Quantum device performance verification method and device, electronic device and medium

Abstract

The present disclosure provides a method, apparatus, electronic device, computer-readable storage medium and computer program product for verifying the performance of a quantum device, which relates to the field of quantum computers, and in particular to the field of quantum local verification technology. The implementation scheme is: performing a first operation: generating a two-bit quantum state shared by a first and a second quantum system through a quantum device; randomly selecting a scheme from a plurality of preset verification schemes to measure the two-bit quantum state. The plurality of verification schemes include: performing an X measurement among the X, Y, and Z measurements on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; performing a Y measurement among the X, Y, and Z measurements on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and performing a Z measurement among the X, Y, and Z measurements on both the first quantum system and the second quantum system.

Description

Technical Field

[0001] The present disclosure relates to the field of quantum computers, in particular to the field of quantum local verification technology, and specifically to a quantum device performance verification method, apparatus, electronic device, computer-readable storage medium, and computer program product. Background Art

[0002] Quantum entanglement has very important applications in the fields of quantum computing and quantum information processing. Inaccurate quantum entangled states will significantly affect the results of quantum computing and quantum information processing. Therefore, before using quantum devices to generate entangled states, it is necessary to complete quantum device performance verification to ensure the quality of entanglement. Performance verification of quantum devices requires a large number of repeated experiments to reduce the probability of false assertions. The more experiments are conducted, the more time and quantum state resources are consumed. Summary of the invention

[0003] The present disclosure provides a quantum device performance verification method, apparatus, electronic device, computer-readable storage medium, and computer program product.

[0004] According to one aspect of the present disclosure, a method for verifying the performance of a quantum device is provided, comprising: performing a first operation, wherein the first operation comprises the following steps: generating, by the quantum device, a two-bit quantum state shared by a first quantum system and a second quantum system; randomly selecting a scheme from a plurality of preset verification schemes to measure the two-bit quantum state to obtain a corresponding measurement result; in response to determining that the measurement results on the first quantum system and the second quantum system both meet the expected results and the number of executions of the first operation does not exceed a preset number of times, repeatedly performing the first operation; and in response to the measurement results obtained after performing the first operation a preset number of times both meet the expected results, determining that the quantum device is capable of generating a two-bit quantum state that meets the requirements, wherein the plurality of verification schemes comprise: a first verification scheme: performing an X measurement in a Pauli X, Y, Z measurement on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; a second verification scheme: performing a Y measurement in a Pauli X, Y, Z measurement on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and a third verification scheme: performing a Z measurement in a Pauli X, Y, Z measurement on both the first quantum system and the second quantum system.

[0005] According to another aspect of the present disclosure, a quantum device performance verification apparatus is provided, comprising: an execution unit configured to execute a first operation, wherein the first operation comprises the following steps: generating, by the quantum device, a two-bit quantum state shared by a first quantum system and a second quantum system; randomly selecting a scheme from a plurality of preset verification schemes to measure the two-bit quantum state to obtain a corresponding measurement result; a first determination unit configured to, in response to determining that the measurement results on the first quantum system and the second quantum system are both consistent with expected results and the number of executions of the first operation does not exceed a preset number of times, repeatedly execute the first operation; and a second determination unit configured to, in response to determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results and the number of executions of the first operation does not exceed a preset number of times, repeatedly execute the first operation; The obtained measurement results all meet the expected results, and it is determined that the quantum device can generate a two-bit quantum state that meets the requirements, wherein the multiple verification schemes include: a first verification scheme: performing an X measurement in the Pauli X, Y, Z measurement on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; a second verification scheme: performing a Y measurement in the Pauli X, Y, Z measurement on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and a third verification scheme: performing a Z measurement in the Pauli X, Y, Z measurement on both the first quantum system and the second quantum system.

[0006] According to another aspect of the present disclosure, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the method described in the present disclosure.

[0007] According to another aspect of the present disclosure, a non-transitory computer-readable storage medium storing computer instructions is provided. The computer instructions are used to cause a computer to execute the method described in the present disclosure.

[0008] According to another aspect of the present disclosure, a computer program product is provided, including a computer program, which implements the method described in the present disclosure when executed by a processor.

[0009] According to one or more embodiments of the present disclosure, when verifying the performance of a quantum device that generates a two-bit quantum state through local measurement, fewer different measurement configurations may be required, thereby having greater operability.

[0010] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings exemplarily illustrate the embodiments and constitute a part of the specification, and together with the text description of the specification, are used to explain the exemplary implementation of the embodiments. The embodiments shown are for illustrative purposes only and do not limit the scope of the claims. In all drawings, the same reference numerals refer to similar but not necessarily identical elements.

[0012] Figure 1 A schematic diagram of LOCC-based quantum device performance verification according to an embodiment of the present disclosure is shown;

[0013] Figure 2 A flowchart of a method for verifying quantum device performance according to an embodiment of the present disclosure is shown;

[0014] Figure 3 A block diagram showing a structure of a quantum device performance verification apparatus according to an embodiment of the present disclosure; and

[0015] Figure 4 A structural block diagram of an exemplary electronic device that can be used to implement the embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0016] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present disclosure. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0017] 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, timing relationship, or importance relationship of these elements, and such terms are only used to distinguish one element from another element. In some examples, the first element and the second element may refer to the same instance of the element, and in some cases, based on the description of the context, they may also refer to different instances.

[0018] The terms used in the description of various examples in this disclosure are only for the purpose of describing specific examples and are not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element can be one or more. In addition, the term "and / or" used in this disclosure covers any one of the listed items and all possible combinations.

[0019] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0020] So far, all the different types of computers in use are based on classical physics as the theoretical basis for information processing, and are called traditional computers or classical computers. Classical information systems use binary data bits, which are the easiest to implement physically, to store data or programs. Each binary data bit is represented by 0 or 1, called a bit or bit, as the smallest unit of information. Classical computers themselves have inevitable weaknesses: one is the most basic limitation of energy consumption in the computing process. The minimum energy required for logic elements or storage units should be several times more than kT to avoid misoperation due to thermal expansion and fall; the second is information entropy and heat energy consumption; the third is that when the wiring density of computer chips is very high, according to the Heisenberg uncertainty relation, when the uncertainty of the electron position is very small, the uncertainty of the momentum will be very large. Electrons are no longer bound, and there will be quantum interference effects, which may even destroy the performance of the chip.

[0021] A quantum computer is a physical device that follows the properties and laws of quantum mechanics to perform high-speed mathematical and logical operations, store and process quantum information. When a device processes and calculates quantum information and runs quantum algorithms, it is a quantum computer. Quantum computers follow the unique laws of quantum dynamics (especially quantum interference) to achieve a new mode of information processing. For parallel processing of computational problems, quantum computers have an absolute advantage in speed over classical computers. The transformation of each superposition component by a quantum computer is equivalent to a classical calculation. All these classical calculations are completed at the same time and superimposed according to a certain probability amplitude to give the output result of the quantum computer. This calculation is called quantum parallel computing. Quantum parallel processing greatly improves the efficiency of quantum computers, allowing them to complete tasks that classical computers cannot complete, such as factoring a large natural number. Quantum coherence is essentially used in all quantum ultra-fast algorithms. Therefore, quantum parallel computing, which replaces classical states with quantum states, can achieve computing speeds and information processing functions that are incomparable to classical computers, while saving a lot of computing resources.

[0022] Quantum computing based on quantum computers is the core of the next generation of computing technology. More and more emerging quantum technologies are emerging, the technology of quantum hardware is improving year by year, and quantum communication and quantum Internet are also developing. One of the most important resources of quantum technology is quantum entanglement, which is the core resource and basic component of quantum computing and quantum information processing. It is the core part of many famous quantum information processing cases, such as quantum key distribution, quantum superdense coding, and quantum teleportation.

[0023] Taking quantum super-dense coding as an example, the relevant quantum protocol is as follows: Alice and Bob, the two parties in the protocol communication, pre-share a pair of highly entangled Bell states; Alice performs corresponding quantum coding operations on the quantum bits she holds according to the two bits of classical information that need to be transmitted, and then transmits the quantum bit after the operation to Bob through an ideal quantum channel; Bob performs Bell measurement on the received quantum bits and the quantum bits originally held, and decodes the two bits of classical information transmitted by Alice. Quantum super-dense coding cleverly uses the properties of quantum entanglement to transmit two classical bits of information through one quantum bit, thereby achieving a communication method with greater capacity and higher efficiency.

[0024] In quantum super-dense coding, Alice and Bob need to share a pair of highly entangled Bell quantum states to encode the transmitted classical information. If the fidelity of the Bell states they share is not high enough, the super-dense coding protocol cannot be carried out normally, and Bob cannot accurately decode the classical information transmitted by Alice, which cannot reflect the advantages of quantum information processing.

[0025] It can be seen from the quantum super-dense coding protocol that how to efficiently verify whether an unknown quantum device accurately produces the target quantum state (Bell quantum state in the quantum super-dense coding protocol) is a core issue in quantum computing. In addition, considering that the verification process itself cannot consume more and more stringent resources than the object to be verified (target quantum state), the two parties involved in the verification are required to use only local quantum operations and classical communication (Local Operations and Classical Communication, LOCC) to complete the verification process through classical data post-processing.

[0026] When a two-bit quantum state is locally verified by a local quantum operation, for example, a device manufacturer builds a quantum device Theoretically, this quantum device can create a two-bit entangled quantum state |Ψ θ >:

[0027] |Ψ θ >:=sinθ|00>+cosθ|11>

[0028] Among them, θ∈[0,π / 2] is given by the equipment manufacturer. When θ=π / 4, the entangled state above corresponds to the Bell state. Each call to the quantum device A two-bit quantum state σ can be generated at one time AB (This quantum state belongs to the two quantum systems Alice and Bob).

[0029] The device manufacturer can ensure that the quantum device must fall into one of the following two situations: Good Case - Quantum Device Capable of precisely manufacturing quantum states |Ψ θ >, that is, F(σ AB ,Ψ θ ):=<Ψ θ |σ|Ψ θ >=1, where Ψ θ ≡|Ψ θ ><Ψ θ |; or, Bad Case – Quantum Devices The quantum state σ AB and |Ψ θ > has a fidelity less than or equal to 1-ε, that is, F(σ AB ,Ψ θ ):=<Ψ θ |σ AB |Ψ θ >≤1-ε, where ε is the error value preset by the manufacturer and F() represents the fidelity function. Alice and Bob are using quantum devices Before that, we first need to determine the quantum device Which case is it: If it is a GoodCase, then the quantum state generated by the quantum device can be used θ > to perform quantum information processing tasks; if it is a BadCase, the quantum device cannot be used to perform quantum information processing tasks. Figure 1 A schematic diagram of LOCC-based quantum device performance verification according to an embodiment of the present disclosure is shown.

[0030] Considering the limited quantum capabilities of Alice and Bob, as mentioned above, local verification can be used to verify their quantum performance. Specifically, calling the quantum device Generate a quantum state σ AB , subscript A indicates that the first qubit is located in Alice's quantum system, and subscript B indicates that the second qubit is located in Bob's quantum system. Alice and Bob use local measurements to measure the two qubits respectively and record the measurement results. They then transmit the measurement results through classical communication and determine whether the quantum device belongs to a good case or a bad case.

[0031] Given a performance verification scheme, two indicators can generally be used to evaluate the performance of the scheme: 1) The number of times the quantum device is called, that is, the total number of unknown quantum states that the verification scheme needs to prepare. The fewer the total number of times, the fewer times Alice and Bob need to repeat the verification, which is more efficient in the experiment. 2) The number of different measurement configurations. Generally speaking, the verification scheme will randomly select a measurement scheme in each round, which is called a measurement setting. The fewer the number of different measurement configurations, the fewer different local measurements Alice and Bob need to implement, so it is more advantageous in the experiment. However, most quantum state verification schemes only achieve the optimal number of times the quantum device is called, but ignore whether the number of different measurement configurations can achieve the optimal number.

[0032] Therefore, according to an embodiment of the present disclosure, a method for verifying the performance of a quantum device is provided. Figure 2 FIG. 1 is a flow chart of a method for verifying quantum device performance according to an embodiment of the present disclosure. Figure 2 As shown, method 200 includes: performing a first operation (step 210); in response to determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results and the number of executions of the first operation does not exceed a preset number of times, repeatedly performing the first operation (step 220); and in response to the measurement results obtained after performing the first operation a preset number of times are consistent with the expected results, determining that the quantum device can generate a two-bit quantum state that meets the requirements (step 230).

[0033] In an embodiment of the present disclosure, the first operation includes the following steps: generating a two-bit quantum state shared by a first quantum system and a second quantum system through the quantum device; randomly selecting a scheme from a plurality of preset verification schemes to measure the two-bit quantum state to obtain a corresponding measurement result. In addition, the plurality of verification schemes include: a first verification scheme: performing an X measurement in the Pauli X, Y, Z measurement on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; a second verification scheme: performing a Y measurement in the Pauli X, Y, Z measurement on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and a third verification scheme: performing a Z measurement in the Pauli X, Y, Z measurement on both the first quantum system and the second quantum system.

[0034] In an embodiment according to the present disclosure, when the performance of a quantum device that generates a two-bit quantum state is verified through local measurement, fewer different measurement configurations may be required, thereby having stronger operability.

[0035] According to some embodiments, the further step further includes: in response to measurement results on the first quantum system and the second quantum system not meeting expected results, determining that the quantum device is unable to generate a meeting-required two-bit quantum state.

[0036] In order to accurately determine whether an unknown quantum device produces the target quantum state |Ψ θ >, the verification strategy of Alice and Bob (first quantum system and second quantum system) can satisfy the following constraints: 1) If the unknown quantum device does make |Ψ θ >, Alice and Bob always assert Good Case to prevent accidental injury, if the unknown quantum device does not make |Ψ θ >, the smaller the probability that Alice and Bob incorrectly assert a Good Case, the better; 2) the quantum measurements used by Alice and Bob are local measurements rather than entangled measurements; 3) Alice and Bob use random quantum measurements, so that equipment manufacturers cannot customize erroneous quantum states that always pass the test based on the deterministic measurement information used by Alice and Bob, thereby deceiving Alice and Bob.

[0037] For example, Alice and Bob use a single-bit standard basis measurement {|0><0|, {|1><1|} for verification. θ >The output of these two local measurements is always 00 or 11, so if the unknown quantum device After making a measurement and the output is one of these two outputs, Alice and Bob can assert that the unknown quantum device is a GoodCase; conversely, if a measurement result is 01 or 10, it can be asserted that the unknown quantum device It is a Bad Case.

[0038] In general, the performance of two-bit quantum states generated by unknown quantum devices can be verified using an optimal global verification scheme. The optimal global verification scheme requires the use of special entanglement measurements. First, four two-bit quantum states are defined:

[0039]

[0040]

[0041]

[0042]

[0043] It should be noted that This is the target quantum state to be verified mentioned above |Ψ θ > (i.e. two-bit entangled quantum state). Based on these four quantum states, the following form of entanglement measurement is defined:

[0044]

[0045] Among them, θ∈[0,π / 2], The subscript i in represents the corresponding output result, that is, there are four output results of the measurement, namely 0, 1, 2, and 3. Note that the corresponding results in binary representation are 00, 01, 10, and 11. In particular, when θ = π / 4, the entanglement measurement is Bell Measurement.

[0046] For example, in the optimal global verification scheme, the following operations may be included:

[0047] Step 1: Get the total number of test rounds N that need to be executed g , and initialize the iteration parameter k=0.

[0048] Step 2: Update the iteration parameter k=k+1 and make the following judgment:

[0049] If k < N g , execute step 3 (i.e., perform entanglement measurement and continue testing the unknown quantum device).

[0050] If k ≥ N g , jump to step 4 (i.e. the verification process is completed and the quantum device passes the test);

[0051] Step 3: Alice and Bob call the quantum device Generate a two-bit quantum state σ and use entanglement measurement Measure the quantum state. If the measurement result is 0, jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0052] Step 4: Output Good Case.

[0053] It can be understood that the number of quantum devices required to call the optimal global verification scheme can be determined according to the following formula:

[0054]

[0055] Among them, ε is the error tolerance of the preset quantum device, and δ is the confidence level of the preset error in verifying the performance of the quantum device. At the same time, it can be seen that the number of measurement configurations required for the optimal global verification scheme is 1 (that is, only the entanglement measurement is required). ).

[0056] However, when locally verifying a two-bit quantum state through a local quantum operation, the usual verification scheme may include the following steps:

[0057] Step 1: Get the total number of test rounds N that need to be executed l, and initialize the iteration parameter k=0.

[0058] Step 2: Update the iteration parameter k=k+1 and make the following judgment:

[0059] If k < N l , execute step 3 (i.e., perform local measurement and continue testing the unknown quantum device).

[0060] If k ≥ N l , jump to step 5 (i.e. the verification process is completed and the quantum device passes the test);

[0061] Step 3: Alice and Bob randomly determine which party will perform the local measurement first in this round through classical communication (that is, each party has a 1 / 2 probability of performing the measurement first), and the local measurement that the other party needs to perform depends on the measurement result of the party that performs the measurement first. The following steps assume that Alice has been determined to perform the measurement first (if Bob performs the measurement first, just swap the identities of the two).

[0062] Step 4: Alice and Bob call the device Generate a two-bit quantum state σ and measure σ using a uniformly random selection of the following three local measurement schemes:

[0063] 1) Alice performs the Pauli X measurement and sends the single-bit measurement result to Bob:

[0064] If Alice's measurement result is 0 (corresponding to a positive eigenvector of X's measurement), Bob executes {|v + > <v + |,I-|v + > <v + |} measurement, where |v + >=sinθ|0>+cosθ|1>. If Bob's measurement result is v + , then jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0065] If Alice's measurement result is 1 (corresponding to the negative eigenvector of X's measurement), Bob executes {|v - > <v - |,I-|v - > <v - |} measurement, where |v - >=sinθ|0>-cosθ|1>. If Bob's measurement result is v _ , then jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0066] 2) Alice performs the Pauli Y measurement and sends the single-bit measurement result to Bob:

[0067] If Alice's measurement result is 0 (corresponding to a positive eigenvector of the Y measurement), Bob executes {|w - > <w - |,I-|w - > <w - |} measurement, where |w - >=sinθ|0>-icosθ|1>. If Bob's measurement result is w - , then jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0068] If Alice's measurement result is 1 (corresponding to the negative eigenvector of Y measurement), Bob executes {|w + > <w + |,I-|w + > <w + |} measurement, where |w + >=sinθ|0>+i cosθ|1>. If Bob's measurement result is w + , then jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0069] 3) Alice and Bob perform Pauli Z measurement respectively. If the measurement result is 00 or 11, jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0070] Step 5: Output Good Case.

[0071] It can be understood that the number of quantum devices required to be called for the above local verification scheme is:

[0072]

[0073] By comparison, the above local verification scheme has a coefficient of In addition, by analyzing the expansion steps of the scheme, it can be seen that the number of different measurement configurations required by the above local verification scheme is 9, as shown in Table 1.

[0074] counter Alice measures Bob Measurement 1 X <![CDATA[{|v + > <v + |,I-|v + > <v + |}]]> 2 X <![CDATA[{|v - > <v - |,I-|v - > <v - |}]]> 3 Y <![CDATA[{|w - > <w - |,I-|in - > <w - |}]]> 4 Y <![CDATA[{|w + > <w + |,I-|in + > <w + |}]]> 5 Z Z 6 <![CDATA[{|v + > <v + |,I-|v + > <v + |}]]> X 7 <![CDATA[{|v - > <v - |,I-|v - > <v - |}]]> X 8 <![CDATA[{|w - > <w - |,I-|in - > <w - |}]]> Y 9 <![CDATA[{|w + > <w + |,I-|in + > <w + |}]]> Y

[0075] Table 1

[0076] It can be seen from the above embodiments that the optimal global verification scheme can achieve the optimal number of times the quantum device is called and the number of different measurement configurations at the same time, but it requires the verifier (Alice and Bob) to implement entangled measurement. If Alice and Bob are far apart, entangled measurement cannot be achieved. The above-mentioned local verification scheme uses local measurement, which can be efficiently implemented even when Alice and Bob are far apart, but the efficiency of this scheme requires up to 9 different measurement configurations. For Alice and Bob, who have limited quantum capabilities, it may be difficult to implement so many different local measurements.

[0077] Through further analysis, it is found that in step 4 of the above local verification scheme, Alice and Bob can randomly decide which party will perform the local measurement first. This actually takes advantage of the permutation invariant property of the target quantum state, that is, the exchange of roles between Alice and Bob does not affect the correctness of the verification process. However, it is precisely because of this interchangeability that both parties are forced to perform the same measurement configuration, even if this measurement configuration is not necessary, which leads to redundant measurement configuration.

[0078] Therefore, in the embodiment according to the present disclosure, the exchange invariance property is no longer simply used to interchange the identity roles of Alice and Bob (i.e., the first quantum system and the second quantum system). Instead, the appropriate measurement configuration is selected in combination with the specific form of the target quantum state, thereby eliminating information redundancy.

[0079] Specifically, according to some embodiments, when the first measurement result is 0, the measurement operation corresponding to the first measurement result is {|v + > <v + |,I-|v + > <v + |} measurement operation, where |v + >=sinθ|0>+cosθ|1>;When the first measurement result is 1, the measurement operation corresponding to the first measurement result is {|v - > <v - |,I-|v - > <v - |} measurement operation, where |v - >=sinθ|0>-cosθ|1>.

[0080] According to some embodiments, determining that the measurement results on the first quantum system and the second quantum system both meet the expected results includes: when selecting the first verification scheme to perform the two-bit quantum state measurement, in response to determining that the corresponding measurement result on the first quantum system is 0 and the corresponding measurement result on the second quantum system is v+ , determining that the measurement results on the first quantum system and the second quantum system are consistent with the expected results; in response to determining that the corresponding measurement result on the first quantum system is 1, and the corresponding measurement result on the second quantum system is v - , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results.

[0081] According to some embodiments, when the second measurement result is 0, the measurement operation corresponding to the second measurement result is {|w - > <w - |,I-|w - > <w - |} measurement operation, where |w - >=sinθ|0>-icosθ|1>;When the second measurement result is 1, the measurement operation corresponding to the first measurement result is {|w + > <w + |,I-|w + > <w + |} measurement operation, where |w + >=sinθ|0>+icosθ|1>.

[0082] According to some embodiments, determining that the measurement results on the first quantum system and the second quantum system both meet the expected results includes: when selecting the second verification scheme to perform the two-bit quantum state measurement, in response to determining that the corresponding measurement result on the second quantum system is 0 and the corresponding measurement result on the first quantum system is w - , determining that the measurement results on the first quantum system and the second quantum system are consistent with the expected results; in response to determining that the corresponding measurement result on the second quantum system is 1, and the corresponding measurement result on the first quantum system is w + , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results.

[0083] According to some embodiments, determining that the measurement results on the first quantum system and the second quantum system both meet expected results includes: when selecting the third verification scheme to perform the two-bit quantum state measurement, in response to determining that the corresponding measurement result on the first quantum system is 00 or 11, and the measurement result on the second quantum system is 00 or 11, determining that the measurement results on the first quantum system and the second quantum system both meet expected results.

[0084] It can be seen that in the process of selecting a suitable measurement configuration in combination with the specific form of the target quantum state, the number of different measurement configurations required by the local verification scheme according to the embodiment of the present disclosure is 5, as shown in Table 2 (where Alice is taken as the first quantum system as an example).

[0085] counter Alice measures Bob Measurement 1 X <![CDATA[{|v + > <v + |,I-|v + > <v + |}]]> 2 X <![CDATA[{|v - > <v - |,I-|v - > <v - |}]]> 3 Z Z 4 <![CDATA[{|w - > <w - |,I-|in - > <w - |}]]> Y 5 <![CDATA[{|w + > <w + |,I-|in + > <w + |}]]> Y

[0086] Table 2

[0087] According to some embodiments, the preset number N o Determined based on the following formula:

[0088]

[0089] Among them, ε is the preset error tolerance of the quantum device, and δ is the preset confidence level of errors in verifying the performance of the quantum device.

[0090] Thus, in this embodiment, there is only an additional cost of a factor of 3 / 2 relative to the optimal global verification scheme, which is consistent with the performance of the local verification scheme described above. However, at this time, the number of different measurement configurations required by Alice and Bob is 5, which has a clear advantage.

[0091] In an exemplary embodiment according to the present disclosure, the unknown quantum device generating the two-bit quantum state can be locally verified by the following steps:

[0092] Step 1: Calculate the total number of testing rounds that need to be performed Initialize the iteration parameter k=0.

[0093] Step 2: Update the iteration parameter k=k+1 and make the following judgment:

[0094] If k < N o , execute step 3 (i.e., perform local measurement and continue testing the unknown quantum device).

[0095] If k ≥ N o , jump to step 4 (i.e. the verification process is completed and the quantum device passes the test);

[0096] Step 3: Alice and Bob call the quantum device to generate a two-bit quantum state σ, and uniformly and randomly select a measurement scheme from the following three local measurement schemes to measure σ (the following steps assume that Alice is the first quantum system. If Bob is the first quantum system, just swap the identities of the two):

[0097] 1) Alice performs X measurement and sends the single-bit measurement result to Bob:

[0098] If Alice's measurement result is 0 (corresponding to a positive eigenvector of X's measurement), Bob executes {|v + > <v + |,I-|v + > <v + |} measurement, where |v + >=sinθ|0>+cosθ|1>. If Bob's measurement result is v + , then jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0099] If Alice's measurement result is 1 (corresponding to the negative eigenvector of X's measurement), Bob executes {|v - > <v - |,I-|v - > <v - |} measurement, where |v - >=sinθ|0>-coSθ|1>. If Bob's measurement result is v - , then jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0100] 2) Bob performs the Pauli Y measurement and sends the single-bit measurement result to Alice:

[0101] If Bob's measurement result is 0 (corresponding to a positive eigenvector of the Y measurement), Alice executes {|w - > <w - |,I-|w - > <w - |} measurement, where |w - >=sinθ|0>-icosθ|1>. If Alice's measurement result is w - , then jump to step 2 for the next round of testing; otherwise, directly output BadCase.

[0102] If Bob's measurement result is 1 (corresponding to the negative eigenvector of Y measurement), Alice executes {|w + > <w + |,I-|w + > <w + |} measurement, where |w + >=sinθ|0>+i cosθ|1>. If Alice's measurement result is w + , then jump to step 2 for the next round of testing; otherwise, directly output BadCase.

[0103] 3) Alice and Bob perform Pauli Z measurement respectively. If the measurement result is 00 or 11, jump to step 2 for the next round of testing; otherwise, directly output Bad Case.

[0104] Step 4: Output Good Case.

[0105] Therefore, if the steps executed in the above embodiment finally output a Bad Case, it can be believed that the quantum device is not |Ψ θ >. If the final output is Good Case, then there is a probability of more than 1-δ that the quantum device produced |Ψ θ >.

[0106] According to the scheme of the embodiment of the present disclosure, when the performance of a quantum device that generates a two-bit quantum state is verified through local measurement, the two indicators of the number of times the quantum device is called and the number of different measurement configurations can be optimized at the same time, which has strong practicality and can be widely used in small and medium-scale quantum devices integrating hundreds of physical quantum bits, and can efficiently verify whether an unknown quantum device accurately generates the target quantum state |Ψ θ >, and then use these devices to realize more valuable applications and accelerate the progress of the Noisy Intermediate-Scale Quantum (NISQ) era.

[0107] According to the embodiments of the present disclosure, Figure 3 As shown, a quantum device performance verification apparatus 300 is also provided, including: an execution unit 310, configured to execute a first operation, wherein the first operation includes the following steps: generating a two-bit quantum state shared by a first quantum system and a second quantum system through the quantum device; randomly selecting a scheme from a plurality of preset verification schemes to measure the two-bit quantum state to obtain a corresponding measurement result; a first determination unit 320, configured to, in response to determining that the measurement results on the first quantum system and the second quantum system both meet the expected results and the number of executions of the first operation does not exceed the preset number of times, repeatedly execute the first operation; and a second determination unit 330, configured to, in response to the measurement results obtained after executing the first operation a preset number of times all meet the expected results, determine that the quantum device can generate a two-bit quantum state that meets the requirements.

[0108] In an embodiment of the present disclosure, the multiple verification schemes include: a first verification scheme: performing an X measurement in the Pauli X, Y, Z measurement on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; a second verification scheme: performing a Y measurement in the Pauli X, Y, Z measurement on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and a third verification scheme: performing a Z measurement in the Pauli X, Y, Z measurement on both the first quantum system and the second quantum system.

[0109] Here, the operations of the above-mentioned units 310-330 of the quantum device performance verification apparatus 300 are similar to the operations of steps 210-230 described above, and will not be repeated here.

[0110] According to an embodiment of the present disclosure, an electronic device, a readable storage medium and a computer program product are also provided.

[0111] refer to Figure 4 , a block diagram of an electronic device 400 that can be used as a server or client of the present disclosure will now be described, which is an example of a hardware device that can be applied to various aspects of the present disclosure. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can 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 merely examples and are not intended to limit the implementation of the present disclosure described and / or required herein.

[0112] like Figure 4 As shown, the electronic device 400 includes a computing unit 401, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 402 or a computer program loaded from a storage unit 408 into a random access memory (RAM) 403. In the RAM 403, various programs and data required for the operation of the electronic device 400 can also be stored. The computing unit 401, the ROM 402, and the RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0113] Multiple components in the electronic device 400 are connected to the I / O interface 405, including: an input unit 406, an output unit 407, a storage unit 408, and a communication unit 409. The input unit 406 can be any type of device that can input information to the electronic device 400. The input unit 406 can receive input digital or character information and generate key signal input related to user settings and / or function control of the electronic device, and can 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. The output unit 407 can be any type of device that can present information, and can include but is not limited to a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 408 can include but is not limited to a disk, an optical disk. The communication unit 409 allows the electronic device 400 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can 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 device, an 802.11 device, a WiFi device, a WiMax device, a cellular communication device, and / or the like.

[0114] The computing unit 401 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 401 performs the various methods and processes described above, such as method 200. For example, in some embodiments, the method 200 may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 408. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 400 via ROM 402 and / or communication unit 409. When the computer program is loaded into RAM 403 and executed by the computing unit 401, one or more steps of the method 200 described above may be performed. Alternatively, in other embodiments, the computing unit 401 may be configured to perform the method 200 in any other appropriate manner (e.g., by means of firmware).

[0115] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0116] The program code for implementing the method 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, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0117] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A 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, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, 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 disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0118] To provide interaction with a user, the systems and techniques described herein 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 the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the 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 can be received in any form (including acoustic input, voice input, or tactile input).

[0119] The systems and techniques described herein can be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend 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: a local area network (LAN), a wide area network (WAN), the Internet, and a blockchain network.

[0120] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0121] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in this disclosure can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this document does not limit this.

[0122] Although the embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above-mentioned methods, systems and devices are merely exemplary embodiments or examples, and the scope of the present invention is not limited by these embodiments or examples, but only by the claims after authorization and their equivalent scope. Various elements in the embodiments or examples can be omitted or replaced by their equivalent elements. In addition, each step can be performed in an order different from that described in the present disclosure. Further, the various elements in the embodiments or examples can be combined in various ways. It is important that with the evolution of technology, many elements described herein can be replaced by equivalent elements that appear after the present disclosure.

Claims

1. A method for verifying quantum device performance, comprising: Perform a first operation, wherein the first operation includes the following steps: generating, by the quantum device, a two-bit quantum state shared by a first quantum system and a second quantum system; Randomly select a scheme from a plurality of preset verification schemes to measure the two-bit quantum state to obtain a corresponding measurement result; In response to determining that the measurement results on the first quantum system and the second quantum system both meet expected results and the number of executions of the first operation does not exceed a preset number, repeatedly executing the first operation; and In response to the measurement results obtained after performing the first operation for a preset number of times all meeting the expected results, it is determined that the quantum device is capable of generating a two-bit quantum state that meets the requirements, wherein: The multiple verification schemes include: First verification scheme: performing an X measurement in the Pauli X, Y, Z measurement on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; A second verification scheme: performing a Y measurement in the Pauli X, Y, Z measurement on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and A third verification scheme: performing Z measurement in the Pauli X, Y, Z measurement on both the first quantum system and the second quantum system.

2. The method of claim 1, further comprising: In response to measurement results on the first quantum system and the second quantum system not meeting expected results, it is determined that the quantum device is unable to generate a satisfactory two-bit quantum state.

3. The method of claim 1, wherein: When the first measurement result is 0, the measurement operation corresponding to the first measurement result is {|v + > <v + |,I-|v + > <v + |} measurement operation, where |v + >=sinθ|0>+cosθ|1>; When the first measurement result is 1, the measurement operation corresponding to the first measurement result is {|v - > <v - |,I-|v - > <v - |} measurement operation, where |v - >=sinθ|0>-cosθ|1>.

4. The method of claim 3, wherein: Determining that the measurement results on the first quantum system and the second quantum system are consistent with the expected results includes: when selecting the first verification scheme to perform the two-bit quantum state measurement, In response to determining that the corresponding measurement result on the first quantum system is 0 and the corresponding measurement result on the second quantum system is v + , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results; In response to determining that the corresponding measurement result on the first quantum system is 1, and the corresponding measurement result on the second quantum system is v - , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results.

5. The method of claim 1, wherein: When the second measurement result is 0, the measurement operation corresponding to the second measurement result is {|w - > <w - |,I-|w - > <w - |} measurement operation, where |w - > = sinθ|0> - i cosθ|1>; When the second measurement result is 1, the measurement operation corresponding to the first measurement result is {|w + > <w + |,I-|w + > <w + |} measurement operation, where |w + >=sinθ|0>+i cosθ|1>.

6. The method of claim 5, wherein: Determining that the measurement results on the first quantum system and the second quantum system are consistent with the expected results includes: when selecting the second verification scheme to measure the two-bit quantum state, In response to determining that the corresponding measurement result on the second quantum system is 0 and the corresponding measurement result on the first quantum system is w - , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results; In response to determining that the corresponding measurement result on the second quantum system is 1, and the corresponding measurement result on the first quantum system is w + , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results.

7. The method according to any one of claims 1 to 6, wherein: Determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results includes: when selecting a third verification scheme to perform the two-bit quantum state measurement, In response to determining that the corresponding measurement result on the first quantum system is 00 or 11, and the measurement result on the second quantum system is 00 or 11, it is determined that the measurement results on the first quantum system and the second quantum system both meet expected results.

8. The method of claim 1, wherein: The preset number N o Determined based on the following formula: Among them, ε is the preset error tolerance of the quantum device, and δ is the preset confidence level of errors in verifying the performance of the quantum device.

9. A quantum device performance verification device, comprising: The execution unit is configured to execute a first operation, wherein the first operation includes the following steps: generating, by the quantum device, a two-bit quantum state shared by a first quantum system and a second quantum system; Randomly select a scheme from a plurality of preset verification schemes to measure the two-bit quantum state to obtain a corresponding measurement result; A first determining unit is configured to repeatedly perform the first operation in response to determining that the measurement results on the first quantum system and the second quantum system both meet expected results and the number of executions of the first operation does not exceed a preset number of times; and The second determining unit is configured to determine that the quantum device can generate a two-bit quantum state that meets the requirements in response to the measurement results obtained after performing the first operation for a preset number of times all meet the expected results, wherein: The multiple verification schemes include: First verification scheme: performing an X measurement in the Pauli X, Y, Z measurement on the first quantum system to obtain a first measurement result, and performing a measurement operation corresponding to the first measurement result on the second quantum system; A second verification scheme: performing a Y measurement in the Pauli X, Y, Z measurement on the second quantum system to obtain a second measurement result, and performing a measurement operation corresponding to the second measurement result on the first quantum system; and A third verification scheme: performing Z measurement in the Pauli X, Y, Z measurement on both the first quantum system and the second quantum system.

10. The apparatus of claim 9, further comprising a second determining unit configured to: in response to measurement results on the first quantum system and the second quantum system not meeting expected results, determine that the quantum device is unable to generate a two-bit quantum state that meets the requirements.

11. The device of claim 9, wherein: When the first measurement result is 0, the measurement operation corresponding to the first measurement result is {|v + > <v + |,I-|v + > <v + |} measurement operation, where |v + >=sinθ|0>+cosθ|1>; When the first measurement result is 1, the measurement operation corresponding to the first measurement result is {|v - > <v - |,I-|v - > <v - |} measurement operation, where |v - >=sinθ|0>-cosθ|1>.

12. The device of claim 11, wherein: The first determining unit includes the first determining subunit, configured as follows: When the first verification scheme is selected to perform the two-bit quantum state measurement, In response to determining that the corresponding measurement result on the first quantum system is 0 and the corresponding measurement result on the second quantum system is v + , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results; In response to determining that the corresponding measurement result on the first quantum system is 1, and the corresponding measurement result on the second quantum system is v - , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results.

13. The device of claim 9, wherein: When the second measurement result is 0, the measurement operation corresponding to the second measurement result is {|w - > <w - |,I-|w - > <w - |} measurement operation, where |w - > = sinθ|0> - i cosθ|1>; When the second measurement result is 1, the measurement operation corresponding to the first measurement result is {|w + > <w + |,I-|w + > <w + |} measurement operation, where |w + >=sinθ|0>+i cosθ|1>.

14. The device of claim 13, wherein: The first determining unit includes the second determining subunit, configured as follows: When the second verification scheme is selected to perform the two-bit quantum state measurement, In response to determining that the corresponding measurement result on the second quantum system is 0 and the corresponding measurement result on the first quantum system is w - , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results; In response to determining that the corresponding measurement result on the second quantum system is 1, and the corresponding measurement result on the first quantum system is w + , determining that the measurement results on the first quantum system and the second quantum system are consistent with expected results.

15. The device according to any one of claims 9 to 14, wherein: The first determining unit includes a third determining subunit configured to: When the third verification scheme is selected to perform the two-bit quantum state measurement, In response to determining that the corresponding measurement result on the first quantum system is 00 or 11, and the measurement result on the second quantum system is 00 or 11, it is determined that the measurement results on the first quantum system and the second quantum system both meet expected results.

16. The device of claim 9, wherein: The preset number N o Determined based on the following formula: Among them, ε is the preset error tolerance of the quantum device, and δ is the preset confidence level of errors in verifying the performance of the quantum device.

17. An electronic device comprising: at least one processor; as well as a memory communicatively coupled to the at least one processor; in The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 8.

18. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-8.

19. A computer program product comprising a computer program, wherein: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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