement between each qubit unit and the qubit unit. Therefore, in the disclosed embodiment, the target qubit can be a qubit unit or the entanglement between qubit units.

[0112] The multiple qubit gates of the target qubit are multiple qubit gate operations performed on the target qubit. The difference between the entanglement between qubit units and qubit units is that different qubit gates are applicable to the two. If the target qubit is a qubit unit, the above-mentioned gates I, X, Y and H can be used to perform gate operations on the target qubit, then these four gates are the qubit gates to be calibrated for the target qubit. If the target qubit gate is the entanglement between qubit units, the gate operation needs to consider the states of the two qubit units. Assuming there are two adjacent qubit units A and B, the probability corresponding to the state of A |0> is α A , the probability corresponding to state |1> is β A , the probability corresponding to the state |0> of B is α B , the probability corresponding to state |0> is β B Assume there are two gate operations, gate M and gate N. Gate M will convert α A α B Convert to alpha A β B , and α A β B Convert to beta A α B , β A α B Convert to beta A β B , β A β B Convert to alpha A α B Gate N will convert αA α B Convert to (α A α B +α A β B +β A α B +β A β B ) / 4, and α A β B Convert to (α A α B +α A β B +β A α B +β A β B ) / 4, and β A α B Convert to (α A α B +α A β B +β A α B +β A β B ) / 4, and β A β B Convert to (α A α B +α A β B +β A α B +β A β B ) / 4.

[0113] The first qubit gate may be an initial qubit gate determined from a plurality of qubit gates. Since the plurality of qubit gates of the target qubit all need to be calibrated, any qubit gate may be used as the first qubit gate. Therefore, the first qubit gate may be determined by random selection from the plurality of qubit gates of the target qubit.

[0114] In another embodiment, Figure 5 As shown, determining a first quantum bit gate among multiple quantum bit gates of a target quantum bit includes:

[0115] Step 510: Obtain an initial fidelity value of each qubit gate in a plurality of qubit gates of a target qubit;

[0116] Step 520: Determine the quantum bit gate with the highest initial fidelity value as the first quantum bit gate.

[0117] In this embodiment, the first qubit gate is determined based on the initial fidelity values ​​of multiple qubit gates. The initial fidelity value is the fidelity value of the qubit gate when it has not been calibrated. The fidelity of the qubit gate is mainly affected by the noise interference of the external environment. Therefore, if the external environment is stable, the fidelity value of the uncalibrated qubit gate will not fluctuate too much. Therefore, the initial fidelity value of the qubit gate can be experimentally determined in a stable environment in advance so that it can be called at any time when needed. For example, after experiments, the initial fidelity value of gate X is generally stable at 80%, with a slight fluctuation of 1%; the initial fidelity value of gate Y is generally stable at 85%, with a slight fluctuation of 1%. Then, 80% can be used as the initial fidelity value of gate X, and 85% can be used as the initial fidelity value of gate Y. This can improve the efficiency of obtaining the initial fidelity value of each qubit gate.

[0118] Since the calibration process of the qubit gate fidelity is a process of spiraling the fidelity of multiple qubit gates, the qubit gate with the highest initial fidelity value is used as the first qubit gate, which can set a higher baseline for the calibration process of the qubit gate fidelity, thereby improving the efficiency of the qubit gate fidelity calibration. Therefore, in the disclosed embodiment, after obtaining the initial fidelity value of each qubit gate, the qubit gate with the highest initial fidelity value can be set as the first qubit gate to further improve the calibration efficiency of the qubit gate fidelity.

[0119] Detailed description of step 320

[0120] In step 320, a first fidelity of a first quantum bit gate is obtained.

[0121] In the embodiment of steps 510-520, the initial fidelity value of the quantum bit gate can be determined experimentally in a stable environment in advance. If the first fidelity of the first quantum bit gate is obtained based on the embodiment of steps 510-520, the initial fidelity value corresponding to the first quantum bit gate can be directly used as the first fidelity when the first quantum bit gate is determined. If the first quantum bit gate is obtained by random extraction, the initial fidelity value of the first quantum bit gate stored in advance can also be retrieved as the first fidelity. The advantage of using the initial fidelity of the first quantum bit gate as the first fidelity is that the first fidelity can be obtained faster and more efficiently.

[0122] However, in the subsequent steps, the second qubit gate and the first calibration means need to be determined based on the first fidelity, so the accuracy of the first fidelity is very important. Figure 6 As shown, step 320 includes:

[0123] Step 610: Execute the operation corresponding to the first quantum bit gate on the target quantum bit, and obtain the actual state of the target quantum bit;

[0124] Step 620: Determine a first fidelity of the first qubit gate based on a difference between the actual state and the expected state.

[0125] The first fidelity represents the difference between the actual state of the target qubit and the expected state after the operation corresponding to the first qubit gate is performed on the target qubit. The expected state refers to the state of the target qubit after the operation corresponding to the first qubit gate is performed on the target qubit in an ideal environment without any noise and interference. For example, the first qubit gate is gate X. Performing gate X on the target qubit will swap the probabilities of the two states |0> and |1>, generating a new superposition state. In other words, if the probability of the state |0> of the target qubit is 4 / 5, and the probability of the state |1> is 3 / 5, then after the operation corresponding to gate X is performed on the target qubit, the expected state of the target qubit is state |0> with a probability of 3 / 5, and state |1> with a probability of 4 / 5. However, due to interference in the actual computing environment, the expected state often cannot be achieved after the first qubit gate is executed. For example, after executing gate X, the actual state of the target qubit is state |0> with a probability of 3 / 4, and state |1> with a probability of 4 / 5. This shows that there is a difference between the actual state and the expected state.

[0126] The first fidelity of the first qubit gate is determined based on the difference between the actual state and the expected state as shown in Formula 1:

[0127] F(ε,μ)=Tr[ε(|0><1|)μ(|0><1|)] (Formula 1).

[0128] In Formula 1, ε is the actual state of the target quantum bit after the gate operation of the first quantum bit gate; μ is the expected state; F is the difference between the actual state and the expected state, that is, the fidelity; Tr refers to the trace operation of the actual state and the expected state to obtain the first fidelity of the first quantum bit gate.

[0129] This embodiment obtains the actual state by performing the operation corresponding to the first quantum bit gate on the target quantum bit, and then determines the first fidelity based on the difference between the actual state and the expected state, thereby ensuring that the first fidelity can reflect the accuracy of the gate operation performed by the current first quantum bit gate, thereby improving the accuracy of obtaining the first fidelity.

[0130] Detailed description of step 330

[0131] In step 330, a second qubit gate to be calibrated and a first calibration means for calibrating the second qubit gate are determined based on the first fidelity.

[0132] The qubit gate performs gate operations on the qubit by applying a radio frequency modulation signal to the qubit. The calibration method for calibrating the qubit gate is to adjust the radio frequency modulation signal of the qubit so that the gate operation result of the qubit is close to the expected state. For a qubit, multiple qubit gates are correlated, and the fidelity of a qubit gate may affect the calibration effect of the qubit gate that is calibrated later. For example, only when the fidelity of gate X reaches 85%, can a better calibration effect be obtained by calibrating gate H. If the qubit gate to be calibrated is randomly selected, it may result in poor calibration results, and it may also happen that the fidelity of one qubit gate is improved, but the fidelity of other qubit gates is reduced. Therefore, it is necessary to consider the correlation between qubit gates, and determine the second qubit gate to be calibrated based on the fidelity of the first qubit gate.

[0133] The first calibration means for calibrating the second qubit gate is also related to the first fidelity of the first qubit gate. This is because the effect of calibrating other qubit gates can only be achieved when the first fidelity of the first qubit gate reaches a predetermined standard. If the calibration means are randomly selected, the fidelity of other qubit gates may decrease. That is, the second qubit gate determined according to the first fidelity and the first calibration means for calibrating the second qubit gate are both choices that can improve the fidelity of the overall qubit gate based on the first fidelity, and are generally the choices that maximize the improvement of the fidelity of the overall qubit gate.

[0134] In some embodiments, the second qubit gate and the first calibration means can be determined according to the first fidelity by combining the qubit gates other than the first qubit gate with a plurality of calibration means, calibrating the qubit gates in the combination using the calibration means in the combination, obtaining the fidelity increment before and after the calibration, and taking the qubit gate in the combination with the largest fidelity increment as the second qubit gate, and taking the calibration means therein as the first calibration means. For example, the qubit gates other than the first qubit gate include: gate X, gate Y, and the calibration means include: calibration means A, calibration means B, and calibration means C, then after the combination, (gate X, calibration means A), (gate X, calibration means B), (gate X, calibration means C), (gate Y, calibration means A), (gate Y, calibration means B), and (gate Y, calibration means C) are obtained. Calibration means A is used to calibrate gate X, and the fidelity before and after calibration increases from 75% to 90%, and the fidelity increment is 15%; calibration means B is used to calibrate gate X, and the fidelity before and after calibration decreases from 75% to 70%, and the fidelity increment is -5%, and so on. Obtain the fidelity increment before and after each combination calibration. If the fidelity increment obtained after calibrating gate X using calibration method A is the largest, then the second quantum gate is gate X, and the first calibration method is calibration method A.

[0135] Since a large number of qubit gate operations need to be performed on the target qubit, and there are many calibration methods for calibration, a large number of combinations of qubit gates and calibration methods will be generated. If the best calibration effect is selected from them after testing one by one, the efficiency is low. Therefore, the second qubit gate and the first calibration method can be determined based on the first fidelity based on a predetermined preset relationship. In one embodiment, Figure 7 As shown, step 330 includes:

[0136] Step 710: Determine a first fidelity interval in which the first fidelity is located;

[0137] Step 720: Determine a second qubit gate to be calibrated according to a first mapping relationship between the first fidelity interval and the qubit gate to be calibrated;

[0138] Step 730: Determine a first calibration means for calibrating the second quantum bit gate according to a second mapping relationship between the first fidelity interval and the calibration means.

[0139] In this embodiment, the fidelity is divided according to the interval. The first fidelity interval can be divided with a step size of 5%, including: [0, 5%), [5%, 10%), ..., [90%, 95%), [95%, 100%). Each fidelity interval corresponds to the second quantum bit gate to be calibrated, and also corresponds to the first calibration method. If the first fidelity is 81%, then the first fidelity interval is [80%, 85%).

[0140] After determining the first fidelity interval in which the first fidelity is located, the second qubit gate to be calibrated is determined according to the first mapping relationship between the first fidelity interval and the qubit gate to be calibrated. The first mapping relationship is determined in advance so that the second qubit gate can be found directly according to the first fidelity interval. The first mapping relationship can be stored in a variety of forms such as a mapping relationship table and text.

[0141] In one embodiment, Figure 8 As shown, step 720 includes:

[0142] Step 810: Obtain a first mapping relationship table;

[0143] Step 820: According to the first qubit gate and the first fidelity interval, a second qubit gate to be calibrated is obtained by searching in the first mapping relationship table.

[0144] In this embodiment, the first mapping relationship is stored in the form of a mapping relationship table. The first mapping relationship table indicates the first mapping relationship between the combination of the qubit gate and the fidelity interval and the qubit gate to be calibrated. Table 1 shows an example of the first mapping relationship table.

[0145] Quantum bit gates and fidelity intervals The qubit gate to be calibrated Door X [80%, 85%) Door Y Door Y[80%,85%) Door H Door H [80%, 85%) Gate I Gate I [80%, 85%) Door X Door X [85%, 90%) Door H Door Y[85%,90%) Door X …… …… Gate H [95%, 100%) Door Y Gate I [95%, 100%) Door H

[0146] Table 1

[0147] Based on the first mapping relationship table in Table 1, when the first quantum bit gate is gate X and the first fidelity interval is [80%, 85%), the quantum bit gate to be calibrated is gate Y.

[0148] The first mapping relationship table eliminates the need to traverse all quantum bit gates each time a quantum bit gate to be calibrated is determined, thereby improving the efficiency of determining the second quantum bit gate based on the first fidelity interval of the first quantum bit gate.

[0149] The process of generating the first mapping relationship table is to determine the quantum bit gate to be calibrated with the best calibration effect based on the combination of the quantum bit gate and the fidelity interval, and generate the first mapping relationship.

[0150] In one embodiment, Fig. 9As shown, the first mapping relationship table is generated in the following manner:

[0151] Step 910: Generate multiple data groups based on multiple quantum bit gates and multiple fidelity intervals, where the data groups are generated by combining any quantum bit gate with any fidelity interval;

[0152] Step 920: Obtain a first fidelity gain corresponding to each data group and a plurality of quantum bit gates;

[0153] Step 930: determine the target quantum bit gate corresponding to each data group according to the first fidelity gain, and generate a first mapping relationship table according to the mapping relationship between the data group and the target quantum bit gate.

[0154] In step 910, each of the plurality of qubit gates is combined with each fidelity interval to obtain a plurality of data groups. For example, the qubit gates include: gate X and gate Y, and the fidelity intervals include: [85%, 90%), [90%, 95%), and [95%, 100%), then the generated data groups include: (gate X, [85%, 90%)), (gate X, [90%, 95%)), (gate X, [95%, 100%)), (gate Y, [85%, 90%)), (gate Y, [90%, 95%)) and (gate Y, [95%, 100%)).

[0155] For each data group, obtain the first fidelity gain corresponding to multiple qubit gates other than the qubit gates in the data group. The first fidelity gain is the difference between the sum of the fidelities of the multiple qubit gates before and after the corresponding qubit gate is calibrated. The corresponding qubit gate refers to each of the multiple qubit gates other than the qubit gates in the data group. For each qubit gate, obtain the difference between the sum of the fidelities of the multiple qubit gates before and after the calibration as the first fidelity gain. For example Fig.10 As shown, the qubit gate includes: gate X, gate Y and gate H. When determining the target qubit gate of the data group (gate X, [85%, 90%)), the first fidelity gain of gate Y and gate H is obtained respectively. The first fidelity gain of gate Y refers to the difference between the sum of the fidelities of gates X, Y and H and the sum of the fidelities before calibration after calibrating gate Y. If the fidelities of gates X, Y and H are 86%, 80% and 81% respectively before calibrating gate Y, and the fidelities of the three are 84%, 83% and 82% respectively after calibration. Then the first fidelity gain of gate Y is (84%+83%+82%)-(86%+80%+81%)=2%. Similarly, the first fidelity gain of gate H refers to the difference between the sum of the fidelities of gates X, Y and H and the sum of the fidelities before calibration after calibrating gate H.

[0156] The reason for using the difference in the sum of the fidelities of multiple qubit gates before and after calibration as the first fidelity gain is that calibrating the fidelity of a qubit gate will affect the fidelity of other qubit gates. Even if the fidelity of the calibrated qubit gate before and after calibration is improved to a high level, the fidelity of other qubit gates may decrease. Therefore, by using the difference in the sum of the fidelities of multiple qubit gates before and after calibration as the first fidelity gain, the target qubit gate with the best overall calibration effect can be found from multiple qubit gates.

[0157] After obtaining the first fidelity gain corresponding to each qubit gate except the qubit gate in the data group, the target qubit gate corresponding to the data group is determined according to the first fidelity gains of the multiple qubit gates. The higher the first fidelity gain corresponding to the qubit gate, the higher the overall fidelity improvement effect will be when calibrating the qubit gate based on the data group. Therefore, the qubit gate with the highest first fidelity gain can be used as the target qubit gate of the data group to generate the first mapping relationship between the data group and the target qubit gate.

[0158] The process of generating the first mapping relationship table from step 910 to step 930 is to determine the target qubit gate of each data group based on the calibration effect of the overall multiple qubit gates, and generate a first mapping relationship between the data group and the target qubit gate. This ensures that after the second qubit gate is obtained based on the first mapping relationship table, the calibration process of the fidelity of the second qubit gate is beneficial to the fidelity of the overall multiple qubit gates. Therefore, the first mapping relationship table generated in this embodiment can improve the calibration efficiency of the fidelity calibration of multiple qubit gates.

[0159] After determining the first fidelity interval in which the first fidelity is located, it is also necessary to determine the first calibration means for calibrating the second qubit gate according to the second mapping relationship between the first fidelity interval of the first qubit gate and the calibration means. The second mapping relationship may also be determined in advance so that the first calibration means can be determined directly according to the mapping relationship.

[0160] In the second mapping relationship, the calibration means corresponding to the first fidelity interval of the first quantum bit gate can be one or more. If there is one, then the calibration means is directly used as the first calibration means. If there are multiple, such as Fig.11 As shown, step 730 includes:

[0161] Step 1110: Obtain a second mapping relationship table;

[0162] Step 1120: Based on the first quantum bit gate and the first fidelity interval, search in the second mapping relationship table to obtain a plurality of first candidate calibration means;

[0163] Step 1130: Determine a first calibration means from a plurality of first candidate calibration means.

[0164] The second mapping relationship table indicates a second mapping relationship between the fidelity interval and the calibration method. Table 2 shows an example of the second mapping relationship table.

[0165] Quantum bit gates and fidelity intervals First candidate calibration method Door X [80%, 85%) A, E, M Door Y[80%,85%) B, D, H Door H [80%, 85%) C.N Gate I [80%, 85%) A, F, K Door X [85%, 90%) D, L, R Door Y[85%,90%) C, K, P …… …… Gate H [95%, 100%) E, G, K, M Gate I [95%, 100%) F.U

[0166] Table 2

[0167] Based on the second mapping relationship table in Table 2, when the first quantum bit gate is gate X and the first fidelity interval is [80%, 85%), the first candidate calibration means include A, E and M.

[0168] The generation process of the second mapping relationship table is based on the combination of quantum bit gates and fidelity intervals, determining the calibration method that can bring the best effect for multiple quantum bit gates, and generating the second mapping relationship.

[0169] Since the calibration method is to calibrate the fidelity of the quantum bit gate by adjusting the radio frequency signal of the quantum bit, the calibration method can be a combination of adjustment methods of different properties of the radio frequency signal.

[0170] In one embodiment, the method for calibrating the fidelity of a quantum bit gate further includes: generating multiple calibration means based on a combination of multiple amplitude values, multiple frequency values, and multiple phase values.

[0171] Among them, in the embodiment of the present disclosure, since the qubit gate is a logical operation based on the qubit, the fidelity of the multiple qubit gates corresponding to the qubit is the property of the qubit itself. In the embodiment of the present disclosure, the qubit can be specifically a radio frequency signal, and the radio frequency signal has three main parameters, namely, amplitude value, frequency value and phase value. The fidelity of the qubit gate is calibrated, and its essence is to adjust the properties of the qubit itself so that the fidelity of the qubit gate is increased; and the properties of the qubit itself in the embodiment of the present disclosure are adjusted, that is, any one or more of the amplitude value, frequency value or phase value of the radio frequency signal corresponding to the qubit is adjusted. Therefore, in the embodiment of the present disclosure, the specific operation of the calibration means for calibrating the fidelity of the qubit gate is to adjust any one or more of the amplitude value, frequency value or phase value of the radio frequency signal corresponding to the qubit. For different calibration means, the specific values ​​of the adjustment of the above three parameter values ​​are also different. For example, the first calibration means is to increase the frequency of the radio frequency signal corresponding to the qubit by x Hz; or for example, the second calibration means is to adjust the phase of the radio frequency signal by 20 degrees, etc. Based on different values ​​and combinations of the above three parameters, multiple calibration methods can be generated. The calibration goal of each calibration method is to approach the fidelity of the corresponding quantum bit gate to 100%.

[0172] In one embodiment, the process of generating the second mapping table may be performed after steps 910 to 930. Fig.12 As shown, after step 930, the following steps are included:

[0173] Step 1210, obtaining a second fidelity gain corresponding to each data group and multiple calibration means;

[0174] Step 1220: Determine a candidate calibration means corresponding to each data group according to the second fidelity gain, and generate a second mapping relationship table according to the mapping relationship between the data group and the candidate calibration means.

[0175] For each data group, the second fidelity gain is the fidelity difference before and after the corresponding qubit gate is calibrated using each calibration means, and the corresponding qubit gate is the target qubit gate that has a mapping relationship with each data group in the first mapping relationship table. For example, the calibration means include: calibration means A, calibration means B, calibration means C, and calibration means D. When determining the candidate calibration means for the data group (gate X, [85%, 90%)), based on the first mapping relationship table, the qubit gate to be calibrated corresponding to the data group is gate Y, and gate Y is calibrated using calibration means A, calibration means B, calibration means C, and calibration means D, respectively. If the fidelity of door Y before calibration is 80%, and after calibration by calibration means A, the fidelity is 85%, then the second fidelity gain corresponding to calibration means A is 5%; after calibration by calibration means B, the fidelity is 87%, then the second fidelity gain corresponding to calibration means B is 7%; after calibration by calibration means C, the fidelity is 77%, then the second fidelity gain corresponding to calibration means C is -3%; after calibration by calibration means D, the fidelity is 92%, then the second fidelity gain corresponding to calibration means D is 12%.

[0176] After determining the second fidelity gains corresponding to a plurality of calibration means for a data group, a candidate calibration means for the data group is determined according to the second fidelity gain.

[0177] In one embodiment, a candidate calibration means can be determined from multiple calibration means by setting a gain threshold. If the second fidelity gain of the calibration means is greater than or equal to the gain threshold, the calibration means is used as a candidate calibration means. For example, the gain threshold is 5%. Then, according to the second fidelity gains corresponding to calibration means A, calibration means B, calibration means C and calibration means D in the above example, calibration means A, calibration means B and calibration means D can be used as candidate calibration means for the data group (gate X, [85%, 90%)). The advantage of using the gain threshold to determine the candidate calibration means is that it can ensure that each candidate calibration means can bring a better calibration effect to the quantum bit gate to be calibrated corresponding to the data group.

[0178] In another embodiment, the candidate calibration means can be determined from a plurality of calibration means by setting the number of candidate calibration means, sorting the plurality of candidate calibration means according to the second fidelity gain, and using the number of candidate calibration means that are ranked in front as candidate calibration means. For example, if the number of candidate calibration means is 2, then according to the second fidelity gains corresponding to calibration means A, calibration means B, calibration means C, and calibration means D in the above example, calibration means B and calibration means D can be used as candidate calibration means for the data group (gate X, [85%, 90%)). Through this embodiment, if there are many calibration means whose corresponding second fidelity gains exceed the gain threshold, a few with higher second fidelity gains can be selected from them to determine the first calibration means, which helps to improve the efficiency of determining the first calibration means.

[0179] When generating the second mapping relationship between the data group and the candidate calibration means, the data group and the candidate calibration means may be directly generated in correspondence, such as the generation result shown in Table 3.

[0180] Quantum bit gates and fidelity intervals First candidate calibration method Door X [85%, 90%) B.D

[0181] Table 3

[0182] In some embodiments, the calibration weight of each candidate calibration means can also be determined according to the second fidelity gain of the candidate calibration means, and a second mapping relationship is generated by corresponding the data group to the calibration weight of the candidate calibration means. The calibration weight indicates the calibration amplitude of the candidate calibration means for the quantum bit gate to be calibrated corresponding to the data group. Here, the calibration amplitude can be specifically understood as the fidelity gain obtained by calibration. The larger the calibration amplitude, the larger the calibration weight value. For example, the second fidelity gain of calibration means B is 7%, and the second fidelity gain of calibration means D is 12%. Then the calibration weight of calibration means B is 7% / (7%+12%)=0.37, and the calibration weight of calibration means D is 12% / (7%+12%)=0.63. At this time, the second mapping relationship between the candidate calibration means and the candidate calibration means is generated as shown in Table 4.

[0183] Quantum bit gates and fidelity intervals First candidate calibration method Door X [85%, 90%) B(0.37), D(0.67)

[0184] Table 4

[0185] The advantage of recording the calibration weight in the second mapping relationship is that when determining the first calibration means, it can be determined directly according to the weight, thereby improving the efficiency of determining the first calibration means.

[0186] The advantage of the embodiment of steps 1210-1220 is that the second mapping relationship table is generated based on the data in the embodiment of steps 910-930, which improves the data for generating the second mapping relationship table, and the candidate calibration means is directly determined based on the target quantum bit gate that has a mapping relationship with each data group, thereby improving the accuracy of the determined candidate calibration means.

[0187] In step 1120, after obtaining the first mapping relationship table, multiple first candidate calibration means are searched in the second mapping relationship table based on the first quantum bit gate and the first fidelity interval.

[0188] Taking the second mapping relationship table in Table 2 as an example, if the first quantum bit gate is gate H and the first fidelity interval is [80%, 85%), then the multiple first candidate calibration means are calibration means C and calibration means N.

[0189] The calibration means are generated according to different dimensions of the RF signal, such as amplitude, frequency, phase, etc. For each dimension, the dimension value can be any value, and the calibration means cannot include all possible calibration means. Therefore, after obtaining the first candidate calibration means, other calibration means can be generated based on multiple first candidate calibration means to increase the number of candidate calibration means.

[0190] In one embodiment, the calibration means calibrates the fidelity of the qubit gate by adjusting one or more of the amplitude, frequency and phase of the radio frequency signal of the target qubit; Fig.13 As shown, after step 1120, the following further includes:

[0191] Step 1121, calculating the average values ​​of amplitudes corresponding to the plurality of first candidate calibration means to obtain a first amplitude average value, calculating the average values ​​of frequencies corresponding to the plurality of first candidate calibration means to obtain a first frequency average value, and calculating the average values ​​of phases corresponding to the plurality of first candidate calibration means to obtain a first phase average value;

[0192] Step 1122, determining a second candidate calibration means according to the first amplitude mean, the first frequency mean, and the first phase mean;

[0193] Step 1135: Determine a first calibration means from among multiple first candidate calibration means and second candidate calibration means.

[0194] In this embodiment, the calibration means is a combination of one or more of amplitude, frequency and phase. If there is only one, such as frequency, then this calibration means only adjusts the frequency of the radio frequency signal of the quantum bit. If there are multiple ones, then the parameters of multiple dimensions of the radio frequency signal of the quantum bit are adjusted.

[0195] Since the first candidate calibration means can produce a good calibration effect on the second quantum bit gate, the second candidate calibration means generated according to the multiple dimensional values ​​of the first candidate calibration means may also produce a good calibration effect on the second quantum bit gate. The amplitudes of the multiple first candidate calibration means are averaged to obtain a first amplitude mean, the frequencies are averaged to obtain a first frequency mean, and the phases are averaged to obtain a first phase mean. For example, the second candidate calibration means is generated according to the multiple first candidate calibration means.

[0196] As shown in Table 5.

[0197] Amplitude frequency Phase Calibration method A Increase 4dB Reduce 3MHZ Decrease by 8 degrees Calibration method B Increase 2dB —— Reduce by 7 degrees Calibration means C —— Reduce 3MHZ —— Calibration means D —— Lower 6MHZ Reduce by 9 degrees Second Candidate Calibration Method Increase 3dB Lower 4MHZ Decrease by 8 degrees

[0198] Table 5

[0199] According to calibration means A to calibration means D in Table 5, the amplitude, frequency and phase are averaged in turn, and the second candidate calibration means is obtained as follows: the amplitude is increased by 3dB, the frequency is reduced by 4MHZ, and the phase is reduced by 8 degrees.

[0200] Then, the first calibration means may be determined from a calibration means set consisting of the first candidate calibration means and the second candidate calibration means.

[0201] In the aforementioned embodiment, each first candidate calibration means in the second mapping relationship table includes a calibration weight. Therefore, the second candidate calibration means is determined according to the amplitude, frequency and phase of the plurality of first candidate calibration means, and the weighted average of the amplitudes of the plurality of first candidate calibration means can be calculated to obtain a second amplitude mean, the weighted average of the frequencies of the plurality of first candidate calibration means can be calculated to obtain a second frequency mean, the weighted average of the phases of the plurality of first candidate calibration means can be calculated to obtain a second phase mean, and the second candidate calibration means can be determined according to the second amplitude mean, the second frequency mean and the second phase mean.

[0202] Since a higher calibration weight represents a greater improvement in the fidelity of the second qubit gate by the first candidate calibration means, when generating the second candidate calibration means, the dimension value may be shifted toward the first candidate calibration means with a higher weight. For example, based on the calibration weight, the second candidate calibration means is generated according to multiple first candidate calibration means as shown in Table 6.

[0203] Amplitude frequency Phase Calibration means A(0.3) Increase 4dB Reduce 3MHZ Decrease by 8 degrees Calibration means B (0.4) Increase 2dB —— Reduce by 7 degrees Calibration means C(0.2) —— Reduce 3MHZ —— Calibration means D(0.1) —— Lower 6MHZ Reduce by 9 degrees Second Candidate Calibration Method Increase 2.86dB Reduce 3.5MHZ Decrease 7.625 degrees

[0204] Table 6

[0205] According to calibration means A to calibration means D in Table 6, based on the calibration weights of each first candidate calibration means, the weighted average values ​​of amplitude, frequency and phase are calculated in turn, and the second calibration means is obtained as follows: the amplitude is increased by 2.86dB, the frequency is reduced by 3.5MHZ, and the phase is reduced by 7.625 degrees.

[0206] The advantage of using weighted average to generate the second candidate calibration means is that the second candidate calibration means can be made closer to the first candidate calibration means which can bring better calibration effect for the second quantum bit gate fidelity, which is beneficial to improving the calibration effect of the second candidate calibration means on the second quantum bit gate fidelity.

[0207] In this embodiment, a second candidate calibration means is generated based on multiple first candidate calibration means. Compared with multiple first candidate calibration means, the second candidate calibration means may bring better calibration results, improve the ability to explore better calibration means, and thus improve the calibration efficiency of multiple quantum bit gate fidelity.

[0208] In step 1130, a first calibration means is determined from a plurality of first candidate calibration means. Based on one of the aforementioned embodiments, the second mapping table records the calibration weight of each first candidate calibration means. Therefore, the first calibration means can be determined directly from a plurality of first candidate calibration means according to the calibration weight.

[0209] In another embodiment, Fig.14 As shown, step 1130 includes:

[0210] Step 1410, obtaining a second fidelity corresponding to each first candidate calibration means;

[0211] Step 1420: Determine a first calibration means from among a plurality of first candidate calibration means based on the second fidelity corresponding to each first candidate calibration means.

[0212] In this embodiment, each first candidate calibration means is applied to the target qubit, and the target qubit is gated using the second qubit gate, and the second fidelity corresponding to the first candidate calibration means is determined according to the actual result and the expected result obtained. Based on the second fidelity corresponding to each first candidate calibration means, the first candidate calibration means with the largest second fidelity is used as the first calibration means.

[0213] In this embodiment, each first candidate calibration means is used to calibrate the second qubit gate of the target qubit, and the one with the best calibration effect is used as the first calibration means, thereby improving the accuracy of determining the first calibration means.

[0214] Since calibrating a qubit gate may affect the fidelity of other qubit gates, based on the embodiment of step 1410-step 1420, in one embodiment, Fig.15 As shown, after step 1410, the following steps are included:

[0215] Step 1415: Obtain a third fidelity corresponding to the first qubit gate after calibrating the second qubit gate based on each first candidate calibration means;

[0216] Step 1425: Determine a first calibration means from among a plurality of first candidate calibration means based on the second fidelity and the third fidelity corresponding to each first candidate calibration means.

[0217] In this embodiment, after calibrating the second qubit gate using each first candidate calibration means, the first qubit gate can be used to perform gate operation on the target qubit gate, and the third fidelity of the first qubit gate can be determined based on the gate operation result and the expected result. Then, based on the second fidelity and point fidelity corresponding to each first candidate calibration means, the first calibration means is determined from multiple first candidate calibration means. That is, in the disclosed embodiment, after determining the second fidelity corresponding to each calibration means (indicating the calibration effect of the calibration means on the second qubit gate), the third fidelity corresponding to each calibration means can be further determined (indicating the effect of the calibration means on the fidelity of the first qubit gate when calibrating the second qubit gate), and then the optimal candidate calibration means can be further comprehensively evaluated based on the second fidelity and the third fidelity as the first calibration means.

[0218] In one embodiment, Fig.16 As shown, step 1425 includes:

[0219] Step 1610: Determine a third fidelity gain corresponding to each first candidate calibration means based on the fidelity of the second qubit gate before calibration and the second fidelity corresponding to each first candidate calibration means;

[0220] Step 1620: Determine a fourth fidelity gain corresponding to each first candidate calibration means based on the first fidelity of the first qubit gate and the third fidelity corresponding to each first candidate calibration means;

[0221] Step 1630: Determine the first calibration means based on the third fidelity gain and the fourth fidelity gain corresponding to each first candidate calibration means.

[0222] In this embodiment, for each first candidate calibration means, the difference in fidelity before and after calibration of the second qubit gate is obtained as the third fidelity gain, and the difference in fidelity of the first qubit gate before and after calibration of the second qubit gate is obtained as the fourth fidelity gain. For example, before calibration of the second qubit gate, the fidelity of the second qubit gate is 80%, and the first fidelity of the first qubit gate is 83%. After calibration of the second qubit gate by a first candidate calibration means, the second fidelity of the second qubit gate is 92%, and the third fidelity of the first qubit gate is 80%. Then, the third fidelity gain corresponding to the first candidate calibration means is 92%-80%=12%, and the fourth fidelity gain is 80%-83%=-3%.

[0223] Based on the third fidelity gain and the fourth fidelity gain corresponding to each first candidate calibration means, the first calibration means can be determined by directly adding the third fidelity gain and the fourth fidelity gain, and the first candidate calibration means with the largest sum result is used as the first calibration means. For example, the third fidelity gain of calibration means A is 12%, and the fourth fidelity gain is -3%; the third fidelity gain of calibration means B is 8%, and the fourth fidelity gain is 3%; the third fidelity gain of calibration means C is 7%, and the fourth fidelity gain is 1%. The third fidelity gain and the fourth fidelity gain of the three calibration means are added to obtain 9%, 11% and 8% respectively, and the calibration means B corresponding to 11% is used as the first calibration means. By directly adding, the third fidelity gain and the fourth fidelity gain have the same influence on the determination of the first calibration means, which improves the fairness of determining the first calibration means.

[0224] Based on the third fidelity gain and the fourth fidelity gain corresponding to each first candidate calibration means, the first calibration means is determined. Different weights can also be set for the third fidelity gain and the fourth fidelity gain, and a weighted sum is performed based on the weights, and the first candidate calibration means with the largest weighted sum result is used as the first calibration means. The purpose of setting the weight is that since the first candidate calibration means acts on the second qubit gate, the fidelity of the first qubit gate will continue to be calibrated later, and the fidelity change of the second qubit gate is more important for determining the first calibration means. Therefore, the weight is used to represent the bias towards the fidelity change of the first qubit gate and the second qubit gate. For example, the weight of the third fidelity gain is 0.7, and the weight of the fourth fidelity gain is 0.3. Based on the above example, the result of the weighted sum for calibration means A is 7.5%, the result of the weighted sum for calibration means B is 6.5%, and the result of the weighted sum for calibration means C is 5.2%. Therefore, calibration means A is used as the first calibration means. By using a weighted sum method, different weights can be set for the third fidelity gain and the fourth fidelity gain according to actual application requirements, thereby improving the flexibility of determining the first calibration means.

[0225] In the embodiment of steps 1610 to 1630, the overall impact of each first candidate calibration means on the fidelity of the first quantum bit gate and the second quantum bit gate after calibrating the second quantum bit gate is comprehensively considered, and the first candidate calibration means that is most beneficial to the overall situation is used as the first calibration means, thereby improving the accuracy of determining the first calibration means.

[0226] In another embodiment, determining the first calibration means based on the second fidelity and the third fidelity corresponding to the first candidate calibration means includes:

[0227] sorting the first candidate calibration means based on the order of the second fidelity from high to low;

[0228] Starting with the first candidate calibration in the ranking, the loop performs the following steps:

[0229] comparing the first fidelity with a third fidelity corresponding to the first candidate calibration means;

[0230] If the third fidelity is greater than or equal to the first fidelity, the loop is terminated and the corresponding first candidate calibration means is used as the first calibration means.

[0231] The specific process of this embodiment is as follows Fig.17As shown, x represents the calibration means, and the first candidate calibration means are sorted in descending order according to the second fidelity, and the obtained [x1, x2, x3, ...] are obtained; k represents the first candidate calibration means of the current loop step, and the judgment is started from the first candidate calibration means in the sorting (corresponding to the highest second fidelity); F1 represents the first fidelity of the first quantum bit gate, and k.F3 represents the third fidelity corresponding to the first candidate calibration means represented by k. If the first fidelity is greater than the third fidelity, it means that after the second quantum bit gate is calibrated by the first candidate calibration means represented by k, the fidelity of the first quantum bit gate is reduced. Even if this first candidate calibration means can bring a better calibration effect for the fidelity of the second quantum bit gate, it is not the best choice. Therefore, the loop step is continued for the next first candidate calibration means in the sorting; if the first fidelity is less than or equal to the third fidelity, it means that after the second quantum bit gate is calibrated by the first candidate calibration means represented by k, there will be no negative impact on the fidelity of the first quantum bit gate. Therefore, this first candidate calibration means can be used as the first calibration means.

[0232] For example, the first fidelity of the first qubit gate is 80%, the second fidelity corresponding to calibration method A is 90%, and the third fidelity is 78%; the second fidelity corresponding to calibration method B is 86%, and the third fidelity is 81%; the second fidelity corresponding to calibration method C is 84%, and the third fidelity is 83%. After sorting by the second fidelity, the order obtained is calibration method A, calibration method B, and calibration method C. For calibration method A, the third fidelity is less than the first fidelity, so continue to query calibration method B. For calibration method B, the third fidelity is greater than the first fidelity, so calibration method B is used as the first calibration method.

[0233] The advantage of this embodiment is that, under the premise of comprehensively considering the fidelity changes of the first quantum bit gate and the second quantum bit gate, there is no need to calculate the impact of each calibration means on the fidelity of the first quantum bit gate and the second quantum bit gate, thereby reducing the amount of calculation and improving the efficiency of determining the first calibration means.

[0234] Fig.15 The advantage of the embodiment is that, when determining the first calibration means, not only the impact of the first candidate calibration means on the second quantum bit gate is considered, but also the impact on the first quantum bit gate is considered, thereby avoiding the problem that the fidelity of one quantum bit gate is improved while the fidelity of another quantum bit gate is reduced, ensuring the overall fidelity calibration effect of multiple quantum bit gates, and improving the efficiency of the overall fidelity calibration.

[0235] The advantage of the embodiment of step 1110-step 1130 is that, by utilizing the second mapping relationship table, the efficiency of searching for multiple first candidate calibration means is improved, the first calibration means is determined from multiple first candidate calibration means, and it is ensured that the first calibration means can bring the best calibration effect for the second quantum bit gate, thereby improving the calibration efficiency of determining the fidelity.

[0236] In the embodiment of step 710-step 730, the second quantum bit gate is determined based on the first mapping relationship, and the first calibration means is determined based on the second mapping relationship. There is no need to traverse multiple quantum bit gates and a large number of calibration means, thereby improving the efficiency of determining the second quantum bit gate and the first calibration means.

[0237] Detailed description of step 340

[0238] In step 340, the second qubit gate is calibrated using the first calibration means, which essentially uses the first calibration means to adjust the radio frequency signal of the target qubit so that gate operation based on the second qubit gate on the target qubit can make the state of the target qubit as close to the desired state as possible.

[0239] The embodiment of step 310-step 340 only describes in detail the process of calibrating one of the multiple qubit gates of the target qubit. In fact, multiple qubit gates can be calibrated. Therefore, the embodiment of step 310-step 340 can be used as the starting process for calibrating multiple qubit gates. In one embodiment, Fig.18 As shown, after step 340, the following further includes:

[0240] Step 1810: Determine the second qubit gate as the current qubit gate, and loop through the following steps:

[0241] Step 1820: Perform fidelity detection on multiple quantum bit gates;

[0242] Step 1830: when it is detected that the fidelity of a qubit gate among the multiple qubit gates is less than a predetermined fidelity value, determine the qubit gate to be calibrated and the calibration means for calibrating the qubit gate to be calibrated according to the fidelity of the current qubit gate, calibrate the qubit gate to be calibrated based on the calibration means, and update the current qubit gate based on the qubit gate to be calibrated;

[0243] Step 1840: When the fidelity of multiple quantum bit gates is greater than or equal to a predetermined fidelity value, terminate the loop step.

[0244] In this embodiment, after the second qubit gate is calibrated, the second qubit gate is used as the current qubit gate and a loop step is entered: a fidelity test is performed on multiple qubit gates; if there is a qubit gate among the multiple qubit gates whose fidelity is less than a predetermined fidelity value, then the qubit gate to be calibrated and the calibration means for calibrating the qubit gate to be calibrated are determined according to the fidelity of the current qubit gate. The specific process is the same as determining the second qubit gate and the first calibration means according to the first fidelity in step 330, and will not be repeated here; the qubit gate to be calibrated is calibrated based on the calibration means, and the qubit gate to be calibrated is used as the current qubit gate, and the loop step is re-executed; if the fidelity of multiple qubit gates is greater than the predetermined fidelity value, it means that multiple qubit gates have met the calibration requirements, and the loop step is terminated.

[0245] The predetermined fidelity value is the threshold at which the fidelity of the quantum bit gate reaches the calibration requirement. When the fidelity of the quantum bit gate is greater than or equal to the predetermined fidelity value, the target quantum bit can be used to perform quantum computing tasks.

[0246] Refer to the following Fig.19 The process of calibrating multiple qubit gates of a target qubit is exemplified.

[0247] For example, the quantum bit gates corresponding to the target quantum bit include: Gate I, Gate X, Gate Y and Gate M, with initial fidelities of 75%, 77%, 81% and 78% respectively.

[0248] In step 1910, the initial quantum bit gate with the highest fidelity is used as the first quantum bit gate, so the first quantum bit gate is gate Y.

[0249] In step 1911, a gate operation of gate Y is performed on the target quantum bit, and the first fidelity of the first quantum bit gate is determined to be 81% based on the difference between the actual result of the operation and the expected result.

[0250] In step 1912, it is determined that the first fidelity interval in which the first fidelity is located is [80%, 85%).

[0251] In step 1913, a first mapping relationship table is obtained, and according to the first quantum bit gate and the first fidelity interval, the second quantum bit gate to be calibrated is searched in the first mapping relationship table as gate X.

[0252] In step 1914, a second mapping relationship table is obtained, and according to the first quantum bit gate and the first fidelity interval, a plurality of first candidate calibration means are found in the second mapping relationship table, namely, calibration means D, calibration means F and calibration means G.

[0253] In step 1915, the second fidelity corresponding to each first candidate calibration means is obtained, the second fidelity corresponding to calibration means D is 86%, the second fidelity corresponding to calibration means F is 97%, and the second fidelity corresponding to calibration means G is 95%.

[0254] In step 1916, after calibrating the second quantum bit gate based on each first candidate calibration means, the third fidelity corresponding to the first quantum bit gate is: the third fidelity corresponding to calibration means D is 81%, the third fidelity corresponding to calibration means F is 80%; the third fidelity corresponding to calibration means G is 82%.

[0255] In step 1917, based on the second fidelity and the third fidelity corresponding to each first candidate calibration means, a first calibration means is determined from a plurality of first candidate calibration means, and the first calibration means is calibration means G;

[0256] In step 1918, the gate X is calibrated using calibration means G.

[0257] In step 1919, gate X is determined to be the current qubit gate.

[0258] Enter step 1920 for the first time and perform fidelity detection on all quantum bit gates. The fidelities of gate I, gate X, gate Y and gate M are 75%, 95%, 81% and 78% respectively. The predetermined fidelity value is 95%. If there is a quantum bit gate with a fidelity less than the predetermined fidelity value, enter step 1921.

[0259] In step 1921, the qubit gate to be calibrated is determined to be gate I based on the fidelity of gate X (95%), the calibration means applied is calibration means C, gate I is calibrated using calibration means C, gate I is used as the current qubit gate, and step 1920 is entered.

[0260] Enter step 1920 for the second time and perform fidelity detection on all quantum bit gates. The fidelity of gate I, gate X, gate Y and gate M are 96%, 95%, 81% and 78% respectively. If there is a quantum bit gate with a fidelity less than the predetermined fidelity value, enter step 1921.

[0261] In step 1921, the quantum bit gate to be calibrated is determined to be gate M based on the fidelity of gate I (96%), the calibration means applied is calibration means K, gate M is calibrated using calibration means K, gate M is used as the current quantum bit gate, and step 1920 is entered.

[0262] Enter step 1920 for the third time and perform fidelity detection on all quantum bit gates. The fidelities of gate I, gate X, gate Y and gate M are 96%, 95%, 81% and 95% respectively. If there is a quantum bit gate with a fidelity less than the predetermined fidelity value, enter step 1921.

[0263] In step 1921, the quantum bit gate to be calibrated is determined to be gate Y based on the fidelity (95%) of gate M, the calibration means applied is calibration means S, gate Y is calibrated using calibration means S, and gate Y is used as the current quantum bit gate, and step 1920 is entered.

[0264] Enter step 1920 for the fourth time and perform fidelity detection on all quantum bit gates. The fidelity of gate I, gate X, gate Y and gate M are 96%, 95%, 97% and 95% respectively. There is no quantum bit gate with a fidelity less than the predetermined fidelity value, so enter step 1922.

[0265] In step 1922, the loop step is terminated to complete the calibration of multiple quantum bit gates of the target quantum bit.

[0266] Description of the apparatus and device of the present disclosure

[0267] In each specific implementation of the present application, when it comes to the need to perform relevant processing based on data related to the characteristics of the object such as object attribute information or attribute information sets, the permission or consent of the object will be obtained first, and the collection, use and processing of these data will comply with the relevant laws, regulations and standards of the relevant countries and regions. In addition, when the embodiment of the present application needs to obtain object attribute information, the object's separate permission or separate consent will be obtained through a pop-up window or jump to a confirmation page. After clearly obtaining the object's separate permission or separate consent, the necessary object-related data for the normal operation of the embodiment of the present application will be obtained.

[0268] Reference Fig. 20 , Fig. 20 A schematic diagram of the structure of a qubit gate fidelity calibration device 2000 provided in an embodiment of the present disclosure, wherein the qubit gate fidelity calibration device 2000 comprises:

[0269] A first determining unit 2010, configured to determine a first qubit gate among a plurality of qubit gates of a target qubit;

[0270] A first acquisition unit 2020, configured to acquire a first fidelity of a first quantum bit gate;

[0271] A second determining unit 2030 is used to determine a second qubit gate to be calibrated according to the first fidelity, and determine a first calibration means for calibrating the second qubit gate;

[0272] The calibration unit 2040 is used to calibrate the second quantum bit gate based on the first calibration method.

[0273] Optionally, the second determining unit 2030 is specifically configured to:

[0274] Determining a first fidelity interval in which the first fidelity is located;

[0275] Determining a second qubit gate to be calibrated according to a first mapping relationship between the first fidelity interval and the qubit gate to be calibrated;

[0276] According to a second mapping relationship between the first fidelity interval and the calibration means, a first calibration means for calibrating the second quantum bit gate is determined.

[0277] Optionally, the second determining unit 2030 is specifically configured to:

[0278] Obtaining a first mapping relationship table, the first mapping relationship table indicating a first mapping relationship between a fidelity interval and a quantum bit gate to be calibrated;

[0279] According to the first quantum bit gate and the first fidelity interval, a second quantum bit gate to be calibrated is obtained by searching in the first mapping relationship table.

[0280] Optionally, the second determining unit 2030 is specifically configured to:

[0281] Acquire a second mapping relationship table, where the second mapping relationship table indicates a second mapping relationship between the fidelity interval and the calibration means;

[0282] Based on the first quantum bit gate and the first fidelity interval, searching in the second mapping relationship table to obtain a plurality of first candidate calibration means;

[0283] A first calibration means is determined from a plurality of first candidate calibration means.

[0284] Optionally, the second determining unit 2030 is specifically configured to:

[0285] Obtaining a second fidelity corresponding to each first candidate calibration means, where the second fidelity is a fidelity obtained by calibrating the second quantum bit gate based on each first candidate calibration means;

[0286] A first calibration means is determined from a plurality of first candidate calibration means based on the second fidelity corresponding to each first candidate calibration means.

[0287] Optionally, the second determining unit 2030 is specifically configured to:

[0288] Obtaining a third fidelity corresponding to the first qubit gate after calibrating the second qubit gate based on each first candidate calibration means;

[0289] A first calibration means is determined from a plurality of first candidate calibration means based on the second fidelity and the third fidelity corresponding to each first candidate calibration means.

[0290] Optionally, the calibration means calibrates the fidelity of the qubit gate by adjusting one or more of the amplitude, frequency and phase of the radio frequency signal of the target qubit;

[0291] The second determining unit 2030 is specifically configured to:

[0292] Calculating the average of the amplitudes corresponding to the plurality of first candidate calibration means to obtain a first amplitude average, calculating the average of the frequencies corresponding to the plurality of first candidate calibration means to obtain a first frequency average, and calculating the average of the phases corresponding to the plurality of first candidate calibration means to obtain a first phase average;

[0293] Determine a second candidate calibration means according to the first amplitude mean, the first frequency mean, and the first phase mean;

[0294] A first calibration means is determined from a calibration means set consisting of a plurality of first candidate calibration means and a second candidate calibration means.

[0295] Optionally, the first mapping relationship table is generated in the following manner:

[0296] Generate multiple data groups based on multiple quantum bit gates and multiple fidelity intervals, where the data groups are generated by combining any quantum bit gate with any fidelity interval;

[0297] Obtaining a first fidelity gain corresponding to each data group and the plurality of qubit gates, the first fidelity gain being a difference between the sum of the fidelities of the plurality of qubit gates before and after calibration of the corresponding qubit gates;

[0298] The target quantum bit gate corresponding to each data group is determined according to the first fidelity gain, and a first mapping relationship table is generated according to the mapping relationship between the data group and the target quantum bit gate.

[0299] Optionally, the method further comprises:

[0300] generating a plurality of calibration means based on a combination of a plurality of amplitude values, a plurality of frequency values, and a plurality of phase values;

[0301] After determining the target quantum bit gate corresponding to each data group according to the first fidelity gain, and generating a first mapping relationship table according to the mapping relationship between the data group and the target quantum bit gate, the method further includes:

[0302] Obtaining a second fidelity gain corresponding to each data group and a plurality of calibration means, the second fidelity gain being a fidelity difference before and after calibrating a corresponding qubit gate using each calibration means, the corresponding qubit gate being a target qubit gate that has a mapping relationship with each data group in the first mapping relationship table;

[0303] A candidate calibration means corresponding to each data group is determined according to the second fidelity gain, and a second mapping relationship table is generated according to the mapping relationship between the data group and the candidate calibration means.

[0304] Optionally, the quanta gate fidelity calibration device 2000 further includes:

[0305] A cyclic calibration unit (not shown) is used to determine that the second qubit gate is the current qubit gate, and cyclically execute the following steps:

[0306] Fidelity testing of multiple qubit gates;

[0307] When it is detected that the fidelity of a qubit gate among the multiple qubit gates is less than a predetermined fidelity value, determining the qubit gate to be calibrated and the calibration means for calibrating the qubit gate to be calibrated according to the fidelity of the current qubit gate, calibrating the qubit gate to be calibrated based on the calibration means, and updating the current qubit gate based on the qubit gate to be calibrated;

[0308] When the fidelity of the multiple quantum bit gates is greater than or equal to the predetermined fidelity value, the loop step is terminated.

[0309] Optionally, the first acquiring unit 2020 includes:

[0310] Performing an operation corresponding to the first quantum bit gate on the target quantum bit and obtaining an actual state of the target quantum bit;

[0311] A first fidelity of the first qubit gate is determined based on a difference between the actual state and the expected state.

[0312] Optionally, the first determining unit 2010 includes:

[0313] Obtaining an initial fidelity value of each qubit gate in a plurality of qubit gates of a target qubit;

[0314] The quantum bit gate with the highest initial fidelity value is determined to be the first quantum bit gate.

[0315] Fig.21A block diagram of the structure of a portion of a computer 140 for implementing the method for calibrating the fidelity of a quantum bit gate according to an embodiment of the present disclosure. The computer 140 may have relatively large differences due to different configurations or performances, and may include one or more central processing units (CPUs) 2122 (e.g., one or more processors) and a memory 2132, and one or more storage media 2130 (e.g., one or more mass storage devices) storing application programs 2142 or data 2144. Among them, the memory 2132 and the storage medium 2130 may be short-term storage or permanent storage. The program stored in the storage medium 2130 may include one or more modules (not shown in the figure), and each module may include a series of instruction operations in the computer 140. Furthermore, the central processing unit 2122 may be configured to communicate with the storage medium 2130 to execute a series of instruction operations in the storage medium 2130 on the computer 140.

[0316] The computer 140 may also include one or more power supplies 2126, one or more wired or wireless network interfaces 2150, one or more input and output interfaces 2158, and / or one or more operating systems 2141, such as Windows Server™, Mac OS X™, Unix™, Linux™, FreeBSD™, etc.

[0317] The processor in the computer 140 may be used to execute the method for calibrating the fidelity of the quantum bit gate according to the embodiment of the present disclosure.

[0318] The embodiments of the present disclosure also provide a computer-readable storage medium, which is used to store program codes, and the program codes are used to execute the quantum bit gate fidelity calibration method of each of the aforementioned embodiments.

[0319] The embodiment of the present disclosure also provides a computer program product, which includes a computer program. A processor of a computer device reads and executes the computer program, so that the computer device executes the above-mentioned calibration method for the fidelity of a quantum bit gate.

[0320] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "comprises" and "comprising" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0321] It should be understood that in the present disclosure, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0322] It should be understood that in the description of the embodiments of the present disclosure, the meaning of multiple (or multiple items) is more than two, greater than, less than, exceed, etc. are understood to not include the number, and above, below, within, etc. are understood to include the number.

[0323] In the several embodiments provided in the present disclosure, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0324] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0325] In addition, each functional unit in each embodiment of the present disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0326] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present disclosure is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present disclosure. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), disk or optical disk and other media that can store program codes.

[0327] It should also be understood that the various implementations provided in the embodiments of the present disclosure can be combined arbitrarily to achieve different technical effects.

[0328] The above is a specific description of the implementation methods of the present disclosure, but the present disclosure is not limited to the above implementation methods. Technical personnel familiar with the art can also make various equivalent modifications or substitutions without violating the spirit of the present disclosure. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present disclosure.

Claims

1. A method for calibrating the fidelity of a quantum bit gate, characterized in that: include: Determining a first qubit gate among a plurality of qubit gates of a target qubit, wherein the plurality of qubit gates are a plurality of qubit gate operations performed based on the target qubit; Obtaining a first fidelity of the first quantum bit gate; Determining a second qubit gate to be calibrated and a first calibration means for calibrating the second qubit gate according to the first fidelity; The second quantum bit gate is calibrated based on the first calibration method.

2. The method according to claim 1, characterized in that: The determining, according to the fidelity of the first gate, a second qubit gate to be calibrated and a first calibration means for calibrating the second qubit gate comprises: Determining a first fidelity interval in which the first fidelity lies; Determining a second qubit gate to be calibrated according to a first mapping relationship between the first fidelity interval and the qubit gate to be calibrated; A first calibration means for calibrating the second quantum bit gate is determined according to a second mapping relationship between the first fidelity interval and the calibration means.

3. The method according to claim 2, characterized in that The determining, according to a first mapping relationship between the first fidelity interval and the qubit gate to be calibrated, a second qubit gate to be calibrated comprises: Obtaining a first mapping relationship table, wherein the first mapping relationship table indicates a first mapping relationship between a fidelity interval and a quantum bit gate to be calibrated; According to the first qubit gate and the first fidelity interval, a second qubit gate to be calibrated is obtained by searching in the first mapping relationship table.

4. The method according to claim 2, characterized in that: The determining, according to a second mapping relationship between the first fidelity interval and the calibration means, a first calibration means for calibrating the second quantum bit gate comprises: Acquire a second mapping relationship table, wherein the second mapping relationship table indicates a second mapping relationship between the fidelity interval and the calibration means; Based on the first quantum bit gate and the first fidelity interval, searching in the second mapping relationship table to obtain a plurality of first candidate calibration means; A first calibration approach is determined from the plurality of first candidate calibration approaches.

5. The method according to claim 4, characterized in that The determining of the first calibration means from the plurality of first candidate calibration means comprises: Obtaining a second fidelity corresponding to each first candidate calibration means, where the second fidelity is a fidelity obtained by calibrating the second quantum bit gate based on each first candidate calibration means; A first calibration method is determined from the plurality of first candidate calibration methods based on the second fidelity corresponding to each of the first candidate calibration methods.

6. The method according to claim 5, characterized in that The obtaining of the second fidelity corresponding to each first candidate calibration means, wherein the second fidelity is the fidelity obtained by calibrating the second qubit gate based on each first candidate calibration means, further includes: Obtaining a third fidelity corresponding to the first qubit gate after calibrating the second qubit gate based on each of the first candidate calibration means; The determining the first calibration means from the plurality of first candidate calibration means based on the second fidelity corresponding to each of the first candidate calibration means comprises: The first calibration means is determined from the plurality of first candidate calibration means based on the second fidelity and the third fidelity corresponding to each of the first candidate calibration means.

7. The method according to claim 4, characterized in that The calibration means calibrates the fidelity of the quantum bit gate by adjusting one or more of the amplitude, frequency and phase of the radio frequency signal of the target quantum bit; after searching and obtaining a plurality of first candidate calibration means in the second mapping relationship table based on the first quantum bit gate and the first fidelity interval, the method further includes: Calculating the average values ​​of the amplitudes corresponding to the plurality of first candidate calibration means to obtain a first amplitude average value, calculating the average values ​​of the frequencies corresponding to the plurality of first candidate calibration means to obtain a first frequency average value, and calculating the average values ​​of the phases corresponding to the plurality of first candidate calibration means to obtain a first phase average value; Determine a second candidate calibration means according to the first amplitude mean, the first frequency mean, and the first phase mean; The determining of the first calibration means from the plurality of first candidate calibration means comprises: A first calibration means is determined from a calibration means set consisting of the plurality of first candidate calibration means and the second candidate calibration means.

8. The method according to claim 3, characterized in that The first mapping relationship table is generated in the following manner: Generate multiple data groups based on multiple quantum bit gates and multiple fidelity intervals, wherein the data groups are generated by combining any quantum bit gate with any fidelity interval; Obtaining a first fidelity gain corresponding to each data group and the plurality of qubit gates, the first fidelity gain being a difference between the sum of the fidelities of the plurality of qubit gates before and after calibration of the corresponding qubit gate; A target quantum bit gate corresponding to each data group is determined according to the first fidelity gain, and a first mapping relationship table is generated according to a mapping relationship between the data group and the target quantum bit gate.

9. The method according to claim 8, characterized in that The method further comprises: generating a plurality of calibration means based on a combination of a plurality of amplitude values, a plurality of frequency values, and a plurality of phase values; After determining the target qubit gate corresponding to each data group according to the first fidelity gain, and generating a first mapping relationship table according to the mapping relationship between the data group and the target qubit gate, the method further includes: Obtaining a second fidelity gain corresponding to each data group and the multiple calibration means, the second fidelity gain being a fidelity difference before and after calibrating a corresponding qubit gate using each calibration means, the corresponding qubit gate being a target qubit gate that has a mapping relationship with each data group in the first mapping relationship table; A candidate calibration means corresponding to each data group is determined according to the second fidelity gain, and a second mapping relationship table is generated according to a mapping relationship between the data group and the candidate calibration means.

10. The method according to claim 1, characterized in that After calibrating the second quantum bit gate based on the first calibration means, the method further includes: Determine that the second qubit gate is the current qubit gate, and loop through the following steps: Performing fidelity testing on the plurality of quantum bit gates; When it is detected that the fidelity of a qubit gate among the multiple qubit gates is less than a predetermined fidelity value, determining a qubit gate to be calibrated and a calibration means for calibrating the qubit gate to be calibrated according to the fidelity of the current qubit gate, calibrating the qubit gate to be calibrated based on the calibration means, and updating the current qubit gate based on the qubit gate to be calibrated; When the fidelity of the plurality of quantum bit gates is greater than or equal to a predetermined fidelity value, the loop step is terminated.

11. The method according to claim 1, characterized in that: Obtaining a first fidelity of the first quantum bit gate includes: Performing an operation corresponding to the first quantum bit gate on the target quantum bit, and obtaining an actual state of the target quantum bit; The first fidelity of the first qubit gate is determined based on a difference between the actual state and a desired state.

12. The method according to claim 1, characterized in that The step of determining a first qubit gate among a plurality of qubit gates of a target qubit comprises: Obtaining an initial fidelity value of each qubit gate in a plurality of qubit gates of a target qubit; The quantum bit gate with the highest initial fidelity value is determined to be the first quantum bit gate.

13. A device for calibrating the fidelity of a quantum bit gate, characterized in that: include: A first determining unit, configured to determine a first qubit gate among a plurality of qubit gates of a target qubit; A first acquisition unit, configured to acquire a first fidelity of the first quantum bit gate; A second determining unit, configured to determine a second qubit gate to be calibrated according to the first fidelity, and determine a first calibration means for calibrating the second qubit gate; A calibration unit is used to calibrate the second quantum bit gate based on the first calibration means.

14. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method for calibrating the fidelity of the quantum bit gate described in any one of claims 1 to 12 is implemented.

15. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for calibrating the fidelity of a quantum bit gate as described in any one of claims 1 to 12 is implemented.

16. A computer program product, comprising a computer program, wherein the computer program is read and executed by a processor of a computer device, so that the computer device executes the method for calibrating the fidelity of a quantum bit gate as described in any one of claims 1 to 12.

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