Method and device for acquiring XY crosstalk matrix of quantum chip and quantum computer

Abstract

The invention discloses a quantum chip XY crosstalk matrix obtaining method and device and a quantum computer, and the method comprises the steps: obtaining an XY crosstalk coefficient between quantum bits in a to-be-measured sub-chip based on an experiment result of a crosstalk Ramsey experiment, and the crosstalk Ramsey experiment is that when a first quantum bit has XY crosstalk on a second quantum bit, the XY crosstalk coefficient between the quantum bits in the to-be-measured sub-chip is determined to be the XY crosstalk coefficient between the quantum bits in the to-be-measured sub-chip; a compensation signal is applied to the second quantum bit, a Ramsey experiment is executed on the second quantum bit, the change condition of the probability of the second quantum bit in the first selected eigenstate along with the compensation signal parameter is obtained, and the first quantum bit and the second quantum bit are any two quantum bits in the to-be-measured sub-chip. And obtaining an XY crosstalk matrix based on the obtained XY crosstalk coefficient. According to the scheme, the XY crosstalk matrix of the quantum chip can be effectively obtained, and the blank in the prior art is filled.

Description

Technical Field

[0001] The present invention relates to the field of quantum computing technology, and in particular to a method and device for obtaining an XY crosstalk matrix of a quantum chip, and a quantum computer. Background Art

[0002] Quantum computing and quantum information is an interdisciplinary subject based on the principles of quantum mechanics to achieve computing and information processing tasks. It has a very close connection with quantum physics, computer science, informatics and other disciplines, and has developed rapidly in the past two decades. Quantum algorithms based on quantum computers in scenarios such as factorization and unstructured search have shown performance far beyond the existing algorithms based on classical computers, and this direction has also been expected to exceed existing computing capabilities. Since quantum computing has the potential to far exceed the performance of classical computers in solving specific problems, in order to realize a quantum computer, it is necessary to obtain a quantum chip that contains a sufficient number and quality of quantum bits, and can perform quantum logic gate operations and read quantum bits with extremely high fidelity.

[0003] The quantum chip is to the quantum computer what the CPU is to the traditional computer. The quantum chip is the core component of the quantum computer. The quantum chip is the processor that performs quantum computing. The quantum chip integrates multiple one-to-one and mutually coupled quantum bits and reading cavities. Each quantum chip needs to be tested and characterized before it is officially put into use. The quantum computer also includes a measurement and control system that provides a measurement and control environment for the quantum chip. The measurement and control system mainly includes hardware equipment located in the room temperature layer and low-temperature devices and signal transmission lines located in the dilution refrigerator. After the quantum chip is packaged, it is fixed in the extremely low temperature layer of the bottom layer of the dilution refrigerator, and finally connected to the hardware equipment at room temperature through the coaxial line between the layers. In this measurement and control system, when regulating the quantum state of the quantum bit, two types of lines are mainly used. One is the first type of transmission line (also known as the quantum state control line, XY line) used to drive the quantum state of the quantum bit, and the other is the second type of transmission line (also known as the frequency control line, Z line) used to regulate the frequency of the quantum bit. The signal transmitted on the quantum state control line is called the quantum state control signal, and the signal transmitted on the frequency control line is called the frequency control signal. In a quantum chip, the quantum state control signal of a quantum bit will be affected by the quantum state control signal of an adjacent quantum bit. For example, when an X-gate signal is applied to the quantum state control line of the first quantum bit, a quantum state control signal is also applied to the quantum state control line of the second quantum bit adjacent to the quantum bit. Due to the existence of this influence, the first quantum bit that should have been excited to the |1> state by the X-gate signal will still be in the ground state or excited to a higher quantum state. We generally call this phenomenon XY crosstalk. If this crosstalk effect is ignored and no treatment is done, serious errors will occur in quantum computing tasks.

[0004] Therefore, proposing a solution that can measure the XY crosstalk matrix of a quantum chip has become an urgent issue in this field.

[0005] It should be noted that the information disclosed in the background technology section of this application is only intended to deepen the understanding of the general background technology of this application, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a method, device and quantum computer for obtaining the XY crosstalk matrix of a quantum chip, so as to solve the problem that there is a lack of a solution for measuring the XY crosstalk matrix of a quantum chip in the prior art.

[0007] In order to solve the above technical problems, the present invention proposes a method for obtaining the XY crosstalk matrix of a quantum chip, comprising:

[0008] Based on the experimental results of the crosstalk Ramsey experiment, an XY crosstalk coefficient between quantum bits in the quantum chip to be measured is obtained, wherein the crosstalk Ramsey experiment is to apply a compensation signal to the second quantum bit and perform a Ramsey experiment on the second quantum bit when there is XY crosstalk between the first quantum bit and the second quantum bit, and obtain the probability of the second quantum bit being in a first selected eigenstate as the compensation signal parameter changes, and the first quantum bit and the second quantum bit are any two quantum bits in the quantum chip to be measured;

[0009] Based on the obtained XY crosstalk coefficients, an XY crosstalk matrix is ​​obtained.

[0010] Optionally, the XY crosstalk coefficient is obtained in the following manner:

[0011] When the first qubit has an XY crosstalk effect on the second qubit, applying a compensation signal to the second qubit and performing a Ramsey experiment on the second qubit;

[0012] According to the experimental result of the Ramsey experiment, obtaining a first change in the probability of the second quantum bit being in the first selected eigenstate as a function of the parameter of the compensation signal;

[0013] An XY crosstalk coefficient of the first quantum bit to the second quantum bit is obtained based on the first change condition.

[0014] Optionally, the compensation signal is applied to the quantum state control line of the second quantum bit between two X / 2 gates in the Ramsey experiment.

[0015] Optionally, a quantum state control signal is applied to the quantum state control line of the first quantum bit so that the first quantum bit generates XY crosstalk on the second quantum bit, and the quantum state control signal applied to the quantum state control line of the first quantum bit is aligned in timing with the compensation signal.

[0016] Optionally, obtaining an XY crosstalk coefficient of the first qubit to the second qubit based on the first change includes:

[0017] Based on the first change, obtaining the amplitude of the compensation signal corresponding to the extreme point of the probability that the second quantum bit is in the first selected eigenstate is a first value;

[0018] The XY crosstalk coefficient of the first quantum bit to the second quantum bit is obtained based on the ratio of the first numerical value to the second numerical value, where the second numerical value is the amplitude of the quantum state control signal applied to the first quantum bit.

[0019] Optionally, the parameters of the compensation signal include amplitude, phase, frequency, and pulse width.

[0020] Optionally, the frequency of the compensation signal is the same as the frequency of the quantum state control signal applied to the first quantum bit, and the pulse width of the compensation signal is the same as the pulse width of the quantum state control signal applied to the first quantum bit.

[0021] Based on the same inventive concept, the present invention also proposes a device for obtaining the XY crosstalk matrix of a quantum chip, comprising:

[0022] A crosstalk coefficient acquisition unit, used for acquiring an XY crosstalk coefficient between quantum bits in the sub-chip to be measured based on an experimental result of a crosstalk Ramsey experiment, wherein the crosstalk Ramsey experiment is to apply a compensation signal to a second quantum bit and perform a Ramsey experiment on the second quantum bit when an XY crosstalk exists between a first quantum bit and a second quantum bit, and to acquire a probability that the second quantum bit is in a first selected eigenstate as a function of a parameter of the compensation signal, wherein the first quantum bit and the second quantum bit are any two quantum bits in the sub-chip to be measured;

[0023] A crosstalk matrix acquisition unit is used to acquire an XY crosstalk matrix based on the acquired XY crosstalk coefficients.

[0024] Based on the same inventive concept, the present invention also proposes a quantum computing measurement and control system, which utilizes the method for obtaining the XY crosstalk matrix of a quantum chip described in any one of the above-mentioned characteristic descriptions, or includes a device for obtaining the XY crosstalk matrix of a quantum chip described in the above-mentioned characteristic descriptions.

[0025] Based on the same inventive concept, the present invention also proposes a quantum computer, including the quantum computing measurement and control system described in the above feature description.

[0026] Based on the same inventive concept, the present invention also proposes a readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it can implement the method for obtaining the XY crosstalk matrix of a quantum chip described in any one of the above-mentioned feature descriptions.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The method for obtaining the XY crosstalk matrix of a quantum chip proposed in the present invention obtains the XY crosstalk coefficient between quantum bits in the sub-chip to be measured based on the experimental results of the crosstalk Ramsey experiment, wherein the crosstalk Ramsey experiment is to apply a compensation signal to the second quantum bit and perform a Ramsey experiment on the second quantum bit when there is XY crosstalk between the first quantum bit and the second quantum bit, and obtain the probability of the second quantum bit being in the first selected eigenstate as the compensation signal parameter changes, and the first quantum bit and the second quantum bit are any two quantum bits in the sub-chip to be measured. Based on the obtained XY crosstalk coefficient, the XY crosstalk matrix is ​​obtained. The scheme of the present application can effectively obtain the XY crosstalk matrix of the quantum chip, filling the gap in the prior art.

[0029] The device for acquiring the XY crosstalk matrix of a quantum chip, the quantum computing measurement and control system, the quantum computer, and the readable storage medium proposed in the present invention belong to the same inventive concept as the method for acquiring the XY crosstalk matrix of a quantum chip, and therefore have the same beneficial effects, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of a flow chart of a method for obtaining an XY crosstalk matrix of a quantum chip proposed in an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of a flow chart of how to obtain a crosstalk coefficient according to an embodiment of the present invention;

[0032] Figure 3 This is a timing diagram of a first quantum bit and a second quantum bit performing a crosstalk Ramsey experiment in an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of the structure of a device for acquiring the XY crosstalk matrix of a quantum chip proposed in another embodiment of the present invention. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention will be described in more detail below in conjunction with the schematic diagram. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0035] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In order to better understand the technical solution of this application, the following briefly describes the relevant technologies involved in this application:

[0038] The Ramsey experiment refers to the process of applying two π / 2 quantum logic gates (also called X / 2 gates) to a quantum bit, with the time interval between the two operations being τ, and applying a read pulse to the quantum bit after the second π / 2 quantum logic gate operation to obtain the excited state distribution P1(τ) of the quantum bit, and changing the time interval τ to obtain P1(τ). The result of a typical Ramsey experiment is that P1(τ) satisfies the mathematical model of exponential oscillation decay with the time interval τ as follows:

[0039]

[0040] In formula 1, A and B are fitting coefficients, T0 is the decoherence time of the quantum bit, and f d is the carrier frequency of the microwave pulse signal corresponding to the π / 2 quantum logic gate operation, f0 is the oscillation frequency of the quantum bit, and f0 is related to the real frequency f of the quantum bit. q , the carrier frequency of the π / 2 quantum logic gate operation satisfies:

[0041] f0(f d )=|f q -f d | (2)

[0042] To sum up and combine with formula 2, we can get: the result of the Ramsey experiment, that is, the oscillation frequency of the curve is equal to the difference between the carrier frequency of the quantum logic gate operation and the true frequency of the quantum bit. Therefore, in addition to being able to be used to obtain the decoherence time of the quantum bit, the Ramsey experiment can also accurately obtain the true frequency of the quantum bit at the same time.

[0043] Please refer to Figure 1 , an embodiment of the present invention proposes a method for obtaining an XY crosstalk matrix of a quantum chip, comprising:

[0044] S100: Based on the experimental results of the crosstalk Ramsey experiment, an XY crosstalk coefficient between quantum bits in the quantum chip to be measured is obtained, wherein the crosstalk Ramsey experiment is to apply a compensation signal to the second quantum bit and perform a Ramsey experiment on the second quantum bit when there is XY crosstalk between the first quantum bit and the second quantum bit, and obtain the probability that the second quantum bit is in a first selected eigenstate as the compensation signal parameter changes, and the first quantum bit and the second quantum bit are any two quantum bits in the quantum chip to be measured;

[0045] S200: Acquire an XY crosstalk matrix based on the acquired XY crosstalk coefficient.

[0046] The difference from the prior art is that the method for obtaining the XY crosstalk matrix of a quantum chip proposed in the embodiment of the present invention obtains the XY crosstalk coefficient between the quantum bits in the quantum chip to be measured based on the experimental results of the crosstalk Ramsey experiment, wherein the crosstalk Ramsey experiment is to apply a compensation signal to the second quantum bit and perform a Ramsey experiment on the second quantum bit when there is XY crosstalk between the first quantum bit and the second quantum bit, and obtain the probability of the second quantum bit being in the first selected eigenstate as the compensation signal parameter changes, and the first quantum bit and the second quantum bit are any two quantum bits in the quantum chip to be measured. Based on the obtained XY crosstalk coefficient, the XY crosstalk matrix is ​​obtained. The scheme of the present application can effectively obtain the XY crosstalk matrix of the quantum chip, filling the gap in the prior art.

[0047] It should be noted that for a quantum chip, the number of XY crosstalk matrices is determined by the frequency of the quantum state control signal. Assuming there are n quantum bits, the quantum state control signal of each quantum bit has only one frequency, that is, the quantum state control signal has n frequencies, then there are n XY crosstalk matrices. If the quantum state control signal of one quantum bit among the n quantum bits is composed of sub-signals of two frequencies, then there are n+1 XY crosstalk matrices. That is, the number of XY crosstalk matrices is equal to the number of frequencies of the quantum state control signal. In this embodiment, the parameters of the compensation signal include amplitude, phase, frequency, and pulse width. The XY crosstalk coefficient is used to represent the size of the XY crosstalk between any two quantum bits in the sub-chip to be measured.

[0048] In this embodiment, we take a quantum chip including three quantum bits as an example to illustrate the XY crosstalk matrix. Assuming that the three quantum bits of the quantum chip are Q1, Q2, and Q3, the structure of the XY crosstalk matrix of the quantum chip can be represented by the following matrix.

[0049]

[0050] The elements in the first row and first column of the matrix are the XY crosstalk coefficient of Q1 to Q1. Since there is no XY crosstalk influence on itself, the XY crosstalk coefficient is 1. The elements in the first row and second column are the XY crosstalk coefficient of Q1 to Q2, the elements in the first row and third column are the XY crosstalk coefficient of Q1 to Q3, the elements in the second row and first column are the XY crosstalk coefficient of Q2 to Q1, the elements in the second row and second column are the XY crosstalk coefficient of Q2 to Q2, the elements in the second row and third column are the XY crosstalk coefficient of Q2 to Q3, the elements in the third row and first column are the XY crosstalk coefficient of Q3 to Q1, the elements in the third row and second column are the XY crosstalk coefficient of Q3 to Q2, and the elements in the third row and third column are the XY crosstalk coefficient of Q3 to Q3.

[0051] Specifically, please refer to Figure 2 , Figure 2 The process steps for obtaining the crosstalk coefficient proposed in the embodiment of the present invention are as follows. In this embodiment, the XY crosstalk coefficient can be obtained by:

[0052] S102: When the first quantum bit has an XY crosstalk effect on the second quantum bit, applying a compensation signal to the second quantum bit and performing a Ramsey experiment on the second quantum bit;

[0053] S104: according to the experimental result of the Ramsey experiment, obtaining a first change of the probability that the second quantum bit is in the first selected eigenstate with the parameter of the compensation signal;

[0054] S106: Obtain an XY crosstalk coefficient of the first quantum bit to the second quantum bit based on the first change condition.

[0055] It should be noted that, in this embodiment, we apply the compensation signal to the quantum state control line of the second quantum bit between the two X / 2 gates in the Ramsey experiment.

[0056] The solution for obtaining the XY crosstalk coefficient of the first quantum bit to the second quantum bit given in this embodiment can be understood by those skilled in the art that the XY crosstalk coefficients of all quantum bits in the sub-chip to be measured can be obtained using this solution.

[0057] Specifically, in this embodiment, a quantum state control signal is applied to the quantum state control line of the first quantum bit so that the first quantum bit generates XY crosstalk on the second quantum bit, and the quantum state control signal applied to the quantum state control line of the first quantum bit is aligned with the compensation signal in timing. It should be noted that the timing diagram of the first quantum bit and the second quantum bit in the crosstalk Ramsey experiment can be referred to Figure 3 .

[0058] Specifically, in this embodiment, obtaining the XY crosstalk coefficient of the first qubit to the second qubit based on the first change situation includes:

[0059] Based on the first change, obtaining the amplitude of the compensation signal corresponding to the extreme point of the probability that the second quantum bit is in the first selected eigenstate is a first value;

[0060] The XY crosstalk coefficient of the first quantum bit to the second quantum bit is obtained based on the ratio of the first numerical value to the second numerical value, where the second numerical value is the amplitude of the quantum state control signal applied to the first quantum bit.

[0061] Specifically, in this embodiment, the frequency of the compensation signal is the same as the frequency of the quantum state control signal applied to the first quantum bit, and the pulse width of the compensation signal is the same as the pulse width of the quantum state control signal applied to the first quantum bit.

[0062] It can be seen from the description in the above background technology that in a quantum chip, if the influence of XY crosstalk is ignored and no treatment is performed, serious errors will occur in quantum computing tasks. We can use the XY crosstalk matrix obtained by the solution of this application to eliminate the problems caused by XY crosstalk, which can reduce the probability of errors when the quantum computer performs quantum computing tasks. Specifically, in this embodiment, we solve the XY crosstalk through the following solution:

[0063] Obtaining an XY crosstalk matrix of the sub-chip to be measured, wherein the XY crosstalk matrix is ​​composed of a plurality of XY crosstalk coefficients;

[0064] Obtaining an XY crosstalk inverse matrix based on the XY crosstalk matrix;

[0065] The XY crosstalk inverse matrix is ​​used to update the quantum state control signal of the quantum bit in the sub-chip to be measured.

[0066] Those skilled in the art can understand that the XY crosstalk inverse matrix is ​​obtained by inverting the XY crosstalk matrix.

[0067] From the previous analysis, it can be seen that the number of XY crosstalk matrices of the sub-chip to be measured is equal to the number of frequencies of the quantum state control signal. Generally, we refer to the several signals constituting the quantum state control signal of a certain quantum bit as sub-signals. Specifically, in this embodiment, the quantum state control signal of the quantum bit in the sub-chip to be measured includes several sub-signals with different frequencies, and each of the sub-signals corresponds to an XY crosstalk matrix.

[0068] Since each sub-signal corresponds to an XY crosstalk matrix, we can use the XY crosstalk matrix to obtain the updated signal corresponding to each sub-signal, and then merge all the sub-signals into a complete updated quantum state control signal. Specifically, in this embodiment, the use of the XY crosstalk inverse matrix to update the quantum state control signal of the quantum bit in the sub-chip to be measured includes:

[0069] Obtain the XY crosstalk inverse matrix corresponding to each sub-signal;

[0070] The quantum state control signal of the quantum bit in the sub-chip to be measured is updated based on the sub-signal and the corresponding XY crosstalk inverse matrix.

[0071] Specifically, in this embodiment, the quantum state control signal of the quantum bit in the sub-chip to be measured is updated by the following formula:

[0072]

[0073] Among them, XY n is the quantum state control signal after the nth quantum bit in the sub-chip to be measured is updated, M(ω j ) -1 [n][j] is the matrix M(ω j ) -1 The element in the nth row and jth column, M(ω j ) -1 is the sub-signal U j The corresponding XY crosstalk inverse matrix.

[0074] Specifically, in this embodiment, the obtaining of an XY crosstalk inverse matrix based on the XY crosstalk matrix includes:

[0075] The XY crosstalk inverse matrix is ​​obtained by performing an inversion operation on the XY crosstalk matrix.

[0076] Specifically, in this embodiment, the crosstalk coefficient is obtained through the experimental results of a crosstalk Ramsey experiment. The crosstalk Ramsey experiment is to apply a compensation signal to the second quantum bit and perform a Ramsey experiment on the second quantum bit when there is XY crosstalk between the first quantum bit and the second quantum bit, so as to obtain the probability that the second quantum bit is in a first selected eigenstate as the compensation signal parameters change. The first quantum bit and the second quantum bit are any two quantum bits in the sub-chip to be measured.

[0077] Still taking the above-mentioned quantum chip containing three quantum bits Q1, Q2, and Q3 as an example, we briefly explain how to use the XY crosstalk inverse matrix to update the quantum state control signal. Assume that the quantum state control signals of quantum bits Q1, Q2, and Q3 each have only one frequency, the frequency of the quantum state control signal of quantum bit Q1 is ω1, the frequency of the quantum state control signal of quantum bit Q2 is ω2, and the frequency of the quantum state control signal of quantum bit Q3 is ω3. We can use the following formula to obtain the updated quantum state control signal.

[0078]

[0079] in, is the updated quantum state control signal of quantum bit Q1, is the updated quantum state control signal of quantum bit Q2, is the updated quantum state control signal of quantum bit Q3, X1 is the initial quantum state control signal of quantum bit Q1, X2 is the initial quantum state control signal of quantum bit Q2, X3 is the initial quantum state control signal of quantum bit Q3, M(ω1) -1 is the inverse XY crosstalk matrix of quantum bit Q1, M(ω2) -1 is the inverse XY crosstalk matrix of quantum bit Q2, M(ω3) -1 is the inverse XY crosstalk matrix of quantum bit Q3.

[0080] It should be noted that in this embodiment, the quantum state control signal of each quantum bit has only one sub-signal. Assume that the quantum bit Q1 has two sub-signals X 11 and X 12 , the frequencies of these two sub-signals are ω 11 and ω 12 , then the first term on the right side of Formula 4 can be expressed as:

[0081]

[0082] When the quantum bit Q1 has more sub-signals or other quantum bits have more sub-signals, they can be obtained according to this idea, which will not be elaborated here.

[0083] Based on the same invention concept, please refer to Figure 4 The embodiment of the present invention further provides a device for obtaining an XY crosstalk matrix of a quantum chip, comprising:

[0084] A crosstalk coefficient acquisition unit 100 is used to acquire an XY crosstalk coefficient between quantum bits in a sub-chip to be measured based on an experimental result of a crosstalk Ramsey experiment, wherein the crosstalk Ramsey experiment is to apply a compensation signal to a second quantum bit and perform a Ramsey experiment on the second quantum bit when an XY crosstalk exists between a first quantum bit and a second quantum bit, and acquire a probability that the second quantum bit is in a first selected eigenstate as a function of a parameter of the compensation signal, wherein the first quantum bit and the second quantum bit are any two quantum bits in the sub-chip to be measured;

[0085] The crosstalk matrix acquisition unit 200 is configured to acquire an XY crosstalk matrix based on the acquired XY crosstalk coefficients.

[0086] It can be understood that the crosstalk coefficient acquisition unit 100 and the crosstalk matrix acquisition unit 200 can be combined in one device, or any one of the modules can be split into multiple sub-modules, or at least part of the functions of one or more modules in the crosstalk coefficient acquisition unit 100 and the crosstalk matrix acquisition unit 200 can be combined with at least part of the functions of other modules and implemented in one functional module. According to an embodiment of the present invention, at least one of the crosstalk coefficient acquisition unit 100 and the crosstalk matrix acquisition unit 200 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented in hardware or firmware in any other reasonable way of integrating or packaging the circuit, or in a proper combination of software, hardware and firmware. Alternatively, at least one of the crosstalk coefficient acquisition unit 100 and the crosstalk matrix acquisition unit 200 can be at least partially implemented as a computer program module, and when the program is run by a computer, the function of the corresponding module can be executed.

[0087] Based on the same inventive concept, an embodiment of the present invention further proposes a quantum computing measurement and control system, which utilizes the method for obtaining the XY crosstalk matrix of a quantum chip described in any one of the above-mentioned characteristic descriptions, or includes a device for obtaining the XY crosstalk matrix of a quantum chip described in the above-mentioned characteristic descriptions.

[0088] Based on the same inventive concept, an embodiment of the present invention also proposes a quantum computer, including the quantum computing measurement and control system described in the above feature description.

[0089] Based on the same inventive concept, an embodiment of the present invention further proposes a readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for obtaining the XY crosstalk matrix of a quantum chip described in any one of the above-mentioned feature descriptions can be implemented.

[0090] The readable storage medium can be a tangible device that can keep and store the instructions used by the instruction execution device, such as but not limited to an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device or any suitable combination of the above. The more specific example (non-exhaustive list) of the readable storage medium includes: 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), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a convex structure in a groove on which instructions are stored, and any suitable combination of the above. The computer program described here can be downloaded from the readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device through a network, such as the Internet, a local area network, a wide area network and / or a wireless network. The network can include copper transmission cables, optical fiber transmission, wireless transmission, routers, firewalls, switches, gateway computers and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer program from the network and forwards the computer program for storage in a readable storage medium in each computing / processing device. The computer program for performing the operation of the present invention may be an assembly instruction, an instruction set architecture (ISA) instruction, a machine instruction, a machine-dependent instruction, a microcode, a firmware instruction, a state setting data, or a source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as "C" language or similar programming languages. The computer program may be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet). In some embodiments, by utilizing the state information of a computer program to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute computer-readable program instructions to implement various aspects of the present invention.

[0091] Here, various aspects of the present invention are described with reference to the flowchart and / or block diagram of the method, system and computer program product according to the embodiment of the present invention. It should be understood that each square frame of the flowchart and / or block diagram and the combination of the square frames in the flowchart and / or block diagram can be realized by a computer program. These computer programs can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device, so as to produce a machine, so that these programs, when executed by the processor of a computer or other programmable data processing device, produce a device for realizing the function / action specified in one or more square frames in the flowchart and / or block diagram. These computer programs can also be stored in a readable storage medium, and these computer programs make the computer, programmable data processing device and / or other equipment work in a specific way, so that the readable storage medium storing the computer program includes a manufactured product, which includes instructions for realizing various aspects of the function / action specified in one or more square frames in the flowchart and / or block diagram.

[0092] The computer program may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operational steps are executed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the computer program executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example" or "specific example" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0094] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A method for obtaining a quantum chip XY crosstalk matrix, characterized in that: include: Based on the experimental results of the crosstalk Ramsey experiment, an XY crosstalk coefficient between quantum bits in the quantum chip to be measured is obtained, wherein the crosstalk Ramsey experiment is to apply a compensation signal to the second quantum bit and perform a Ramsey experiment on the second quantum bit when there is XY crosstalk between the first quantum bit and the second quantum bit, and obtain the probability of the second quantum bit being in a first selected eigenstate as the compensation signal parameter changes, and the first quantum bit and the second quantum bit are any two quantum bits in the quantum chip to be measured; Based on the obtained XY crosstalk coefficients, an XY crosstalk matrix is ​​obtained.

2. The method according to claim 1, characterized in that The XY crosstalk coefficient is obtained by: When the first qubit has an XY crosstalk effect on the second qubit, applying a compensation signal to the second qubit and performing a Ramsey experiment on the second qubit; According to the experimental result of the Ramsey experiment, obtaining a first change in the probability of the second quantum bit being in the first selected eigenstate as a function of the parameter of the compensation signal; An XY crosstalk coefficient of the first quantum bit to the second quantum bit is obtained based on the first change.

3. The method according to claim 2, characterized in that The compensation signal is applied to the quantum state control line of the second quantum bit between the two X / 2 gates in the Ramsey experiment.

4. The method according to claim 3, characterized in that A quantum state control signal is applied to the quantum state control line of the first quantum bit so that the first quantum bit generates XY crosstalk on the second quantum bit, and the quantum state control signal applied to the quantum state control line of the first quantum bit is aligned in timing with the compensation signal.

5. The method according to claim 2, characterized in that The obtaining, based on the first change, an XY crosstalk coefficient of the first quantum bit to the second quantum bit includes: Based on the first change, obtaining the amplitude of the compensation signal corresponding to the extreme point of the probability that the second quantum bit is in the first selected eigenstate is a first value; The XY crosstalk coefficient of the first quantum bit to the second quantum bit is obtained based on the ratio of the first numerical value to the second numerical value, where the second numerical value is the amplitude of the quantum state control signal applied to the first quantum bit.

6. The method according to claim 1, characterized in that The parameters of the compensation signal include amplitude, phase, frequency, and pulse width.

7. The method according to claim 6, characterized in that The frequency of the compensation signal is the same as the frequency of the quantum state control signal applied to the first quantum bit, and the pulse width of the compensation signal is the same as the pulse width of the quantum state control signal applied to the first quantum bit.

8. A device for obtaining a quantum chip XY crosstalk matrix, characterized in that: include: A crosstalk coefficient acquisition unit, used for acquiring an XY crosstalk coefficient between quantum bits in the sub-chip to be measured based on an experimental result of a crosstalk Ramsey experiment, wherein the crosstalk Ramsey experiment is to apply a compensation signal to a second quantum bit and perform a Ramsey experiment on the second quantum bit when an XY crosstalk exists between a first quantum bit and a second quantum bit, and to acquire a probability that the second quantum bit is in a first selected eigenstate as a function of a parameter of the compensation signal, wherein the first quantum bit and the second quantum bit are any two quantum bits in the sub-chip to be measured; A crosstalk matrix acquisition unit is used to acquire an XY crosstalk matrix based on the acquired XY crosstalk coefficients.

9. A quantum computing measurement and control system, characterized in that: A method for obtaining the quantum chip XY crosstalk matrix according to any one of claims 1 to 7, or a device for obtaining the quantum chip XY crosstalk matrix according to claim 8.

10. A quantum computer, characterized in that: Including the quantum computing measurement and control system as described in claim 9.

11. A readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it can implement the method for obtaining the XY crosstalk matrix of a quantum chip according to any one of claims 1 to 7.

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