CN114462614B

CN114462614B - Quantum noise intensity determination method and device, electronic equipment and medium

Info

Publication number: CN114462614B
Application number: CN202210134526.3A
Authority: CN
Inventors: 王琨; 唐双红
Original assignee: Beijing Baidu Netcom Science and Technology Co Ltd
Current assignee: Beijing Baidu Netcom Science and Technology Co Ltd
Filing date: 2022-02-14
Publication date: 2024-07-12
Anticipated expiration: 2042-02-14

Abstract

The present disclosure provides a quantum noise intensity determination method, apparatus, electronic device, computer readable storage medium and computer program product, relating to the field of quantum computers, in particular to the field of quantum noise sustained release technology. The implementation scheme is as follows: obtaining the maximum mixed state, and repeatedly operating the quantum measurement equipment to measure the first numerical number of times of the maximum mixed state; obtaining a maximum superposition state to repeatedly operate the quantum measurement device to measure a second number of times of the maximum superposition state; respectively counting the measurement results of the maximum mixed state and the maximum overlapped state to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of a corresponding measurement result of the maximum overlapped state; and determining a quantum noise intensity of the quantum measurement device based on a difference between the respective first probability value and the corresponding second probability value of the at least one measurement.

Description

Quantum noise intensity determination method and device, electronic equipment and medium

Technical Field

The present disclosure relates to the field of quantum computers, and in particular, to the field of quantum noise sustained release technology, and more particularly, to a method and apparatus for determining quantum noise intensity of a quantum measurement device, an electronic device, a computer readable storage medium, and a computer program product.

Background

Quantum computer technology has evolved rapidly in recent years, but noise problems in foreseeable future quantum computers are difficult to avoid: the heat dissipation in the qubit or random fluctuation generated in the underlying quantum physical process can cause the state of the qubit to be overturned or randomized, and the deviation of the calculation result read by the measuring device can cause the calculation process to fail.

Specifically, due to limitations of various factors such as instruments, methods, conditions and the like, the quantum measurement device cannot work accurately, so that measurement noise is generated, and deviation occurs in an actual measurement value. Therefore, it is often desirable to reduce the effects of measurement noise in order to obtain an unbiased estimate of the measurement.

Disclosure of Invention

The present disclosure provides a quantum noise intensity determination method, apparatus, electronic device, computer-readable storage medium, and computer program product for a quantum measurement device.

According to an aspect of the present disclosure, there is provided a quantum noise intensity determining method of a quantum measurement device, including: obtaining the maximum mixed state of n quantum bits, wherein n is the quantum bit number of the quantum measurement equipment; repeatedly operating the quantum measurement equipment to measure the maximum mixed state for a first number of times so as to obtain a measurement result; obtaining the maximum superposition state of n quantum bits; repeatedly operating the quantum measurement equipment to measure the maximum superposition state for a second number of times so as to obtain a measurement result; respectively counting the measurement results of the maximum mixed state and the maximum overlapped state to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of at least one measurement result corresponding to the maximum overlapped state; and determining a quantum noise intensity of the quantum measurement device based on a difference between the respective first probability value and the corresponding second probability value of the at least one measurement.

According to another aspect of the present disclosure, there is provided an error sustained release method of a quantum measurement apparatus, including: determining a quantum noise intensity of the quantum measurement device; and determining a corresponding method of a chromatography method of the quantum measurement equipment and a calibration method of the quantum measurement equipment based on the determined quantum noise intensity, and carrying out error slow release on the quantum measurement equipment. The quantum noise intensity of the quantum measuring device is determined based on the method described above.

According to another aspect of the present disclosure, there is provided a quantum noise intensity determining apparatus of a quantum measurement device, including: a first acquisition unit configured to acquire a maximum mixed state of n qubits, where n is a number of qubits of the quantum measurement device; a first measurement unit configured to repeatedly operate the quantum measurement device to measure the maximum mixed state for a first number of times to obtain a measurement result; the second acquisition unit is configured to acquire the maximum superposition state of the n quantum bits; a second measurement unit configured to repeatedly operate the quantum measurement device to perform measurement for a second number of times on the maximum superposition state to obtain a measurement result; the statistics unit is configured to respectively count the measurement results of the maximum mixed state and the maximum superposition state so as to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of at least one measurement result corresponding to the maximum superposition state; and a first determination unit configured to determine a quantum noise intensity of the quantum measurement device based on a difference between the respective first probability value and the corresponding second probability value of the at least one measurement result.

According to another aspect of the present disclosure, there is provided an error sustained release apparatus of a quantum measurement device, including: a second determination unit configured to determine a quantum noise intensity of the quantum measurement device; and a third determination unit configured to determine, based on the determined quantum noise intensity, that the quantum measurement device is erroneously delayed by a corresponding one of a quantum measurement device tomographic method and a quantum measurement device calibration method. The quantum noise intensity of the quantum measuring device is determined based on the method described above.

According to another aspect of the present disclosure, there is provided an electronic device including: at least one processor; and a memory communicatively coupled to the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the methods described in the present disclosure.

According to another aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method described in the present disclosure.

According to another aspect of the present disclosure, there is provided a computer program product comprising a computer program which, when executed by a processor, implements the method described in the present disclosure.

According to one or more embodiments of the present disclosure, the quantum noise intensity of the quantum measurement device may be efficiently determined, and further, whether more resources are required to be consumed to characterize the entire information of the quantum measurement device may be determined based on the determined quantum noise intensity, thereby improving the accuracy of the calculation result.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following specification.

Drawings

The accompanying drawings illustrate exemplary embodiments and, together with the description, serve to explain exemplary implementations of the embodiments. The illustrated embodiments are for exemplary purposes only and do not limit the scope of the claims. Throughout the drawings, identical reference numerals designate similar, but not necessarily identical, elements.

FIG. 1 illustrates a schematic diagram of an exemplary system in which various methods described herein may be implemented, in accordance with an embodiment of the present disclosure;

FIG. 2 shows a flow chart of error propagation by a quantum measurement device calibration method;

FIG. 3 illustrates a flow chart of a quantum noise intensity determination method of a quantum measurement device according to an embodiment of the present disclosure;

FIG. 4 illustrates a quantum circuit schematic for achieving maximum mixing according to an embodiment of the present disclosure;

FIG. 5 illustrates a quantum circuit schematic for obtaining a maximum superposition state according to embodiments of the present disclosure;

FIG. 6 illustrates a flow chart of a quantum measurement device error propagation method according to an embodiment of the present disclosure;

fig. 7 shows a block diagram of a quantum noise intensity determining device of a quantum measurement apparatus according to an embodiment of the present disclosure;

FIG. 8 shows a block diagram of a quantum measurement device error sustained release apparatus according to an embodiment of the present disclosure; and

Fig. 9 illustrates a block diagram of an exemplary electronic device that can be used to implement embodiments of the present disclosure.

Detailed Description

Exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings, which include various details of the embodiments of the present disclosure to facilitate understanding, and should be considered as merely exemplary. Accordingly, one of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the present disclosure. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

In the present disclosure, the use of the terms "first," "second," and the like to describe various elements is not intended to limit the positional relationship, timing relationship, or importance relationship of the elements, unless otherwise indicated, and such terms are merely used to distinguish one element from another. In some examples, a first element and a second element may refer to the same instance of the element, and in some cases, they may also refer to different instances based on the description of the context.

The terminology used in the description of the various illustrated examples in this disclosure is for the purpose of describing particular examples only and is not intended to be limiting. Unless the context clearly indicates otherwise, the elements may be one or more if the number of the elements is not specifically limited. Furthermore, the term "and/or" as used in this disclosure encompasses any and all possible combinations of the listed items.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

To date, various types of computers in use are based on classical physics as the theoretical basis for information processing, known as traditional or classical computers. Classical information systems store data or programs using binary data bits that are physically easiest to implement, each binary data bit being represented by a 0 or a1, called a bit or a bit, as the smallest unit of information. Classical computers themselves have the inevitable weakness: first, the most basic limitation of energy consumption in the calculation process. The minimum energy required by the logic element or the memory cell should be more than several times of kT to avoid malfunction under thermal expansion; secondly, information entropy and heating energy consumption; thirdly, when the wiring density of the computer chip is large, the uncertainty of momentum is large when the uncertainty of the electronic position is small according to the uncertainty relation of the Hessenberg. Electrons are no longer bound and there is a quantum interference effect that can even destroy the performance of the chip.

Quantum computers (QWs) are a class of physical devices that perform high-speed mathematical and logical operations, store and process quantum information, following quantum mechanical properties, laws. When a device processes and calculates quantum information and runs a quantum algorithm, the device is a quantum computer. Quantum computers follow unique quantum dynamics (particularly quantum interferometry) to achieve a new model of information processing. For parallel processing of computational problems, quantum computers have an absolute advantage in speed over classical computers. The transformation implemented by the quantum computer on each superposition component is equivalent to a classical computation, all of which are completed simultaneously and are superimposed according to a certain probability amplitude to give the output result of the quantum computer, and the computation is called quantum parallel computation. Quantum parallel processing greatly improves the efficiency of quantum computers so that they can perform tasks that classical computers cannot do, such as factorization of a large natural number. Quantum coherence is essentially exploited in all quantum ultrafast algorithms. Therefore, quantum parallel computation with quantum state instead of classical state can reach incomparable operation speed and information processing function of classical computer, and save a large amount of operation resources.

With the rapid development of quantum computer technology, quantum computers are increasingly used because of their powerful computing power and faster operating speeds. For example, chemical simulation refers to a process of mapping the hamiltonian of a real chemical system to a physically operable hamiltonian, and then modulating parameters and evolution time to find an eigenstate that can reflect the real chemical system. When an N-electron chemical system is simulated on a classical computer, the solution of a2 ^N -dimensional Schrodinger equation is involved, and the calculated amount increases exponentially with the increase of the electron number of the system. Classical computers therefore have very limited utility in chemical simulation problems. To break this bottleneck, one must rely on the powerful computational power of quantum computers. The quantum eigensolver algorithm (Variational Quantum Eigensolver, VQE) is a high-efficiency quantum algorithm for performing chemical simulation on quantum hardware, is one of the most promising applications of quantum computers recently, and opens up a number of new chemical research fields. However, the current-stage quantum computer measurement noise rate significantly limits the VQE capability, so the quantum measurement noise problem must be addressed first.

One core computational process of the quantum eigensolver algorithm VQE is to estimate the expectation value Tr [ Op ], where ρ is the quantum state of n-qubits (n-qubit quantum state) generated by the quantum computer, and n-qubit observables O are the hamiltonian-mapped to physically operable hamiltonian of the real chemical system. The above process is the most general form of quantum computing for extracting classical information, and has wide application, and can be considered as a core step for reading classical information from quantum information. In general, it can be assumed that O is a diagonal matrix under a calculation basis, and thus the expected value Tr [ oρ ] can be calculated theoretically by the formula (1):

Where O (i) represents the ith row and column element of O (assuming that the matrix element index starts numbering from 0). The above-described quantum computing process may be as shown in fig. 1, in which a process of generating an n-qubit quantum state ρ by a quantum computer 101 and measuring the quantum state ρ via a quantum measurement device 102 to obtain a measurement result is performed M times, the number of times M _i of outputting the result i is counted, ρ (i) ≡m _i/M is estimated, and Tr [ O ρ ] may be estimated by a classical computer 103. For example, the quantum measurement device 102 may implement measuring the n-qubit quantum state ρ by n (positive integer) single-qubit measurement devices 1021 to obtain a measurement result. The law of large numbers ensures that the estimation process described above is correct when M is sufficiently large.

It is understood that the combination of quantum computer 101 and quantum measurement device 102 is a quantum computer or quantum device in the general sense.

However, in the physical implementation, due to limitations of various factors such as instruments, methods, conditions, etc., the quantum measurement device cannot work precisely to generate measurement noise, so that the actually estimated values M _i/M and ρ (i) deviate, and errors occur in calculating Tr [ O ρ ] by using the formula (1).

The source of noise may be either classical noise or quantum noise. Specifically, for the following:

in the ideal case of a quantum measurement device without noise, the corresponding measurement POVM (Positive Operator-Valued Measure, positive operator valued measure) is expressed as:

where the index i indicates no noise (ideal). In the case of a quantum measurement device containing quantum noise, the corresponding measurement POVM (Positive Operator-Valued Measure, positive operator valued measure) is expressed as:

Wherein, The half positive matrix, superscript q, represents the quantum noise (quantum). In the case of a quantum measurement device containing only classical noise, the corresponding measurement POVM (Positive Operator-Valued Measure, positive operator valued measure) is expressed as:

Where superscript c denotes classical noise (classical). The x epsilon {0,1} ⁿ represents the output result of the quantum measurement device.

That is, there may be an error in measuring the output quantum state by the above-described measurement basis to determine the corresponding output result. Eventually, the number of times M _i that results in the statistical output result i may be inaccurate.

If quantum noise exists in the quantum measurement equipment, the quantum measurement equipment chromatographic method (Quantum Measurement Tomography) is needed to be carried out on the quantum measurement equipment to acquire all information of the noise and carry out error slow-release work; on the other hand, if only classical noise exists in the quantum measurement device, all information of the noise can be obtained and error slow-release work can be carried out only by carrying out a quantum measurement device calibration method (Quantum Measurement Calibration) on the quantum measurement device. The tomographic method can extract more information than the calibration method, but consumes more resources.

Taking a single qubit as an example, assuming that a large number of |0> states and |1> states are prepared respectively, measurement results are obtained after measurement by a quantum measurement device, and the probability of obtaining x=0 measurement results is found to be 0.9 and 0.2 respectively, and the probability of obtaining x=1 measurement results is found to be 0.1 and 0.8 respectively. The corresponding observation operators can be written:

Due to The numerical relationship between gamma ₁,γ₂ can be determined. Gamma ₁,γ₂ is the source of quantum noise here, an amount that can usually only be characterized by chromatographic methods.

The chromatography method of the quantum measurement equipment and the calibration method of the quantum measurement equipment are common techniques for carrying out error slow-release on the quantum measurement equipment.

The quantum measurement device chromatographic method prepares different input states and uses the quantum measurement device to measure, and a measurement operator pi ^q is constructed according to the statistical data. The measurement operators obtained by the chromatographic method can completely characterize the quantum noise properties of the quantum measurement device. However, although the chromatography method can completely characterize the quantum noise, the quantum state and the measurement base need to be stretched into the whole quantum space, so that the chromatography cost is very high, and the required resource is O (4 ⁿ) (n is the number of quantum bits of the quantum measurement device).

According to the quantum measurement equipment calibration method, classical matrix pi ^c is constructed by running calibration data generated by a calibration circuit, classical noise information of the noisy quantum measurement equipment is described by the matrix, and when a specific quantum calculation task needs to be executed subsequently, noise output data generated by a quantum circuit corresponding to the task can be processed by using the obtained calibration matrix pi ^c, so that errors of the output data are delayed.

For example, in the process of error-releasing a measurement device using a calibration method, in general, the measurement device may be calibrated first and then the output result of the measurement device may be corrected, and the workflow thereof may be as shown in fig. 2. In this measurement noise processing basic flow, the experimenter first prepares many calibration circuits (step 210) and then runs them in the actual measurement device (step 220) to detect the basic information of the measurement device. Specifically, a corresponding calibration circuit may be constructed by the quantum computer 101 in a system as shown in fig. 1 to obtain a corresponding standard base quantum state. The standard base quantum states are measured multiple times by the measurement device 102 to generate calibration data (step 230). Using the generated calibration data, a calibration matrix a can be constructed (step 240) that characterizes classical noise information of the noisy measurement device. Subsequently, when a specific quantum computing task needs to be executed, a quantum circuit corresponding to the computing task may be first constructed (step S10), the quantum circuit corresponding to the task is operated in an actual device (step S20), and noisy output data { M _i}_i of the quantum circuit is obtained (step S30). Subsequently, these noisy data may be post-processed using the calibration matrix a already obtained (step S40):

Where A ^-1 represents the inverse of the calibration matrix A. By approximating { ρ (i) } _i by the probability distribution p after calibration and further calculating the expected value Tr [ O ρ ] (step S50), the influence of classical noise can be effectively eliminated, thereby improving the accuracy of calculating the expected value.

Quantum measurement device calibration methods, while requiring relatively low computational resources, can only characterize classical noise. Classical noise can only reflect part of sources of noise of measuring equipment, such as statistical errors, which can be slowly released by a statistical method in subsequent data processing, however, if quantum noise of quantum measuring equipment is more remarkable, the main source of noise is quantum noise, and noise-containing measuring data obtained at the moment cannot accurately release errors of the noise-containing measuring data no matter what kind of high-definition statistical means is adopted.

Therefore, it would be necessary to efficiently and quickly estimate the quantum noise intensity in a quantum measurement device. Based on the estimated quantum noise intensity, dynamically determining whether to use a chromatography method of the quantum measurement equipment or a calibration method of the quantum measurement equipment to process the noise of the quantum measurement equipment, thereby saving resources consumed by the quantum measurement noise processing.

Embodiments according to the present disclosure provide a quantum noise intensity determination method of a quantum measurement device. As shown in fig. 3, the method 300 includes: obtaining the maximum mixed state of n quantum bits, wherein n is the quantum bit number of the quantum measurement device (step 310); repeatedly operating the quantum measuring device to measure the maximum mixed state for a first number of times to obtain a measurement result (step 320); acquiring a maximum superposition state of the n quantum bits (step 330); repeatedly operating the quantum measuring device to measure the maximum superposition state a second number of times to obtain a measurement result (step 340); respectively counting the measurement results of the maximum mixed state and the maximum overlapped state to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of at least one measurement result corresponding to the maximum overlapped state (step 350); and determining a quantum noise intensity of the quantum measurement device based on a difference between the respective first probability value and the corresponding second probability value of the at least one measurement (step 360).

According to the embodiment of the disclosure, the quantum noise intensity of the quantum measurement device can be determined efficiently, and whether all information of the quantum measurement device needs to be described by consuming more resources or not can be judged based on the determined quantum noise intensity, so that the accuracy of a calculation result is improved.

The measurement result obtained by measuring the corresponding quantum state through the quantum measurement equipment is a binary character string, namely the measurement result is x, and x epsilon {0,1} ⁿ. Different forms of x are different measurement results. The number of occurrences of the preset one or more measurements may be counted to obtain a probability distribution for the one or more measurements.

It will be appreciated that by the method described in this disclosure, the probability distribution of all measurements (x ε {0,1} ⁿ) can be determined.

Illustratively, in one embodiment according to the present disclosure, estimating the quantum noise intensity of a quantum measurement device of n quantum bits may include the steps of:

the first step: preparing the maximum mixed state: I is a2 ⁿ -dimensional identity matrix.

And a second step of: the noisy quantum measurement equipment is repeatedly operated for totally N ₁ times, and the statistical output result is the number N _x|π of binary character strings x, wherein x is {0,1} ⁿ,∑_xN_x|π＝N₁.

And a third step of: preparation of maximum superposition StateWherein (|0 … 0 > + … +|1 … 1 >) includes all forms of x ε {0,1} ⁿ.

Fourth step: the noisy measuring equipment is repeatedly operated for totally N ₂ times, and the statistical output result is the number N _x|Φ of binary character strings x, wherein x is epsilon {0,1} ⁿ,∑_xN_x|Φ＝N₂.

Fifth step: and carrying out normalization processing on the acquired data set, dividing the acquired data set by the corresponding operation times N ₁ or N ₂ of the measuring equipment to obtain probability distribution of an output result, wherein the probability distribution is as follows:

P_x|π＝N_x|π/N_shots

P_x|Φ＝N_x|Φ/N_shots

As described above, it is possible to obtain:

Wherein, Representation ofThe y-th row and z-th column elements of (c),And the same is true.

Comparing the expressions of P _x|π and P _x|Φ above, it is easy to see that the difference between the two characterizes the intensity of the quantum noise to some extent.

According to some embodiments, determining the quantum noise intensity of the quantum measurement device may include: determining an average value of the absolute values of the differences corresponding to the at least one measurement result based on the absolute values of the differences between the respective first probability values and the corresponding second probability values of the at least one measurement result; and determining a quantum noise intensity of the quantum measurement device based on the average value.

Specifically, in the above embodiment, the probability distributions corresponding to the two input states are subtracted and the absolute value is multiplied by 2 ⁿ, so as to obtain:

This value characterizes the quantum noise intensity of the output as binary string x. An experimenter can judge whether the quantum noise effect is obvious or not by setting the fault tolerance rate epsilon. For example, if g _x > ∈corresponding to the specified measurement result x, quantum noise of the quantum measurement device may be considered significant; otherwise the quantum noise of the quantum measurement device is considered insignificant. Or if g _x > ∈then quantum noise is considered significant; if g _x < <epsilon, quantum noise can be considered to be insignificant.

Additionally or alternatively, if g _x > e or g _x > e, corresponding to a certain proportion (e.g., 50%) of measurements, the quantum noise of the quantum measurement device may be considered significant; otherwise the quantum noise of the quantum measurement device is considered insignificant.

Additionally or alternatively, the average quantum noise effect of all measurements, i.e. the average of g _x, can also be calculated:

And comparing the measured value with the fault tolerance rate epsilon to judge the average quantum noise intensity of the quantum measuring equipment.

The method can be applied to all quantum measuring devices for characterizing the quantum noise intensity of the quantum measuring devices, and can be used for acquiring the quantum noise intensity even for measuring devices with insignificant quantum noise intensityThe sum of the off-diagonal elements of the quantum measuring device, i.e. the size of g _x, to determine the quantum noise strength of the quantum measuring device.

According to some embodiments, the maximum mixed state is obtained through a preset first quantum circuit. The first quantum circuit includes n qubits in a ground state, n H gates, n auxiliary qubits, and n controlled NOT gates. The n H gates act on the n qubits in the ground state respectively, and after the H gates act, controlled NOT gates act between the n qubits in the ground state and corresponding auxiliary qubits respectively, and the n qubits in the ground state and the n auxiliary qubits are in one-to-one correspondence.

In particular, the maximum mixture can be prepared by means of a "purification" process. Taking the maximum mixed state corresponding to the prepared 4 quantum bits as an example, obtaining 4 quantum bits in a ground state, and additionally introducing 4 auxiliary quantum bits. Pairing 8 qubits two by two, pairing 1 st qubit with 5 th qubit to prepare an entangled state, pairing 2 nd qubit with 6 th qubit … and so on. And finally, only half of paired qubits are observed, namely only the first 4 qubits or the last 4 qubits are observed, and the observation result corresponding to the maximum mixed state is obtained. The entangled state may be prepared by applying an H-gate to one qubit in a pair of qubits and then acting CNot gates (controlled not gates) with the other qubit, as shown in the quantum circuit diagram of fig. 4.

It will be appreciated that this is merely an exemplary method for preparing the maximum mixture, and that alternative methods for preparing the maximum mixture are also included, and are not limited to the |0> state as input and will not be described in detail herein.

According to some embodiments, the maximum superposition state is obtained by a preset second quantum circuit. The second quantum circuit includes n qubits in a ground state, and n H gates. The n H gates respectively act on the n qubits in the ground state.

Specifically, taking the preparation of the maximum superposition state corresponding to the 4 qubits as an example, the preparation of the maximum superposition state may be obtained by adding H gates to the 4 qubits in the ground state, as shown in the quantum circuit diagram in fig. 5.

It will be appreciated that this is merely an exemplary method for preparing the maximum stack state, and that alternative methods for preparing the maximum stack state are also included, and are not limited to the |0> state as input and will not be described in detail herein.

In one exemplary application of the method according to the embodiments of the present disclosure, a quantum noise intensity determination method according to the embodiments of the present disclosure is tested by the available quantum computer 1 and quantum computer 2. Illustratively, experiments were performed with 4 qubits selected and the maximum mixed state and the maximum superimposed state were prepared according to the related examples described above. After normalizing the data returned by the quantum measurement device, the data results shown in table 1 are obtained.

It can be seen that the quantum noise effect is more pronounced for most of the measurements for the quantum computer 1, the average quantum noise intensityMuch larger than the fault tolerance e=0.1 set in usual experiments. This means that the quantum effect is more pronounced in the noise of the quantum measuring device of the quantum computer 1, so that the quantum measuring device chromatography method is more suitable for the quantum computer 1. While for quantum computer 2, the quantum noise of most measurements is not apparent, the average quantum noise intensityMuch smaller than the fault tolerance e=0.1 set in usual experiments. This means that the quantum effect is not significant in the noise of the quantum measuring device of the quantum computer 2, and is more suitable for the quantum measuring device calibration method.

Thus, as shown in fig. 6, there is also provided a quantum measurement device error sustained release method 600, according to an embodiment of the present disclosure, comprising: determining a quantum noise intensity of the quantum measurement device (step 610); and determining, based on the determined quantum noise intensity, a corresponding one of a quantum measurement device tomography method and a quantum measurement device calibration method to perform an erroneous sustained release on the quantum measurement device (step 620). The quantum noise intensity of the quantum measurement device may be determined based on the method described in any of the embodiments above.

For example, in determining that the quantum noise intensity of the quantum measurement device is significant by the method described in the above embodiments (corresponding g _x orGreater than or far greater than a preset fault tolerance rate epsilon), carrying out error slow release on the quantum measurement equipment by a chromatographic method of the quantum measurement equipment; otherwise, carrying out error slow release on the quantum measurement equipment by a quantum measurement equipment calibration method.

As shown in fig. 7, there is also provided a quantum noise intensity determining apparatus 700 of a quantum measurement device according to an embodiment of the present disclosure, including: a first obtaining unit 710 configured to obtain a maximum mixed state of n qubits, where n is a number of qubits of the quantum measurement device; a first measurement unit 720 configured to repeatedly run the quantum measurement device to measure the maximum mixed state for a first number of times to obtain a measurement result; a second obtaining unit 730 configured to obtain a maximum superposition state of the n quantum bits; a second measurement unit 740 configured to repeatedly operate the quantum measurement device to perform measurement for a second number of times on the maximum superposition state, so as to obtain a measurement result; a statistics unit 750 configured to respectively count the measurement results of the maximum mixed state and the maximum overlapped state, so as to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of at least one measurement result corresponding to the maximum overlapped state; and a first determination unit 760 configured to determine a quantum noise intensity of the quantum measurement device based on a difference between the respective first probability value and the corresponding second probability value of the at least one measurement result.

Here, the operations of the above-described units 710 to 760 of the quantum noise intensity determining apparatus 700 of the quantum measurement device are similar to the operations of the steps 310 to 360 described above, respectively, and are not repeated here.

As shown in fig. 8, according to an embodiment of the present disclosure, there is also provided a quantum measurement device error sustained release apparatus 800, including: a second determining unit 810 configured to determine a quantum noise intensity of the quantum measurement device; and a third determining unit 820 configured to determine, based on the determined quantum noise intensity, that the quantum measurement device is to be erroneously delayed by a corresponding one of a quantum measurement device tomographic method and a quantum measurement device calibration method. The quantum noise intensity of the quantum measurement device may be determined based on the method described in any of the embodiments above.

According to embodiments of the present disclosure, there is also provided an electronic device, a readable storage medium and a computer program product.

Referring to fig. 9, a block diagram of an electronic device 900 that may be a server or a client of the present disclosure, which is an example of a hardware device that may be applied to aspects of the present disclosure, will now be described. Electronic devices are intended to represent various forms of digital electronic computer devices, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the disclosure described and/or claimed herein.

As shown in fig. 9, the electronic device 900 includes a computing unit 901 that can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM) 902 or a computer program loaded from a storage unit 908 into a Random Access Memory (RAM) 903. In the RAM903, various programs and data required for the operation of the electronic device 900 can also be stored. The computing unit 901, the ROM 902, and the RAM903 are connected to each other by a bus 904. An input/output (I/O) interface 905 is also connected to the bus 904.

A number of components in the electronic device 900 are connected to the I/O interface 905, including: an input unit 906, an output unit 907, a storage unit 908, and a communication unit 909. The input unit 906 may be any type of device capable of inputting information to the electronic device 900, the input unit 906 may receive input numeric or character information and generate key signal inputs related to user settings and/or function control of the electronic device, and may include, but is not limited to, a mouse, a keyboard, a touch screen, a trackpad, a trackball, a joystick, a microphone, and/or a remote control. The output unit 907 may be any type of device capable of presenting information and may include, but is not limited to, a display, speakers, video/audio output terminals, vibrators, and/or printers. Storage unit 908 may include, but is not limited to, magnetic disks, optical disks. The communication unit 909 allows the electronic device 900 to exchange information/data with other devices through a computer network such as the internet and/or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers and/or chipsets, such as bluetooth (TM) devices, 802.11 devices, wiFi devices, wiMax devices, cellular communication devices, and/or the like.

The computing unit 901 may be a variety of general and/or special purpose processing components having processing and computing capabilities. Some examples of computing unit 901 include, but are not limited to, a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), various specialized Artificial Intelligence (AI) computing chips, various computing units running machine learning model algorithms, a Digital Signal Processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 901 performs the various methods and processes described above, such as method 200 or 600. For example, in some embodiments, the method 200 or 600 may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as the storage unit 908. In some embodiments, part or all of the computer program may be loaded and/or installed onto the electronic device 900 via the ROM 902 and/or the communication unit 909. When the computer program is loaded into RAM 903 and executed by computing unit 901, one or more steps of method 200 or 600 described above may be performed. Alternatively, in other embodiments, computing unit 901 may be configured to perform method 200 or 600 by any other suitable means (e.g., by means of firmware).

Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuit systems, field Programmable Gate Arrays (FPGAs), application Specific Integrated Circuits (ASICs), application Specific Standard Products (ASSPs), systems On Chip (SOCs), complex Programmable Logic Devices (CPLDs), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include: implemented in one or more computer programs, the one or more computer programs may be executed and/or interpreted on a programmable system including at least one programmable processor, which may be a special purpose or general-purpose programmable processor, that may receive data and instructions from, and transmit data and instructions to, a storage system, at least one input device, and at least one output device.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of this disclosure, a machine-readable medium may be a tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and pointing device (e.g., a mouse or trackball) by which a user can provide input to the computer. Other kinds of devices may also be used to provide for interaction with a user; for example, feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form, including acoustic input, speech input, or tactile input.

The systems and techniques described here can be implemented in a computing system that includes a background component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a user computer having a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such background, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: local Area Networks (LANs), wide Area Networks (WANs), and the internet.

The computer system may include a client and a server. The client and server are typically remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server may be a cloud server, a server of a distributed system, or a server incorporating a blockchain.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps recited in the present disclosure may be performed in parallel, sequentially or in a different order, provided that the desired results of the disclosed aspects are achieved, and are not limited herein.

Although embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it is to be understood that the foregoing methods, systems, and apparatus are merely exemplary embodiments or examples, and that the scope of the present invention is not limited by these embodiments or examples but only by the claims following the grant and their equivalents. Various elements of the embodiments or examples may be omitted or replaced with equivalent elements thereof. Furthermore, the steps may be performed in a different order than described in the present disclosure. Further, various elements of the embodiments or examples may be combined in various ways. It is important that as technology evolves, many of the elements described herein may be replaced by equivalent elements that appear after the disclosure.

Claims

1. A method of quantum noise intensity determination for a quantum measurement device, comprising:

obtaining the maximum mixed state of n quantum bits, wherein n is the quantum bit number of the quantum measurement equipment;

repeatedly operating the quantum measurement equipment to measure the maximum mixed state for a first number of times so as to obtain a measurement result;

Obtaining the maximum superposition state of n quantum bits;

repeatedly operating the quantum measurement equipment to measure the maximum superposition state for a second number of times so as to obtain a measurement result;

Respectively counting the measurement results of the maximum mixed state and the maximum overlapped state to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of at least one measurement result corresponding to the maximum overlapped state; and

A quantum noise intensity of the quantum measurement device is determined based on a difference between the respective first probability value and the corresponding second probability value of the at least one measurement.

2. The method of claim 1, wherein determining the quantum noise intensity of the quantum measurement device comprises:

Determining an average value of the absolute values of the differences corresponding to the at least one measurement result based on the absolute values of the differences between the respective first probability values and the corresponding second probability values of the at least one measurement result; and

A quantum noise intensity of the quantum measurement device is determined based on the average value.

3. The method of claim 1, wherein the maximum mixing state is obtained by a preset first quantum circuit, wherein,

The first quantum circuit includes n qubits in a ground state, n H gates, n auxiliary qubits, and n controlled not gates, and wherein,

The n H gates act on the n qubits in the ground state respectively, and after the H gates act, controlled NOT gates act between the n qubits in the ground state and corresponding auxiliary qubits respectively, and the n qubits in the ground state and the n auxiliary qubits are in one-to-one correspondence.

4. The method of claim 1 or 3, wherein the maximum superposition state is obtained by a preset second quantum circuit, wherein,

The second quantum circuit includes n qubits in a ground state, and n H gates, and wherein,

The n H gates respectively act on the n qubits in the ground state.

5. A method for error sustained release of a quantum measurement device, comprising:

Determining a quantum noise intensity of the quantum measurement device; and

Based on the determined quantum noise intensity, determining corresponding methods in a chromatography method of the quantum measurement equipment and a calibration method of the quantum measurement equipment to perform error slow-release on the quantum measurement equipment,

Wherein the quantum noise intensity of the quantum measurement device is determined based on the method of any of claims 1-4.

6. A quantum noise intensity determining apparatus of a quantum measurement device, comprising:

A first acquisition unit configured to acquire a maximum mixed state of n qubits, where n is a number of qubits of the quantum measurement device;

A first measurement unit configured to repeatedly operate the quantum measurement device to measure the maximum mixed state for a first number of times to obtain a measurement result;

the second acquisition unit is configured to acquire the maximum superposition state of the n quantum bits;

A second measurement unit configured to repeatedly operate the quantum measurement device to perform measurement for a second number of times on the maximum superposition state to obtain a measurement result;

The statistics unit is configured to respectively count the measurement results of the maximum mixed state and the maximum superposition state so as to obtain a first probability value of each occurrence of at least one measurement result of the maximum mixed state and a second probability value of each occurrence of at least one measurement result corresponding to the maximum superposition state; and

A first determination unit configured to determine a quantum noise intensity of the quantum measurement device based on a difference between a respective first probability value and a corresponding second probability value of the at least one measurement result.

7. The apparatus of claim 6, wherein the determining unit comprises:

Means for determining an average value of the absolute values of the differences corresponding to the at least one measurement based on the absolute values of the differences between the respective first probability values and the corresponding second probability values of the at least one measurement; and

Means for determining a quantum noise intensity of the quantum measurement device based on the average value.

8. The apparatus of claim 6, wherein the maximum mixing state is obtained by a preset first quantum circuit, wherein,

9. The apparatus of claim 6 or 8, wherein the maximum superposition state is obtained by a preset second quantum circuit, wherein,

The n H gates respectively act on the n qubits in the ground state.

10. An error sustained release apparatus of a quantum measurement device, comprising:

A second determination unit configured to determine a quantum noise intensity of the quantum measurement device; and

A third determination unit configured to determine, based on the determined quantum noise intensity, that the quantum measurement device is erroneously delayed by a corresponding one of a quantum measurement device tomographic method and a quantum measurement device calibration method,

11. An electronic device, comprising:

At least one processor; and

A memory communicatively coupled to the at least one processor; wherein the method comprises the steps of

The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-5.

12. A non-transitory computer readable storage medium storing computer instructions for causing the computer to perform the method of any one of claims 1-5.

13. A computer program product comprising a computer program, wherein the computer program, when executed by a processor, implements the method of any of claims 1-5.