CN114897175A

CN114897175A - Noise elimination method and device for quantum measurement equipment, electronic equipment and medium

Info

Publication number: CN114897175A
Application number: CN202210615238.XA
Authority: CN
Inventors: 王琨; 郑聪聪
Original assignee: Beijing Baidu Netcom Science and Technology Co Ltd
Current assignee: Beijing Baidu Netcom Science and Technology Co Ltd
Priority date: 2022-05-31
Filing date: 2022-05-31
Publication date: 2022-08-12

Abstract

The present disclosure provides a method and an apparatus for eliminating noise of a quantum measurement device, an electronic device, a computer-readable storage medium, and a computer program product, and relates to the field of quantum computers, in particular to the field of quantum noise slow release technology. The implementation scheme is as follows: performing a first operation for a first preset number of times to determine an average probability value of respective occurrences of at least one measurement, the first operation comprising the steps of: obtaining a quantum state rho of an n quantum bit to be measured; randomly selecting n times in a set { single-bit Pally X gate and single-bit Pay Y gate } to obtain n Pay gates; respectively acting n Pagli gates on each quantum bit of the quantum state rho to repeatedly operate quantum measurement equipment to measure the quantum state after the action for a second preset number of times, and turning the state of each bit of the obtained measurement result; and counting the measurement results after the state is turned over to determine the probability value of each occurrence of at least one measurement result.

Description

Noise elimination method and device for quantum measurement equipment, electronic equipment and medium

Technical Field

The present disclosure relates to the field of quantum computers, and in particular, to a method and an apparatus for eliminating noise of a quantum measurement device, an electronic device, a computer-readable storage medium, and a computer program product.

Background

Quantum computer technology has developed rapidly in recent years, but noise problems in quantum computers are inevitable in the foreseeable future: the heat dissipation in the qubit or the random fluctuations generated in the underlying quantum physical process will cause the state of the qubit to flip or randomize, and the measurement device will read the calculation results with deviations, which may cause the calculation process to fail.

Specifically, due to the limitations of various factors such as instruments, methods, conditions, etc., quantum measurement equipment cannot work precisely, so that measurement noise is generated, and deviation occurs in an actual measurement value. Therefore, it is generally 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 noise cancellation method of a quantum measurement device, an apparatus, an electronic device, a computer-readable storage medium, and a computer program product.

According to an aspect of the present disclosure, there is provided a quantum noise cancellation method of a quantum measurement apparatus, including: performing a first operation for a first preset number of times to determine an average probability value of each occurrence of at least one measurement result as a measurement result obtained after quantum noise is eliminated, wherein the first operation comprises the following steps: obtaining quantum state rho of n quantum bits to be measured, wherein n is a positive integer; randomly selecting n times in a Paly gate set { single-bit Pay X gate, single-bit Pay Y gate } to obtain n Pay gates; respectively acting the n Pauli gates on each quantum bit of the quantum state rho to obtain an acted quantum state; repeatedly operating the quantum measurement equipment to measure the acted quantum state for a second preset number of times, and turning the state of each bit of the obtained measurement result in the form of a binary character string; and counting the measurement results after the state is turned over to determine the probability value of each occurrence of the at least one measurement result.

According to another aspect of the present disclosure, there is provided a noise cancellation method of a quantum measurement apparatus, including: obtaining quantum state rho of n quantum bits to be measured, wherein n is a positive integer; determining a measurement result corresponding to the quantum state rho after quantum noise of the quantum measurement equipment is eliminated; obtaining a measurement result corresponding to the quantum state rho after classical noise elimination based on a quantum measurement device calibration method and the measurement result, wherein the measurement result corresponding to the quantum state rho after quantum noise elimination of the quantum measurement device is determined according to the method disclosed by the present disclosure.

According to another aspect of the present disclosure, there is provided a quantum noise cancellation device of a quantum measurement apparatus, including: a first determining unit configured to perform a first operation for a first preset number of times to determine an average probability value of each occurrence of at least one measurement result as a measurement result obtained after quantum noise is removed, wherein the first operation comprises the following steps: obtaining quantum state rho of n quantum bits to be measured, wherein n is a positive integer; randomly selecting n times in a Paly gate set { single-bit Pay X gate, single-bit Pay Y gate } to obtain n Pay gates; respectively acting the n Pauli gates on each quantum bit of the quantum state rho to obtain an acted quantum state; repeatedly operating the quantum measurement equipment to measure the acted quantum state for a second preset number of times, and turning the state of each bit of the obtained measurement result in the form of a binary character string; and counting the measurement results after the state is turned over to determine the probability value of each occurrence of the at least one measurement result.

According to another aspect of the present disclosure, there is provided a noise removing device of a quantum measuring apparatus, including: a first acquisition unit configured to acquire a quantum state ρ of n qubits to be measured, where n is a positive integer; a second determination unit configured to determine a measurement result corresponding to the quantum state ρ after quantum noise of the quantum measurement device is eliminated; a second obtaining unit configured to obtain, based on a quantum measurement device calibration method and the measurement result, a measurement result corresponding to the quantum state ρ after removal of classical noise, wherein the measurement result corresponding to the quantum state ρ after removal of quantum noise of the quantum measurement device is determined according to the method of the present disclosure.

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 cause the at least one processor to perform the method of 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 disclosure, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the method described in the disclosure.

According to one or more embodiments of the present disclosure, quantum noise in the quantum measurement device can be efficiently eliminated by the action of the pauli X gate and the pauli Y gate, so that only classical noise is included, and a quantum measurement device calibration technique that saves more computational resources can be selected to further perform error slow release on the quantum measurement device.

It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present disclosure, nor do they limit the scope of the present disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the embodiments and, together with the description, serve to explain the exemplary implementations of the embodiments. The illustrated embodiments are for purposes of illustration only and do not limit the scope of the claims. Throughout the drawings, identical reference numbers 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, according to an embodiment of the present disclosure;

FIG. 2 shows a flow chart for error mitigation by a quantum measurement device calibration method;

FIG. 3 shows a modeling schematic of a noisy quantum measurement device according to an embodiment of the present disclosure;

fig. 4 shows a PTM matrix diagram corresponding to a two-bit noisy quantum measurement device according to an embodiment of the present disclosure;

FIG. 5 illustrates an operational schematic diagram of compiling a quantum measurement device according to an embodiment of the disclosure;

fig. 6A and 6B show PTM matrix diagrams before and after compiling a quantum measurement device, respectively, according to an embodiment of the present disclosure;

FIG. 7 shows a flow diagram of a quantum noise cancellation method of a quantum measurement device according to an embodiment of the present disclosure;

fig. 8 and 9 show PTM matrix diagrams before and after compiling two different quantum devices, respectively, according to an embodiment of the present disclosure;

FIG. 10 shows a flow diagram of a noise cancellation method of a quantum measurement device according to an embodiment of the present disclosure;

fig. 11 shows a block diagram of a structure of a quantum noise cancellation device of a quantum measurement apparatus according to an embodiment of the present disclosure;

fig. 12 shows a block diagram of a noise cancellation arrangement of a quantum measurement device according to an embodiment of the present disclosure; and

FIG. 13 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 with reference to the accompanying drawings, in which various details of the embodiments of the disclosure are included to assist understanding, and which are to be considered as merely exemplary. Accordingly, those 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, unless otherwise specified, the use of the terms "first", "second", etc. to describe various elements is not intended to limit the positional relationship, the timing relationship, or the importance relationship of the elements, and such terms are used only 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, based on the context, they may also refer to different instances.

The terminology used in the description of the various described 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, if the number of elements is not specifically limited, the elements may be one or more. Furthermore, the term "and/or" as used in this disclosure is intended to encompass 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, the various types of computers in use are based on classical physics as the theoretical basis for information processing, called traditional computers or classical computers. Classical information systems store data or programs using the most physically realizable binary data bits, each represented by a 0 or 1, called a bit or bit, as the smallest unit of information. The classic computer itself has inevitable weaknesses: one is the most fundamental limitation of computing process energy consumption. The minimum energy required by the logic element or the storage unit is more than several times of kT so as to avoid the misoperation of thermal expansion and dropping; information entropy and heating energy consumption; thirdly, when the wiring density of the computer chip is high, the uncertainty of the electronic position is small and the uncertainty of the momentum is large according to the heisenberg uncertainty relation. The electrons are no longer bound and there are quantum interference effects that can even destroy the performance of the chip.

Quantum computers (quantum computers) are physical devices that perform high-speed mathematical and logical operations, store and process quantum information in compliance with quantum mechanical properties and laws. When a device processes and calculates quantum information and runs quantum algorithms, the device is a quantum computer. Quantum computers follow a unique quantum dynamics law, particularly quantum interference, to implement 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 of each superposed component by the quantum computer is equivalent to a classical calculation, all the classical calculations are completed simultaneously and superposed according to a certain probability amplitude to give an output result of the quantum computer, and the calculation is called quantum parallel calculation. Quantum parallel processing greatly improves the efficiency of quantum computers, allowing them to accomplish tasks that classic computers cannot accomplish, such as factorization of a large natural number. Quantum coherence is essentially exploited in all quantum ultrafast algorithms. Therefore, quantum parallel computation of a classical state is replaced by a quantum state, so that the computation speed and the information processing function which are incomparable with a classical computer can be achieved, and meanwhile, a large amount of computation resources are saved.

With the rapid development of quantum computer technology, the application range of quantum computers is wider and wider due to the strong computing power and the faster operation speed. For example, chemical simulation refers to a process of mapping the hamiltonian of a real chemical system to physically operable hamiltonian, and then modulating parameters and evolution times to find eigenstates that reflect the real chemical system. When simulating an N-electron chemistry system on a classical computer, 2 is involved ^N The calculation amount of the Weischrodinger equation is exponentially increased along with the increase of the system electron number. Classical computers have therefore had very limited effect on chemical simulation problems. To break through this bottleneck, the powerful computing power of quantum computers must be relied upon. A Quantum intrinsic solver (VQE) algorithm is an efficient Quantum algorithm for performing chemical simulation on Quantum hardware, is one of the most promising applications of Quantum computers in the near future, and opens up many new chemical research fields. But now at the stageThe quantum computer measurement noise ratio significantly limits the capability of VQE, so the quantum measurement noise problem must first be addressed.

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

where O (i) denotes the ith row and ith column element of O (assuming the matrix element index is numbered starting from 0). The above quantum computing process may be as shown in fig. 1, in which a process of generating n qubit quantum states ρ by a quantum computer 101 and measuring the quantum states ρ via a quantum measurement device 102 to obtain a measurement result is performed M times, and the number M of times of outputting a result i is counted _i Estimate ρ (i) ≈ M _i Per, Tr [ O ρ ] can be estimated by classical computer 103]. Illustratively, the quantum measurement device 102 may implement the measurement of the n qubit quantum states 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 is correct when M is sufficiently large.

It will be appreciated 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 physical implementation, due to the limitations of various factors such as instruments, methods, conditions, and the like, quantum measurement equipment cannot work precisely, thereby generating measurement noise, so that the value M actually estimated _i There is a deviation of/M and ρ (i) resulting in the calculation of T using equation (1)r[Oρ]An error occurs.

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

under the ideal condition that the quantum measurement device does not contain noise, the corresponding measurement POVM (Positive Operator-Valued measurement) is expressed as follows:

where the superscript i indicates no noise (ideal). Under the condition that quantum measurement equipment contains quantum noise, the corresponding measurement POVM (Positive Operator-Valued Measure) is expressed as follows:

wherein the content of the first and second substances,

being a semi-positive definite matrix, superscript q denotes quantum noise (quantum). Under the condition that the quantum measuring equipment only contains classical noise, corresponding POVM (Positive Operator-value Measure) is measuredThe value measure) is expressed as:

where the superscript c denotes classical noise (classical). The x is formed by {0,1} ⁿ And represents the output result of the quantum measurement device.

That is, there may be errors in measuring the output quantum states by the measurement basis described above to determine the corresponding output results. Finally, the number M of times leading to a statistical output i _i May be inaccurate.

If Quantum noise exists in the Quantum measuring equipment, a Quantum measuring equipment chromatography method (Quantum Measurement mobility) must be carried out on the Quantum measuring equipment to obtain 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 acquired and error slow release work can be performed only by performing a Quantum Measurement device Calibration method (Quantum Measurement Calibration) on the Quantum Measurement device. Chromatography methods can extract more information, but consume more resources, than calibration methods.

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

due to the fact that

Can determine gamma ₁ ,γ ₂ A numerical relationship therebetween. Here γ is ₁ ,γ ₂ Is the source of quantum noise and is a quantity that can usually only be characterized by chromatographic methods.

The chromatography method and calibration method of quantum measurement equipment are common techniques for error slow release of quantum measurement equipment.

The quantum measuring equipment chromatography method prepares different input states, measures by using the quantum measuring equipment, and constructs a measurement operator pi according to statistical data ^q . The measurement operator obtained by the chromatography method can completely characterize the quantum noise property of the quantum measurement device. However, although the chromatography method can completely map quantum noise, the quantum state and the measurement basis need to be stretched into the whole quantum space, so the chromatography is very expensive, and the required resource is O (4) ⁿ ) (n is the number of quantum bits of the quantum measurement device).

The calibration method of the quantum measurement equipment constructs a classic matrix II through calibration data generated by operating a calibration circuit ^c The matrix depicts classical noise information of the noisy quantum measurement device, and the obtained calibration matrix II can be utilized when a specific quantum calculation task needs to be executed subsequently ^c And processing the noisy output data generated by the quantum circuit corresponding to the task so as to slowly release the error of the output data.

For example, in the process of performing error mitigation on the measurement device by using the calibration method, generally, the measurement device may be calibrated first and then the output result of the measurement device may be corrected, and the workflow may be as shown in fig. 2. In this basic flow of measurement noise processing, an experimenter first prepares a number of calibration circuits (step 210), and then runs the calibration circuits in an actual measurement device (step 220) to detect basic information of the measurement device. In particular, it may be constructed by a quantum computer 101 in a system as shown in FIG. 1And calibrating the circuit accordingly to obtain the corresponding standard basis quantum state. The standard basis quantum states are measured by measurement device 102 a plurality of times 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), and the quantum circuit corresponding to the task is operated in an actual device (step S20), and the noisy output data { M } of the quantum circuit is obtained _i } _i (step S30). Subsequently, these noisy data may be post-processed using the obtained calibration matrix a (step S40):

wherein A is ^-1 Representing the inverse of the calibration matrix a. Approximating { ρ (i) }by the probability distribution p after calibration _i Further, an expected value Tr [ O ρ ] is calculated](step S50), the influence of the classical noise can be effectively eliminated, thereby improving the accuracy of calculating the expected value.

Although the quantum measurement device calibration method requires relatively low computational resources, only classical noise can be characterized. The classical noise can only reflect part of sources of noise of the measuring equipment, for example, noise which can be slowly released by a statistical method in subsequent data processing such as statistical errors, however, if the quantum noise of the quantum measuring equipment is significant, the main source of the noise is the quantum noise, and the obtained noisy measuring data cannot accurately slowly release the errors no matter what kind of high-level statistical means is used.

Thus, it is contemplated that quantum noise in the quantum measurement device may be removed or cancelled, such that the remainder is classical noise. Then, the classical noise of the quantum measurement device can be processed by using the quantum measurement device calibration technology, so that the resource consumed by the quantum measurement noise processing is saved.

According to an embodiment of the present disclosure, there is provided a quantum noise cancellation method of a quantum measurement apparatus, including: performing a first operation for a first preset number of times to determine an average probability value of each occurrence of at least one measurement result as a measurement result obtained after quantum noise is eliminated, wherein the first operation comprises the following steps: obtaining quantum state rho of n quantum bits to be measured, wherein n is a positive integer; randomly selecting n times in a Paly gate set { single-bit Pay X gate, single-bit Pay Y gate } to obtain n Pay gates; respectively acting the n Pauli gates on each quantum bit of the quantum state rho to obtain an acted quantum state; repeatedly operating the quantum measurement equipment to measure the acted quantum state for a second preset number of times, and turning the state of each bit of the obtained measurement result in the form of a binary character string; and counting the measurement results after the state is reversed to determine a probability value of each occurrence of the at least one measurement result.

According to the embodiment of the disclosure, quantum noise in the quantum measurement device can be efficiently eliminated through the action of the pauli X gate and the pauli Y gate, so that only classical noise is contained, and a quantum measurement device calibration technology which saves more computing resources can be selected to further carry out error slow release on the quantum measurement device.

In the present disclosure, for a noisy quantum measurement device, as shown in fig. 3, it can be modeled as a combination of a noisy channel 301 and an ideal measurement device 302, and the input quantum state may be disturbed by the noisy channel 301 and then measured by the ideal measurement device 302, resulting in an error in the measurement result. Typically, POVM II may be used _x } _x To describe the noisy quantum measuring device, wherein II _x Representing the observation operator corresponding to the output x. Equivalently, the measurement process can be viewed as a special quantum-classical channel (the input to the channel is the quantum state and the output is the classical state), having the form:

suppose that

Is a set of orthogonal bases of an n-bit operator space, the quantum state ρ can be represented as:

α _i ＝Tr[P _i ρ]

under the expression Pauli Transfer Matrix (PTM), the following expression exists:

wherein gamma is 4 ⁿ ×4 ⁿ The real number matrix of (2) can completely describe the information of the quantum channel.

Thus, under the expression Pauli Transfer Matrix (PTM), the quantum-classical channel can be represented as a 4 ⁿ ×4 ⁿ Of (2) matrix

The ith row and jth column elements of the matrix are:

wherein, P _i 、P _j The ith and jth n-qubit Pauli operators, respectively.

Under the PTM expression, when only classical noise exists in the quantum measuring equipment, only part of elements in the PTM matrix are nonzero values; but if quantum noise is present in the quantum measurement device, there will be more elements that are non-zero values. Taking a two-bit noisy quantum measurement device as an example, the effect of quantum noise and classical noise on the measurement channel can be shown in fig. 4. Fig. 4 shows a PTM matrix of quantum channels of a two-qubit quantum measurement device, where the light grey part is the element that can be affected by quantum noise and the dark grey part is the element that can be affected by classical noise. To convert quantum noise to classical noise (or to eliminate it), all light gray part elements need to be erased (i.e. initialized to zero).

In the present disclosure, all light gray part elements in the PTM may be erased by an XY twining (XY flip) technique, thereby converting the quantum noise into the classical noise. Specifically, the technique randomly selects a Pauli X operator or Pauli Y operator (hence the name XY Twirling) before and after the quantum measurement device, and inserts the Pauli X operator or Pauli Y operator into a measurement circuit for compiling. The Pauli X operator and Pauli Y operator are shown below:

the corresponding compiling process is expressed mathematically as:

wherein, M' represents the quantum measurement channel after XY Twirling. It can be shown that the new measurement channel M' thus obtained contains only classical noise. As shown in fig. 5, before and after the noisy quantum measurement device, a Pauli operator obtained by random sampling is applied, where the former Pauli operator may be implemented by using a corresponding Pauli gate, and the latter Pauli operator may be implemented by "flipping" an output bit string.

The present disclosure can convert the influence of quantum noise generation into the influence of classical noise using XY Twirling technology. It may be noted that quantum noise may be removed after compiling by XY Twirling technique in the present disclosure, but classical noise may be unchanged or may be changed. In the example shown in fig. 3, the XY Twirling technique would erase all elements corresponding to the dark gray portions.

Illustratively, the correctness of XY Twirling can be demonstrated by numerical simulation. First, a group of noisy POVMs is randomly generated, and a corresponding PTM matrix is obtained by calculation, as shown in fig. 6A. The processed PTM matrix is obtained by compiling by XY Twirling technique, and the simulation result thereof can be shown in fig. 6B. As can be seen from fig. 6A and 6B, all elements corresponding to quantum noise are erased, and the remaining elements correspond to classical noise.

In particular, fig. 7 shows a flow diagram of a quantum noise cancellation method of a quantum measurement device according to an embodiment of the present disclosure. As shown in fig. 7, the following first operation is performed a first preset number of times (step 710): acquiring quantum state rho of n qubits to be measured, wherein n is a positive integer (step 7101); randomly selecting n times in a Pally gate set { single-bit Pally X gate, single-bit Pay Y gate } to obtain n Pay gates (step 7102); respectively acting n pauli gates on each qubit of the quantum state ρ to obtain an acted quantum state (step 7103); repeatedly operating the quantum measurement device to measure the acted quantum state for a second preset number of times, and performing state inversion on each bit of the obtained measurement result in the form of the binary character string (step 7104); and counting the measurement results after the state is reversed to determine a probability value of each occurrence of at least one measurement result (step 7105); an average probability value of each occurrence of at least one measurement result is determined based on all probability values corresponding to each of the at least one measurement result obtained after the first operation for the first preset number of times (step 720).

According to some embodiments, the first preset number is not less than 2 ⁿ . When the first preset times is not less than 2 ⁿ When the first preset number is more than 2, the exhaustion effect can be achieved ⁿ And certain redundancy exists), so that the measurement result is closer to the measurement result after quantum noise is eliminated, and the accuracy of the measurement result is improved. Of course, the first preset number of times may be less than 2 ⁿ This may cause partial errors in the measurement results. Therefore, the designer can set the box according to specific requirementsAn appropriate first predetermined sub-value.

In an exemplary embodiment according to the present disclosure, quantum noise in a quantum measurement device may be eliminated by the following steps.

In step 1, input n qubits of quantum state ρ, randomly select n Pauli gates from the set of single-bit Pauli gates { X, Y }, and label them as { P } ₁ ,P ₂ ,...,P _n }。

In step 2, { P } ₁ ,P ₂ ,...,P _n Sequentially acting on n quantum bits of the quantum state rho, and then performing M by using a quantum measurement device containing noise _shots Measuring, and performing state reversal on each binary string output result x, and recording as

Statistical output of results

Number of times of

In step 3, the statistical result is used to obtain the estimation result

In step 4, repeating the steps 1-3N times, and recording the ith statistical result as

Obtaining an average probability distribution:

wherein the content of the first and second substances,

i.e. the measurement result obtained by measuring the input quantum state rho after eliminating the quantum noise, and the measurementThe quantitative results contain only the effects of classical noise.

Theoretically, the quantum measurement noise processing scheme is applicable to all quantum measurement devices, can convert quantum noise contained in the quantum measurement devices into classical noise, and can calibrate data by using a classical noise processing method, so that the consumption of quantum resources is reduced.

In one exemplary application of the method according to the embodiments of the present disclosure, the method of the embodiments of the present disclosure was tested with respect to IBM's 5 qubit (IBM Quito) true machine and IBM's FakeMontreal 63 qubit simulator, where the FakeMontreal noisy simulator is a simulator corresponding to IBM Montreal superconducting quantum computer, whose noise data largely restores the noise data of the true machine. Illustratively, taking 2 qubits as an example, stochastic coding is performed according to the method described above, and probe Tomography (Detector tomogry) is used to obtain a pomm element (complex modulo length), and the pomm element is compared with the pomm element before stochastic coding. The comparison results of the FakeMontreal 63 qubit simulator and the 5 qubit (IBM Quito) true machine are shown in FIGS. 8 and 9, respectively. In fig. 8 and 9, the first line is illustrated as a pomm element before random compilation, the second line is illustrated as a pomm element after random compilation, and the third line is an element difference between the pomm elements before and after random compilation.

According to the embodiment of the disclosure, a noise elimination method of the quantum measurement equipment is also provided. Fig. 10 shows a flow diagram of a noise cancellation method of a quantum measurement device according to an embodiment of the present disclosure. As shown in fig. 10, the method 1000 includes: acquiring quantum states rho of n quantum bits to be measured, wherein n is a positive integer (step 1010); determining a measurement result corresponding to the quantum state p after eliminating quantum noise of the quantum measurement device (step 1020); and obtaining a measurement result corresponding to the quantum state rho after the classical noise is eliminated based on the quantum measurement equipment calibration method and the measurement result (step 1030). The measurement result corresponding to the quantum state ρ after the quantum noise of the quantum measurement device is removed may be determined according to the method of any of the above embodiments.

It will be appreciated that the quantum measurement device calibration method herein may be any suitable calibration method, such as the method described above with reference to fig. 2, and is not limited thereto.

According to an embodiment of the present disclosure, as shown in fig. 11, there is also provided a quantum noise cancellation device 1100 of a quantum measurement apparatus, including: a first determining unit 1110 configured to perform a first operation for a first preset number of times to determine an average probability value of each occurrence of at least one measurement result as a measurement result obtained after quantum noise is removed, wherein the first operation includes the following steps: obtaining quantum state rho of n quantum bits to be measured, wherein n is a positive integer; randomly selecting n times in a Paly gate set { single-bit Pay X gate, single-bit Pay Y gate } to obtain n Pay gates; respectively acting the n Pauli gates on each quantum bit of the quantum state rho to obtain an acted quantum state; repeatedly operating the quantum measurement equipment to measure the acted quantum state for a second preset number of times, and turning the state of each bit of the obtained measurement result in the form of a binary character string; and counting the measurement results after the state is turned over to determine the probability value of each occurrence of the at least one measurement result.

Here, the operations of the above units of the quantum noise cancellation device 1100 of the quantum measurement apparatus are similar to the operations of steps 710 to 720 described above, and are not described again here.

According to an embodiment of the present disclosure, as shown in fig. 12, there is also provided a noise removing apparatus 1200 of a quantum measurement device, including: a second obtaining unit 1210 configured to obtain a quantum state ρ of n qubits to be measured, where n is a positive integer; a second determining unit 1220, configured to determine a measurement result corresponding to the quantum state ρ after quantum noise of the quantum measurement device is eliminated; the third obtaining unit 1230 is configured to obtain a measurement result corresponding to the quantum state ρ after the classical noise is removed, based on a quantum measurement device calibration method and the measurement result. The method according to any one of the above embodiments determines the measurement result corresponding to the quantum state ρ after eliminating the quantum noise of the quantum measurement device.

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

Referring to fig. 13, a block diagram of a structure of an electronic device 1300, which 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 device is 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 phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the disclosure described and/or claimed herein.

As shown in fig. 13, the electronic device 1300 includes a computing unit 1301 that can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM)1302 or a computer program loaded from a storage unit 1308 into a Random Access Memory (RAM) 1303. In the RAM 1303, various programs and data necessary for the operation of the electronic device 1300 can also be stored. The calculation unit 1301, the ROM 1302, and the RAM 1303 are connected to each other via a bus 1304. An input/output (I/O) interface 1305 is also connected to bus 1304.

A number of components in the electronic device 1300 are connected to the I/O interface 1305, including: input section 1306, output section 1307, storage section 1308, and communication section 1309. The input unit 1306 may be any type of device capable of inputting information to the electronic device 1300, and the input unit 1306 may receive input numeric or character information and generate key signal inputs related to user settings and/or function controls of the electronic device, and may include, but is not limited to, a mouse, a keyboard, a touch screen, a track pad, a track ball, a joystick, a microphone, and/or a remote controller. Output unit 1307 can be any type of device capable of presenting information and can include, but is not limited to, a display, speakers, a video/audio output terminal, a vibrator, and/or a printer. Storage unit 1308 can include, but is not limited to, a magnetic disk, an optical disk. The communication unit 1309 allows the electronic device 1300 to exchange information/data with other devices via a computer network, such as the internet, and/or various telecommunications networks, and may include, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication transceiver, and/or a chipset, such as a bluetooth (TM) device, an 802.11 device, a WiFi device, a WiMax device, a cellular communication device, and/or the like.

Computing unit 1301 may be a variety of general and/or special purpose processing components with processing and computing capabilities. Some examples of computing unit 1301 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, and so forth. The computing unit 1301 performs the various methods and processes described above, such as the method 700. For example, in some embodiments, method 700 may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as storage unit 1308. In some embodiments, part or all of the computer program can be loaded and/or installed onto the electronic device 1300 via the ROM 1302 and/or the communication unit 1309. When loaded into RAM 1303 and executed by computing unit 1301, a computer program may perform one or more of the steps of method 700 described above. Alternatively, in other embodiments, computing unit 1301 may be configured in any other suitable manner (e.g., by way of firmware) to perform method 700.

Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuitry, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Application Specific Standard Products (ASSPs), system on a 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 that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, receiving data and instructions from, and transmitting data and instructions to, a storage system, at least one input device, and at least one output device.

Program code for implementing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes 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 codes, when executed by the processor or controller, cause the functions/operations specified in the flowchart and/or block diagram to be performed. 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. A 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 a pointing device (e.g., a mouse or a 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 can 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, speech, or tactile input.

The systems and techniques described here can be implemented in a computing system that includes a back-end 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 back-end, 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 clients and servers. A client and server are generally 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 with a combined blockchain.

It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present disclosure may be performed in parallel, sequentially or in different orders, and are not limited herein as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved.

Although embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it is to be understood that the above-described 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 as issued and their equivalents. Various elements in the embodiments or examples may be omitted or may be replaced with equivalents thereof. Further, the steps may be performed in an order different from that described in the present disclosure. Further, various elements in 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 with equivalent elements that appear after the present disclosure.

Claims

1. A quantum noise cancellation method of a quantum measurement device, comprising:

performing a first operation for a first preset number of times to determine an average probability value of occurrence of each of at least one measurement result as a measurement result obtained after quantum noise is removed,

wherein the first operation comprises the steps of:

obtaining quantum state rho of n quantum bits to be measured, wherein n is a positive integer;

randomly selecting n times in a Paly gate set { single-bit Pay X gate, single-bit Pay Y gate } to obtain n Pay gates;

respectively acting the n Pauli gates on each quantum bit of the quantum state rho to obtain an acted quantum state;

repeatedly operating the quantum measurement equipment to measure the acted quantum state for a second preset number of times, and turning the state of each bit of the obtained measurement result in the form of a binary character string; and

and counting the measurement results after the state is turned over to determine the probability value of each occurrence of the at least one measurement result.

2. The method of claim 1, wherein the first predetermined number of times is not less than 2 ⁿ 。

3. A noise cancellation method of a quantum measurement apparatus, comprising:

determining a measurement result corresponding to the quantum state rho after quantum noise of the quantum measurement equipment is eliminated;

obtaining a measurement result corresponding to the quantum state rho after classical noise elimination based on a quantum measurement device calibration method and the measurement result,

wherein the method according to any of claims 1-2 determines the measurement result corresponding to the quantum state p after eliminating the quantum noise of the quantum measurement device.

4. A quantum noise cancellation device of a quantum measurement apparatus, comprising:

a first determination unit configured to perform a first operation a first preset number of times to determine an average probability value of respective occurrences of at least one measurement result as a measurement result obtained after quantum noise is removed,

wherein the first operation comprises the steps of:

5. The apparatus of claim 4, wherein the first predetermined number of times is not less than 2 ⁿ 。

6. A noise cancellation device of a quantum measuring apparatus, comprising:

a first acquisition unit configured to acquire a quantum state ρ of n qubits to be measured, where n is a positive integer;

a second determination unit configured to determine a measurement result corresponding to the quantum state ρ after quantum noise of the quantum measurement device is eliminated;

a second obtaining unit configured to obtain a measurement result corresponding to the quantum state ρ after removal of classical noise based on a quantum measurement apparatus calibration method and the measurement result,

the method according to any one of claims 1-2, wherein the measurement result corresponding to the quantum state p after eliminating quantum noise of the quantum measurement device is determined.

7. An electronic device, comprising:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein

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 1-3.

8. A non-transitory computer readable storage medium having stored thereon computer instructions for causing the computer to perform the method of any one of claims 1-3.

9. A computer program product comprising a computer program, wherein the computer program realizes the method of any one of claims 1-3 when executed by a processor.