CN116362341B - Quantum device unitary transformation degree determining method and device, electronic device and medium - Google Patents
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Abstract
The disclosure provides a unitary transformation degree determining method and device for quantum equipment, electronic equipment, a computer readable storage medium and a computer program product, and relates to the field of computers, in particular to the technical field of quantum computers. The implementation scheme is as follows: the following operations were performed N times in total: randomly sampling 2n quantum gates in a single-bit quantum gate set; the following operations are performed M times in total: randomly sampling a ground state in a preset standard ground state set to serve as a first quantum state; the transposition operation corresponding to the first n quantum gates in the 2n quantum gates is applied to each bit of the first quantum state, and a second quantum state is obtained; performing quantum operation on the second quantum state to obtain a third quantum state; sequentially applying the last n quantum gates to each bit of the third quantum state to obtain a fourth quantum state; standard base measurement is carried out on the fourth quantum state to obtain an input-output character string combination; and determining probability distribution of the occurrence of the character string combination so as to further determine the unitary transformation degree corresponding to the quantum operation.
Description
Technical Field
The present disclosure relates to the field of computers, and in particular, to the field of quantum computer technology, and more particularly, to a method, an apparatus, an electronic device, a computer readable storage medium, and a computer program product for determining unitary transformation degree of a quantum device.
Background
Quantum computing is the core of the next generation computing technology, and is also a break of new industrial revolution, and related technologies are rapidly developing. With the rapid development of Quantum hardware, the times of noisy medium-Scale quanta (Noisy Intermediate-Scale Quantum, NISQ) come, and Quantum equipment in the stage has 50-100 physical Quantum bits, and the quantity and the quality of the Quantum equipment reach the degree that a classical computer is difficult to simulate. Ideally, the quantum device implements unitary transformation (unitary transformation) evolution.
But noise problems in foreseeable future quantum devices are difficult to avoid: the heat dissipation in the qubit or random fluctuation generated in the underlying quantum physical process can lead to the evolution process implemented by the quantum device not being unitary transformation any more, but the evolution process of non-unitary transformation can lead to, for example, state inversion or randomization of the qubit, so that the whole calculation process fails.
Disclosure of Invention
The present disclosure provides a quantum device unitary transformation degree determination method, apparatus, electronic device, computer-readable storage medium, and computer program product.
According to an aspect of the present disclosure, there is provided a unitary transform degree determining method for a quantum device, including: performing the following operations N times, wherein N is a positive integer; randomly sampling 2n single-bit quantum gates in a preset single-bit quantum gate set, wherein n is the number of quantum bits corresponding to the corresponding quantum operation of the quantum equipment, and n is a positive integer; performing the following operations M times, wherein M is a positive integer; randomly sampling a ground state in a preset n-bit standard ground state set to serve as a first quantum state; the transposition operation corresponding to each of the first n quantum gates in the 2n single-bit quantum gates is sequentially applied to each quantum bit of the first quantum state, so as to obtain a second quantum state; obtaining a third quantum state by performing the quantum operation on the second quantum state; sequentially applying the last n quantum gates of the 2n single-bit quantum gates to each quantum bit of the third quantum state to obtain a fourth quantum state; performing standard base measurement on the fourth quantum state to obtain a first character string, wherein the character string corresponding to the first quantum state and the first character string form a character string combination; determining probability distribution of each identical character string combination based on all character string combinations obtained after the M times of operation; and determining the unitary transformation degree corresponding to the quantum operation of the quantum equipment based on the probability distribution obtained after N times of operation, the similarity between the character strings corresponding to the first quantum states and the similarity between the first character strings.
According to another aspect of the present disclosure, there is provided a unitary transformation degree determining apparatus for a quantum device, including: an operation unit configured to perform the following operations a total of N times, where N is a positive integer; randomly sampling 2n single-bit quantum gates in a preset single-bit quantum gate set, wherein n is the number of quantum bits corresponding to the corresponding quantum operation of the quantum equipment, and n is a positive integer; performing the following operations M times, wherein M is a positive integer; randomly sampling a ground state in a preset n-bit standard ground state set to serve as a first quantum state; the transposition operation corresponding to each of the first n quantum gates in the 2n single-bit quantum gates is sequentially applied to each quantum bit of the first quantum state, so as to obtain a second quantum state; obtaining a third quantum state by performing the quantum operation on the second quantum state; sequentially applying the last n quantum gates of the 2n single-bit quantum gates to each quantum bit of the third quantum state to obtain a fourth quantum state; performing standard base measurement on the fourth quantum state to obtain a first character string, wherein the character string corresponding to the first quantum state and the first character string form a character string combination; determining probability distribution of each identical character string combination based on all character string combinations obtained after the M times of operation; and a determining unit configured to determine a unitary transformation degree corresponding to the quantum operation of the quantum device based on the probability distribution obtained after the N operations, the similarity between the character strings corresponding to the respective first quantum states, and the similarity between the respective first character strings.
According to another aspect of the present disclosure, there is provided an electronic device including: at least one processor; and a memory communicatively coupled to the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the methods described in the present disclosure.
According to another aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method described in the present disclosure.
According to another aspect of the present disclosure, there is provided a computer program product comprising a computer program which, when executed by a processor, implements the method described in the present disclosure.
According to one or more embodiments of the present disclosure, the objective of estimating the unitary transformation degree of a quantum device with fewer quantum resources is achieved by randomly sampling the system input states to equivalently simulate the effects of auxiliary quantum bits, independent of the auxiliary quantum bits.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following specification.
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The accompanying drawings illustrate exemplary embodiments and, together with the description, serve to explain exemplary implementations of the embodiments. The illustrated embodiments are for exemplary purposes only and do not limit the scope of the claims. Throughout the drawings, identical reference numerals designate similar, but not necessarily identical, elements.
FIG. 1 shows a schematic diagram of obtaining a quantum state for a quantum operation according to an embodiment of the present disclosure;
fig. 2 shows a schematic diagram of a unitary transformation degree estimation method according to an embodiment of the present disclosure;
fig. 3 shows a flow chart of a quantum device unitary transform degree determination method according to an embodiment of the present disclosure;
Fig. 4 shows a schematic diagram of another unitary transformation degree estimation method according to an embodiment of the present disclosure;
fig. 5 shows a block diagram of a quantum device unitary transformation degree determining apparatus according to an embodiment of the present disclosure; and
Fig. 6 illustrates a block diagram of an exemplary electronic device that can be used to implement embodiments of the present disclosure.
Detailed Description
Exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings, which include various details of the embodiments of the present disclosure to facilitate understanding, and should be considered as merely exemplary. Accordingly, one of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the present disclosure. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.
In the present disclosure, the use of the terms "first," "second," and the like to describe various elements is not intended to limit the positional relationship, timing relationship, or importance relationship of the elements, unless otherwise indicated, and such terms are merely used to distinguish one element from another. In some examples, a first element and a second element may refer to the same instance of the element, and in some cases, they may also refer to different instances based on the description of the context.
The terminology used in the description of the various illustrated examples in this disclosure is for the purpose of describing particular examples only and is not intended to be limiting. Unless the context clearly indicates otherwise, the elements may be one or more if the number of the elements is not specifically limited. Furthermore, the term "and/or" as used in this disclosure encompasses any and all possible combinations of the listed items.
Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.
To date, various types of computers in use are based on classical physics as the theoretical basis for information processing, known as traditional or classical computers. Classical information systems store data or programs using binary data bits that are physically easiest to implement, each binary data bit being represented by a 0 or a1, called a bit or a bit, as the smallest unit of information. Classical computers themselves have the inevitable weakness: first, the most basic limitation of energy consumption in the calculation process. The minimum energy required by the logic element or the memory cell should be more than several times of kT to avoid malfunction under thermal expansion; secondly, information entropy and heating energy consumption; thirdly, when the wiring density of the computer chip is large, the uncertainty of momentum is large when the uncertainty of the electronic position is small according to the uncertainty relation of the Hessenberg. Electrons are no longer bound and there is a quantum interference effect that can even destroy the performance of the chip.
Quantum computers (or quantum devices) are a class of physical devices that perform high-speed mathematical and logical operations, store, and process quantum information in compliance with quantum mechanical properties, laws. When a device processes and calculates quantum information and a quantum algorithm is operated, the device is a quantum computer. Quantum computers follow unique quantum dynamics (particularly quantum interferometry) to achieve a new model of information processing. For parallel processing of computational problems, quantum computers have an absolute advantage in speed over classical computers. The transformation implemented by the quantum computer on each superposition component is equivalent to a classical computation, all of which are completed simultaneously and are superimposed according to a certain probability amplitude to give the output result of the quantum computer, and the computation is called quantum parallel computation. Quantum parallel processing greatly improves the efficiency of quantum computers so that they can perform tasks that classical computers cannot do, such as factorization of a large natural number. Quantum coherence is essentially exploited in all quantum ultrafast algorithms. Therefore, quantum parallel computation with quantum state instead of classical state can reach incomparable operation speed and information processing function of classical computer, and save a large amount of operation resources.
With the rapid development of quantum computer technology, quantum computers are increasingly used because of their powerful computing power and faster operating speeds. For example, chemical simulation refers to a process of mapping the hamiltonian of a real chemical system to a physically operable hamiltonian, and then modulating parameters and evolution time to find an eigenstate that can reflect the real chemical system. When an N-electron chemical system is simulated on a classical computer, the solution of a 2 N -dimensional Schrodinger equation is involved, and the calculated amount increases exponentially with the increase of the electron number of the system. Classical computers therefore have very limited utility in chemical simulation problems. To break this bottleneck, one must rely on the powerful computational power of quantum computers. The quantum eigensolver algorithm (Variational Quantum Eigensolver, VQE) is a high-efficiency quantum algorithm for performing chemical simulation on quantum hardware, is one of the most promising applications of quantum computers recently, and opens up a number of new chemical research fields.
Ideally, quantum computers implement unitary transformation (unitary transformation) evolution, which is completely reversible and theoretically does not consume heat. But noise problems in foreseeable future quantum devices are difficult to avoid: the heat dissipation in the qubit or random fluctuation generated in the underlying quantum physical process can lead to the evolution process implemented by the quantum device not being unitary transformation any more, but the evolution process of non-unitary transformation can lead to, for example, state inversion or randomization of the qubit, so that the whole calculation process fails.
Therefore, before implementing VQE equivalent sub-algorithms on a quantum computer or fully practical for a quantum computer, a method is needed to quickly, efficiently and accurately estimate the unitary transformation degree (unitary degree) of a quantum device, i.e., whether the target quantum device implements a unitary transformation? How far apart from unitary transformation is the evolution process implemented by the quantum device if not? According to unitary transformation degree of the target quantum computer, whether the target quantum computer can be used for an actual quantum computing process is decided according to an actual problem.
In general, the unitary transformation degree of a quantum device may be estimated based on a quantum process tomography (Quantum Process Tomography) or quantum gate set tomography (Quantum Gateset Tomography) method. The core ideas of the two schemes are that the evolution Process actually realized by the target quantum device is completely calculated, namely all information of the evolution Process (generally called a Process Matrix in theory) is obtained, then an approximate optimization algorithm is used for judging whether the Process Matrix corresponds to a unitary Matrix or not and how far the Process Matrix deviates from the unitary Matrix, and the purpose of estimating the unitary transformation degree of the quantum device is realized.
But the quantum resources consumed by quantum chromatography (number of quantum states to be prepared and number of measurements to be made) increase exponentially with the increase in the number of qubits n of the target quantum device. For example, the complexity of the quantum process chromatography algorithm is O (16 n). In practical physical experiments, the data required to be collected by quantum devices with more than three qubits are very large when using quantum chromatography techniques, so the method has no practicability.
To estimate the unitary transform degree of quantum evolution, a measure (metric) that can be used to characterize the unitary transform degree needs to be defined first. It will be appreciated that the Choi quantum states corresponding to unitary transform evolution are Pure states (Pure states), while the Choi quantum states corresponding to all non-unitary transform evolutions supported by the quantum device are Mixed states (Mixed states). Choi quantum state is a legal quantum state. The Purity (Purity) of one legal quantum state ρ may be defined as Tr [ ρ 2 ], which satisfies the inequality 0+.ltoreq.tr [ ρ 2 ] +.1, and ρ is the pure state if and only if Tr [ ρ 2 ] =1.
Thus, it may be determined whether the target quantum evolution is a unitary transformation by determining whether the Choi quantum state to which the target quantum evolution corresponds is a pure state. Specifically, the unitary transform degree measure may be defined as follows:
That is to say, Is the purity of the Choi quantum state. That is to say that the first and second,The unitary transformation degree of quantum evolution is characterized to a certain extent. The defined unitary transform degree measure satisfies the property: for all quantum evolution ε supported by the quantum device, the measure satisfiesAnd if and only if the quantum evolution ε is unitary transformation
Mathematically, the quantum evolution epsilon supported by a quantum device can be expressed using quantum operations (Quantum Operation). It will be appreciated that Quantum evolution epsilon is sometimes also referred to as Quantum Channel (Quantum Channel), quantum Process (Quantum Process), without limitation herein. If epsilon can be expressed asIn the form of (where U is a unitary matrix,A conjugate transpose (Conjugate Transpose) representing the matrix), then the weighing sub-operation epsilon is a unitary transform; otherwise, ε is a non-unitary transformation.
Assuming that the quantum operation epsilon is an n-bit quantum operation, i.e. epsilon acts on an n-bit quantum state, and outputs an n-bit quantum state, the Choi quantum state corresponding to epsilon is defined as:
Where id represents an n-qubit identity operation, and |Φ + > is the maximum entangled state of 2 n-qubits defined on a standard basis, namely:
Where i > represents the calculated ground state. When n=1, |Φ + > is the common Bell state. The preparation process of the Choi quantum state corresponding to the quantum operation epsilon can be shown in figure 1.
Referring to fig. 1, in defining a Choi quantum state corresponding to a quantum operation epsilon, n auxiliary qubits are additionally introduced, so that the whole system has 2n qubits, and the quantum operation epsilon only acts on n qubits therein. Therefore, the maximum entangled state needs to be prepared on 2n qubits, so that n qubits and n auxiliary quantum ratios of the original system are entangled very much.
Fig. 2 shows a schematic diagram of a unitary transformation degree estimation method according to an exemplary embodiment of the present disclosure. As shown in FIG. 2, the unitary transformation degree estimation method firstly uses auxiliary quantum bits to construct Choi quantum states corresponding to quantum operations epsilon, then estimates the purity of the Choi quantum states through random measurement, and further estimates and obtains the unitary transformation degreeIs a similar estimate of (a).
But in the examples shown in figures 1 and 2 additional resources are required to introduce n qubits and more bits of quantum gates (at least two bits of quantum gates are required) are required to prepare the Choi quantum state. The multi-bit quantum gate precision of the present-stage quantum device is generally at least one dimension lower than the single-bit quantum gate precision. Thus, when using multi-bit quantum gates to prepare Choi quantum states, more noise is introduced, which is attributed to the target quantum device, resulting in poor accuracy of the estimated unitary transformation.
Accordingly, embodiments in accordance with the present disclosure provide a quantum device unitary transform degree determination method. Fig. 3 shows a flow chart of a method of determining a unitary degree of transformation of a quantum device according to an embodiment of the disclosure, as shown in fig. 3, the method 300 includes: performing the following operations a total of N times, wherein N is a positive integer (step 310); randomly sampling 2n single-bit quantum gates in a preset single-bit quantum gate set in a put-back way, wherein n is the number of quantum bits corresponding to the corresponding quantum operation of the quantum device, and n is a positive integer (step 3101); performing the following operations a total of M times, wherein M is a positive integer (step 3102); randomly sampling a ground state in a preset n-bit standard ground state set to serve as a first quantum state (step 31021); the transposition operation corresponding to each of the first n quantum gates in the 2n single-bit quantum gates is sequentially applied to each quantum bit of the first quantum state to obtain a second quantum state (step 31022); obtaining a third quantum state by performing the quantum operation on the second quantum state (step 31023); sequentially applying the last n quantum gates of the 2n single bit quantum gates to each quantum bit of the third quantum state to obtain a fourth quantum state (step 31024); and performing standard base measurement on the fourth quantum state to obtain a first character string, wherein the character string corresponding to the first quantum state and the first character string form a character string combination (step 31025); determining probability distribution of each identical character string combination based on all character string combinations obtained after the M operations (step 3103); and determining a unitary transformation degree corresponding to the quantum operation of the quantum device based on the probability distribution obtained after the N operations, the similarity between the strings corresponding to the respective first quantum states, and the similarity between the respective first strings (step 320).
According to the embodiment of the disclosure, independent of auxiliary quantum bits, the effect of the auxiliary quantum bits is simulated equivalently by randomly sampling the input states of the system, so that the aim of estimating the unitary transformation degree of the quantum device by using fewer quantum resources is fulfilled.
In the present disclosure, the delay measurement principle (Deferred Measurement Principle) in quantum computing is further exploited to remove the dependence on auxiliary qubits. Specifically, as in the example shown in fig. 2, only single bit quantum gates and standard base measurements are used. Thus, the single-bit quantum gate U a (subscript a denotes ancilla, i.e., an auxiliary system) and the standard base measurement operation acting on the auxiliary qubit can be performed in advance, as shown in fig. 4. After these two operations of the auxiliary qubit are completed, the following equation is used:
Wherein, Transpose (Transpose) of the representation matrix U a, it can be appreciated that if the output of the auxiliary qubit is s a, then the n-bit quantum state of the host system is changed accordingly toEquivalent to use ofAs a main system input.
By utilizing the delay measurement principle, auxiliary quantum bits can be removed, the input state of the main system is randomly sampled, and the auxiliary quantum bit effect is equivalently simulated based on a sampling result. Meanwhile, because the input state of the auxiliary quantum bit is half of the maximum entangled state, namely the n-bit maximum mixed state, the probability of the output result of the auxiliary quantum bit s a is 1/2 n, which gives the probability distribution of the randomly sampled input state.
According to some embodiments, determining the unitary transformation degree corresponding to the quantum operation of the quantum device based on the probability distribution obtained after N operations, the similarity between the strings corresponding to the respective first quantum states, and the similarity between the respective first strings comprises: for each character string combination in all character string combinations obtained after the M times of operation, determining the product of probability distribution corresponding to the character string combination and probability distribution of each character string combination in all character string combinations; and determining the unitary transformation degree corresponding to the quantum operation of the quantum device based on the product of the probability distribution determined after N times of operation, the similarity between the character strings corresponding to the first quantum states and the similarity between the first character strings.
Specifically, after M operations are performed, a count (a large number of repetitions may occur) of a string combination (s i,so) formed by the input string s i and the output string s o (corresponding to one 2 n-bit string) is obtained. Illustratively, these string combinations (s i,so) may be rearranged and counted as the number of occurrences of the same string (s i,so)To calculate a probability distribution:
wherein, the subscript k represents the probability distribution corresponding to the kth operation in the N operations.
From the probability distribution obtained after N operations, the unitary transformation degree can be calculated using the following formulaIs a approximation of:
Wherein, Representing the similarity between the input strings s i and s' i,Representing the similarity between the output strings s o and s' o, and
Output ofAs unitary transformation degreeIs a similar estimate of (a).
According to some embodiments, the single-bit quantum gates in the set of single-bit quantum gates satisfy unitary-design properties.
According to some embodiments, the similarity between the strings corresponding to the respective first quantum states includes a hamming distance (HAMMING DISTANCE).
In one exemplary embodiment according to the present disclosure, a unitary transformation degree for determining n-qubit quantum operations epsilon implemented by a quantum device. First, a quantum gate random sampling number N, a measurement repetition number M (e.g., equal to l×s, where L represents the input state sampling number and S represents the measurement repetition number) are determined. Then, the following operation steps are performed:
step 1: let k=1. The quantum system is initialized to 2n qubits.
Step 2: 2n single-bit quantum gates are sampled randomly with a put back from a set of single-bit quantum gates satisfying unitary-design. It is assumed that these quantum gates have been numbered in the order 1,2, …,2 n.
Step 2.1: the following steps were repeated M times in total:
step 2.1.1: in n-qubit standard ground state set The uniformly random replaced sample quantum state |s i >, wherein the subscript i represents the Input (Input);
step 2.1.2: the transpose of the first n single bit quantum gates is sequentially applied to the quantum states obtained in step 2.1.1.
Step 2.1.3: and (3) enabling the quantum equipment epsilon to act on the quantum state obtained in the step 2.1.2.
Step 2.1.4: the remaining n single bit quantum gates are sequentially applied to the quantum states obtained in step 2.1.3.
Step 2.1.5: the quantum state obtained in step 2.1.4 is measured using standard basis measurements, resulting in an n-bit string s o, where the subscript o represents the Output (Output). An input-output string (s i,so) count is obtained after steps 2.1.1-2.1.5 are completed.
Step 2.2: after step 2.1 is completed, a total of M I-O string (s i,so) counts are obtained (a large number of repetitions may occur). Rearranging the input-output strings and counting (s i,so) the number of occurrencesCalculating probability distribution: Where the subscript k indicates that this is the probability distribution for the kth round of single bit quantum gate sampling.
Step 3: let k=k+1. If k is less than or equal to N, jumping to the 2 nd step for the next sampling iteration; otherwise, jumping to step 3.
Step 4: to this end, N probability distributions Pr k(si,so are obtained, which are defined on the input-output string (s i,so).
Step 5: calculating a unitary transform degree using the following formulaIs a approximation of:
Wherein, Representing the hamming distance between the input strings s i and s' i,Representing the hamming distance between the output strings s o and s' o. Thereby, it is obtainedAs an approximate estimate of the degree of unitary transformation.
There is also provided, as shown in fig. 5, a unitary transformation degree determining apparatus 500 for quantum devices according to an embodiment of the present disclosure, including: an operation unit 510 configured to perform the following operations a total of N times, where N is a positive integer; randomly sampling 2n single-bit quantum gates in a preset single-bit quantum gate set, wherein n is the number of quantum bits corresponding to the corresponding quantum operation of the quantum equipment, and n is a positive integer; performing the following operations M times, wherein M is a positive integer; randomly sampling a ground state in a preset n-bit standard ground state set to serve as a first quantum state; the transposition operation corresponding to each of the first n quantum gates in the 2n single-bit quantum gates is sequentially applied to each quantum bit of the first quantum state, so as to obtain a second quantum state; obtaining a third quantum state by performing the quantum operation on the second quantum state; sequentially applying the last n quantum gates of the 2n single-bit quantum gates to each quantum bit of the third quantum state to obtain a fourth quantum state; performing standard base measurement on the fourth quantum state to obtain a first character string, wherein the character string corresponding to the first quantum state and the first character string form a character string combination; determining probability distribution of each identical character string combination based on all character string combinations obtained after the M times of operation; and a determining unit 520 configured to determine a unitary transformation degree corresponding to the quantum operation of the quantum device based on the probability distribution obtained after N operations, the similarity between the strings corresponding to the respective first quantum states, and the similarity between the respective first strings.
Here, the operations of the above units 510 to 520 of the unitary transformation degree determining apparatus 500 for quantum devices are similar to the operations of the steps 310 to 320 described above, respectively, and are not repeated here.
According to embodiments of the present disclosure, there is also provided an electronic device, a readable storage medium and a computer program product.
Referring to fig. 6, a block diagram of an electronic device 600 that may be a server or a client of the present disclosure, which is an example of a hardware device that may be applied to aspects of the present disclosure, will now be described. Electronic devices are intended to represent various forms of digital electronic computer devices, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the disclosure described and/or claimed herein.
As shown in fig. 6, the electronic device 600 includes a computing unit 601 that can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM) 602 or a computer program loaded from a storage unit 608 into a Random Access Memory (RAM) 603. In the RAM 603, various programs and data required for the operation of the electronic device 600 can also be stored. The computing unit 601, ROM 602, and RAM 603 are connected to each other by a bus 604. An input/output (I/O) interface 605 is also connected to bus 604.
A number of components in the electronic device 600 are connected to the I/O interface 605, including: an input unit 606, an output unit 607, a storage unit 608, and a communication unit 609. The input unit 606 may be any type of device capable of inputting information to the electronic device 600, the input unit 606 may receive input numeric or character information and generate key signal inputs related to user settings and/or function control of the electronic device, and may include, but is not limited to, a mouse, a keyboard, a touch screen, a trackpad, a trackball, a joystick, a microphone, and/or a remote control. The output unit 607 may be any type of device capable of presenting information and may include, but is not limited to, a display, speakers, video/audio output terminals, vibrators, and/or printers. Storage unit 608 may include, but is not limited to, magnetic disks, optical disks. The communication unit 609 allows the electronic device 600 to exchange information/data with other devices through a computer network, such as the internet, and/or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers and/or chipsets, such as bluetooth devices, 802.11 devices, wiFi devices, wiMax devices, cellular communication devices, and/or the like.
The computing unit 601 may be a variety of general and/or special purpose processing components having processing and computing capabilities. Some examples of computing unit X01 include, but are not limited to, a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), various specialized Artificial Intelligence (AI) computing chips, various computing units running machine learning model algorithms, a Digital Signal Processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 601 performs the various methods and processes described above, such as method 300. For example, in some embodiments, the method 300 may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as the storage unit 608. In some embodiments, part or all of the computer program may be loaded and/or installed onto the electronic device 600 via the ROM 602 and/or the communication unit 609. One or more of the steps of the method 300 described above may be performed when a computer program is loaded into RAM 603 and executed by the computing unit 601. Alternatively, in other embodiments, computing unit 601 may be configured to perform method 300 by any other suitable means (e.g., by means of firmware).
Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuit systems, field Programmable Gate Arrays (FPGAs), application Specific Integrated Circuits (ASICs), application Specific Standard Products (ASSPs), systems On Chip (SOCs), complex Programmable Logic Devices (CPLDs), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include: implemented in one or more computer programs, the one or more computer programs may be executed and/or interpreted on a programmable system including at least one programmable processor, which may be a special purpose or general-purpose programmable processor, that may receive data and instructions from, and transmit data and instructions to, a storage system, at least one input device, and at least one output device.
Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the context of this disclosure, a machine-readable medium may be a tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and pointing device (e.g., a mouse or trackball) by which a user can provide input to the computer. Other kinds of devices may also be used to provide for interaction with a user; for example, feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form, including acoustic input, speech input, or tactile input.
The systems and techniques described here can be implemented in a computing system that includes a background component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a user computer having a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such background, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: local Area Networks (LANs), wide Area Networks (WANs), the internet, and blockchain networks.
The computer system may include a client and a server. The client and server are typically remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server may be a cloud server, a server of a distributed system, or a server incorporating a blockchain.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps recited in the present disclosure may be performed in parallel, sequentially or in a different order, provided that the desired results of the disclosed aspects are achieved, and are not limited herein.
Although embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it is to be understood that the foregoing methods, systems, and apparatus are merely exemplary embodiments or examples, and that the scope of the present invention is not limited by these embodiments or examples but only by the claims following the grant and their equivalents. Various elements of the embodiments or examples may be omitted or replaced with equivalent elements thereof. Furthermore, the steps may be performed in a different order than described in the present disclosure. Further, various elements of the embodiments or examples may be combined in various ways. It is important that as technology evolves, many of the elements described herein may be replaced by equivalent elements that appear after the disclosure.
Claims (11)
1. A method for determining a unitary transform degree of a quantum device, comprising:
Performing the following operations N times, wherein N is a positive integer;
Randomly sampling 2n single-bit quantum gates in a preset single-bit quantum gate set, wherein n is the number of quantum bits corresponding to the corresponding quantum operation of the quantum equipment, and n is a positive integer;
performing the following operations M times, wherein M is a positive integer;
randomly sampling a ground state in a preset n-bit standard ground state set to serve as a first quantum state;
The transposition operation corresponding to each of the first n quantum gates in the 2n single-bit quantum gates is sequentially applied to each quantum bit of the first quantum state, so as to obtain a second quantum state;
obtaining a third quantum state by performing the quantum operation on the second quantum state;
Sequentially applying the last n quantum gates of the 2n single-bit quantum gates to each quantum bit of the third quantum state to obtain a fourth quantum state; and
Performing standard base measurement on the fourth quantum state to obtain a first character string, wherein the character string corresponding to the first quantum state and the first character string form a character string combination; determining probability distribution of each identical character string combination based on all character string combinations obtained after the M times of operation; and
And determining the unitary transformation degree corresponding to the quantum operation of the quantum equipment based on the probability distribution obtained after N times of operation, the similarity between the character strings corresponding to the first quantum states and the similarity between the first character strings.
2. The method of claim 1, wherein determining the unitary transformation degree corresponding to the quantum operation of the quantum device based on the probability distribution obtained after N operations, the similarity between strings corresponding to each first quantum state, and the similarity between each first string comprises:
for each character string combination in all character string combinations obtained after the M times of operation, determining the product of probability distribution corresponding to the character string combination and probability distribution of each character string combination in all character string combinations; and
And determining the unitary transformation degree corresponding to the quantum operation of the quantum equipment based on the product of the probability distribution determined after N times of operation, the similarity between the character strings corresponding to the first quantum states and the similarity between the first character strings.
3. The method of claim 1, wherein a single-bit quantum gate in the set of single-bit quantum gates satisfies unitary-design properties.
4. The method of claim 1, wherein the similarity between strings corresponding to each first quantum state and the similarity between the first strings comprise hamming distances.
5. A quantum device unitary transform degree determining apparatus, comprising:
an operation unit configured to perform the following operations a total of N times, where N is a positive integer;
Randomly sampling 2n single-bit quantum gates in a preset single-bit quantum gate set, wherein n is the number of quantum bits corresponding to the corresponding quantum operation of the quantum equipment, and n is a positive integer;
performing the following operations M times, wherein M is a positive integer;
randomly sampling a ground state in a preset n-bit standard ground state set to serve as a first quantum state;
The transposition operation corresponding to each of the first n quantum gates in the 2n single-bit quantum gates is sequentially applied to each quantum bit of the first quantum state, so as to obtain a second quantum state;
obtaining a third quantum state by performing the quantum operation on the second quantum state;
Sequentially applying the last n quantum gates of the 2n single-bit quantum gates to each quantum bit of the third quantum state to obtain a fourth quantum state; and
Performing standard base measurement on the fourth quantum state to obtain a first character string, wherein the character string corresponding to the first quantum state and the first character string form a character string combination;
Determining probability distribution of each identical character string combination based on all character string combinations obtained after the M times of operation; and
And the determining unit is configured to determine the unitary transformation degree corresponding to the quantum operation of the quantum equipment based on the probability distribution obtained after N times of operation, the similarity between the character strings corresponding to the first quantum states and the similarity between the first character strings.
6. The apparatus of claim 5, wherein the determining unit comprises:
A first determining subunit configured to determine, for each of the all the character string combinations obtained after the M operations, a product of a probability distribution corresponding to the character string combination and a probability distribution of each of the all the character string combinations; and
And the second determining subunit is configured to determine the unitary transformation degree corresponding to the quantum operation of the quantum device based on the product of the probability distribution determined after N times of operation, the similarity between the character strings corresponding to the first quantum states and the similarity between the first character strings.
7. The apparatus of claim 5, wherein a single-bit quantum gate in the set of single-bit quantum gates satisfies unitary-design properties.
8. The apparatus of claim 5, wherein the similarity between strings corresponding to each first quantum state and the similarity between the first strings comprise hamming distances.
9. An electronic device, comprising:
At least one processor; and
A memory communicatively coupled to the at least one processor; wherein the method comprises the steps of
The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-4.
10. A non-transitory computer readable storage medium storing computer instructions for causing the computer to perform the method of any one of claims 1-4.
11. A computer program product comprising a computer program, wherein the computer program, when executed by a processor, implements the method of any of claims 1-4.
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| CN115587630A (en) * | 2022-09-28 | 2023-01-10 | 北京百度网讯科技有限公司 | Cross-platform quantum device entanglement verification method and device, electronic device and medium |
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| CN115587630A (en) * | 2022-09-28 | 2023-01-10 | 北京百度网讯科技有限公司 | Cross-platform quantum device entanglement verification method and device, electronic device and medium |
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