Method and device for eliminating crosstalk between quantum bits in superconducting quantum chip

Abstract

The invention provides a method and device for eliminating crosstalk between quantum bits in a superconducting quantum chip, electronic equipment and a non-instantaneous computer readable storage medium, and the method comprises the steps: determining a topological structure corresponding to an excessive quantum chip in response to an elimination instruction of the crosstalk between the quantum bits in the superconducting quantum chip; mapping the topological structure into an undirected graph; classifying vertexes in the undirected graph to enable quantum bits corresponding to two ends of any edge in the undirected graph to belong to different classifications; decomposing the undirected graph into a plurality of sub-graphs according to the classification of the vertexes until the obtained sub-graphs only comprise one classification; and applying a control pulse to the quantum bits corresponding to the edges connected with the different sub-graphs, and eliminating crosstalk between the quantum bits. According to the embodiment of the invention, crosstalk caused by interaction between quantum bits is eliminated.

Description

Technical Field

[0001] The present application relates to the field of quantum chips, and more specifically, to a method and device for eliminating crosstalk between quantum bits in a superconducting quantum chip, an electronic device, and a non-transient computer-readable storage medium. Background Art

[0002] Quantum computers have the ability to surpass classical computers in solving certain problems, but the realization of this ability requires the performance of quantum chips to reach a certain level. Superconducting quantum chips are currently the most mature and popular quantum computer hardware solution. Using superconducting quantum computers to implement valuable quantum algorithms requires overcoming the noise on superconducting quantum bits and crosstalk between bits.

[0003] Most of the existing solutions to the crosstalk problem are based on hardware, by designing new bits or chip structures to solve this problem. The advantage of this approach is that it can solve the crosstalk problem from the bottom up, without the need for subsequent operations or resource consumption, but the new hardware structure is usually much more complex than the existing design, and puts higher requirements on chip design and preparation technology. The current level of superconducting hardware processing is still difficult to meet such requirements.

[0004] At present, dynamic decoupling can be used to apply control pulses to quantum bits to equivalently offset the interaction between the bits and the surrounding environment, thereby protecting the quantum bits from environmental noise, but this method is only applicable to the arrangement of quantum bits in a square grid. In fact, there are many other arrangements of existing superconducting quantum chips, such as regular hexagonal arrangement, star arrangement or cross arrangement. At present, there is no technical solution to eliminate the crosstalk between bits in these quantum bit arrangements. Summary of the invention

[0005] The present application aims to propose a method and device for eliminating crosstalk between quantum bits in a superconducting quantum chip, an electronic device, and a non-transient computer-readable storage medium to solve the crosstalk between bits in a superconducting quantum chip.

[0006] According to one aspect of the present application, a method for eliminating crosstalk between quantum bits in a superconducting quantum chip is proposed, comprising: in response to an instruction for eliminating crosstalk between quantum bits in a superconducting quantum chip, determining a topological structure corresponding to the superconducting quantum chip; mapping the topological structure into an undirected graph; classifying the vertices in the undirected graph so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different classifications; decomposing the undirected graph into a plurality of subgraphs according to the classification of the vertices so that each obtained subgraph includes only one classification; applying control pulses to the quantum bits corresponding to the edges connecting different subgraphs to eliminate the crosstalk between the quantum bits.

[0007] According to some embodiments, determining a topological structure corresponding to the superconducting quantum chip includes: determining the topological structure based on a quantum bit arrangement and interactions between quantum bits in the superconducting quantum chip.

[0008] According to some embodiments, mapping the topological structure into an undirected graph includes: mapping quantum bits in the superconducting quantum chip into vertices in the undirected graph; and mapping interactions between quantum bits in the superconducting quantum chip into edges in the undirected graph.

[0009] According to some embodiments, the vertices in the undirected graph are classified so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different categories, including: coloring the vertices in the undirected graph, wherein the quantum bits at the two ends of any edge in the undirected graph have different colors.

[0010] According to some embodiments, before decomposing the undirected graph into multiple subgraphs according to the classification of vertices so that each obtained subgraph includes only one classification, the method further includes: determining a coloring number based on the colored mapping graph.

[0011] According to some embodiments, the undirected graph is decomposed into multiple subgraphs according to the classification of vertices, so that each obtained subgraph includes only one classification, including: decomposing the undirected graph into two subgraphs according to the classification color of the quantum bits to obtain a first subgraph and a second subgraph; using a preset decoupling rule to eliminate the connection between the first subgraph and the second subgraph; if the coloring number of the first subgraph and / or the second subgraph is greater than 1, continue to decompose the first subgraph and / or the second subgraph, and use the decoupling rule to decouple the decomposed subgraphs of the first subgraph and / or the second subgraph until the coloring number of the obtained subgraphs of the first subgraph and / or the second subgraph is equal to 1.

[0012] According to some embodiments, the connection between the first subgraph and the second subgraph is eliminated using a preset decoupling rule, including: performing a first free evolution on the quantum bits belonging to the first subgraph or the second subgraph among the quantum bits connecting the first subgraph and the second subgraph; applying a Pauli-X operator to the quantum bits after the first free evolution; performing a second free evolution on the quantum bits after the action; and applying a Pauli-X operator to the quantum bits after the second free evolution.

[0013] According to one aspect of the present application, a device for eliminating crosstalk between quantum bits in a superconducting quantum chip is proposed, comprising: a topology determination unit, for determining a topology corresponding to the superconducting quantum chip in response to an instruction for eliminating crosstalk between quantum bits in the superconducting quantum chip; a mapping graph generation unit, for mapping the topology into an undirected graph to obtain a corresponding mapping graph; a quantum bit classification unit, for classifying vertices in the undirected graph so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different classifications; a mapping graph decomposition unit, for decomposing the undirected graph into a plurality of subgraphs according to the classification of the vertices, until the obtained subgraph includes only one classification; and a crosstalk elimination unit, for applying control pulses to the quantum bits corresponding to the edges connecting different subgraphs to eliminate crosstalk between quantum bits.

[0014] According to one aspect of the present application, an electronic device is proposed, comprising one or more processing units; a storage unit for storing one or more programs; when the one or more programs are executed by the one or more processing units, the one or more processing units implement the elimination method described in any of the previous embodiments.

[0015] According to one aspect of the present application, a non-transitory computer-readable storage medium is provided, on which computer-readable instructions are stored. When the instructions are executed by a processor, the processor executes the elimination method described in any of the previous embodiments.

[0016] According to an embodiment of the present application, first, the bit arrangement in the superconducting quantum chip is mapped into an undirected graph, and then the obtained undirected graph is decomposed until the obtained mapping subgraph includes only one classification, so as to decouple the interaction between quantum bits, thereby eliminating the crosstalk caused by the interaction between quantum bits.

[0017] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. By describing the exemplary embodiments in detail with reference to the drawings, the above and other objectives, features and advantages of the present application will become more apparent.

[0019] Figure 1 A flow chart of a method for eliminating crosstalk between quantum bits in a superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0020] Figure 2a A mapping diagram of a superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0021] Figure 2b A mapping diagram of another superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0022] Figure 3a A flow chart of a method for eliminating crosstalk between quantum bits in another superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0023] Figure 3b A schematic diagram of the decoupling process of crosstalk between quantum bits in another superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0024] Figure 4 A schematic diagram of a decoupling process with a coloring number of 5 according to an exemplary embodiment of the present application is shown.

[0025] Figure 5a A schematic diagram of the topological structure of a superconducting quantum chip is shown.

[0026] Figure 5b A mapping diagram of a superconducting quantum chip of an exemplary embodiment of the present application is shown.

[0027] Figure 6a A schematic diagram of the topological structure of another superconducting quantum chip is shown.

[0028] Figure 6b A mapping diagram of another superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0029] Figure 7 A device for eliminating crosstalk between quantum bits in a superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0030] Figure 8 An electronic device according to an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. In the figures, the same figures show the same or similar parts, and thus their repeated description will be omitted.

[0032] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other modes, components, materials, devices or operations may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0033] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0034] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0035] The specific embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0036] Figure 1 A flow chart of a method for eliminating crosstalk between quantum bits in a superconducting quantum chip according to an exemplary embodiment of the present application is shown. Figure 1 The elimination method shown includes steps S101, S103, S105, S107 and S109.

[0037] In step S101, in response to an instruction to eliminate crosstalk between quantum bits in a superconducting quantum chip, a topological structure corresponding to the superconducting quantum chip is determined.

[0038] The topological structure of a superconducting quantum chip consists of two parts: the first part is the location of the bits in the superconducting quantum chip, and the second part is the interaction between the bits. According to an embodiment of the present application, the topological structure is determined based on the arrangement of quantum bits in the superconducting quantum chip and the interaction between quantum bits.

[0039] In step S103, the topological structure is mapped into an undirected graph.

[0040] According to an embodiment of the present application, when a superconducting quantum chip is mapped into an undirected graph according to the topological structure of the superconducting quantum chip, each bit corresponds to a vertex on the graph, and the interaction between two bits corresponds to an edge on the graph connecting the corresponding two vertices.

[0041] Since superconducting bits interact with each other in pairs, each edge will only connect two vertices, and there will not be three vertices, so the topological structure of the chip can always be mapped into a graph. According to this mapping rule, if each bit in the superconducting quantum chip interacts with other bits, then all vertices on the mapped undirected graph are connected to other vertices by edges, and there are no free vertices; if there are isolated bits in the superconducting quantum chip that do not interact with any other bits due to problems in the preparation process, then this isolated bit is useless when implementing quantum algorithms, and it is also a free vertex in the final mapped undirected graph.

[0042] In step S105, the vertices in the undirected graph are classified so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different categories.

[0043] According to an embodiment of the present application, in step S105, the vertices in the undirected graph are colored, wherein the quantum bits at both ends of any edge in the undirected graph are colored with different colors.

[0044] In a specific embodiment, after the topological structure of the superconducting quantum chip is mapped into an undirected graph, the undirected graph is colored. In some embodiments, the coloring rule is to assign a color to each vertex, and require that the vertices at both ends of an edge are assigned different colors. It should be noted that vertices that are not on the same edge can be assigned the same color.

[0045] In step S107, the undirected graph is decomposed into multiple subgraphs according to the classification of vertices, so that each subgraph includes only one classification.

[0046] According to an embodiment of the present application, before step S107, it is also necessary to determine the coloring number based on the colored undirected graph. For a given graph, the minimum number of colors required is usually called the coloring number. For any graph, for example, if there are cross-interacting quantum bits, the value of the coloring number may be very large. However, for superconducting quantum chips involved in planarization, since the quantum bits are arranged on a two-dimensional plane, there is no cross-interaction between the bits. According to the four-color theorem, the coloring number is at most 4.

[0047] like Figure 2a The undirected graph shown is of a superconducting quantum chip arranged in a square grid, with only interactions between nearest neighbor quantum bits. The two vertices of each edge in the undirected graph are given different colors and represented by a circle and a square respectively. Figure 2aThe coloring number of the undirected graph shown is 2, represented by yellow and blue respectively.

[0048] like Figure 2b The undirected graph of a superconducting quantum chip with cross-interactions between quantum bits is shown. The quantum bits have two types of interactions: nearest neighbor and next nearest neighbor. The coloring number for this case is 4, represented by yellow, blue, green, and purple, and represented by circles, squares, ellipses, and hexagons, respectively.

[0049] In some embodiments, in step S107, the undirected graph is decomposed into two subgraphs according to the coloring number to obtain a first subgraph and a second subgraph; the two subgraphs are decoupled using a preset decoupling rule; if the coloring number in the first subgraph and / or the second subgraph is greater than 1, the first subgraph and / or the second subgraph continues to be decomposed, and the decoupling rule is used to decouple the decomposed subgraphs of the first subgraph and / or the second subgraph until the coloring number of the obtained subgraphs of the first subgraph and / or the second subgraph is equal to 1, so as to eliminate the connection between the subgraphs.

[0050] According to an embodiment of the present application, when a preset decoupling rule is used to eliminate the connection between the first subgraph and the second subgraph, first, the quantum bits belonging to the first or second subgraph among the quantum bits connecting the first subgraph and the second subgraph are subjected to a first free evolution; then, the Pauli-X operator is applied to the quantum bits after the first free evolution, and the quantum bits after the action are subjected to a second free evolution; finally, the Pauli-X operator is applied to the quantum bits after the second free evolution.

[0051] In a specific embodiment, the interaction between the bits is usually turned on and off by a coupler. When the interaction between the qubits is turned off by the coupler, there is usually a small amount of residual between the two qubits due to system errors. The interaction of is the Pauli-Z operator acting on the kth bit, J k,l is the interaction strength between the two qubits. These residual interactions lead to crosstalk between qubits.

[0052] In the embodiment of the present application, it is assumed that the interaction causing the crosstalk between two bits is as shown in formula (1).

[0053]

[0054] Among them, the two related quantum bits are assigned two different colors respectively.

[0055] In step S109, control pulses are applied to the qubits corresponding to the edges connecting different subgraphs to eliminate crosstalk between qubits.

[0056] In order to eliminate the interaction between the quantum bits in the two subgraphs, in some embodiments, the decoupling sequence used is as shown in formula (2), that is, first, the two quantum bits are allowed to evolve freely for a sufficiently small time δ (for example, tens to hundreds of nanoseconds), and then a Pauli-X operator is applied to the kth bit. Then, the two quantum bits are allowed to evolve freely for a small time δ (for example, tens to hundreds of nanoseconds), and finally a Pauli-X operator is applied to the kth bit.

[0057]

[0058] The whole evolution process is shown in formula (3).

[0059]

[0060] According to formula (3), the crosstalk between two quantum bits is It is eliminated during the decoupling process.

[0061] The method of eliminating qubit crosstalk shown in formula (3) is to eliminate the crosstalk between qubits that interact with each other. According to the embodiment of the present application, the decoupling sequence shown in formula (4) can be used to eliminate the crosstalk between qubits representing multiple qubits of the same color between mapping subgraphs, so as to eliminate the crosstalk of qubits between mapping subgraphs. That is, the qubits between mapping subgraphs that interact with each other are decoupled at one time. Figure 4 The decoupling sequence required for the decoupling process shown includes two decoupling pulses, such as Figure 4 shown.

[0062] D (m,n) =[δ,X (m) δX (m) ], (4)

[0063] Among them, m and n are two color labels, X (m) is the Pauli-X operator acting on all bits of the mth color.

[0064] Because there is no interaction between qubits of the same color, the Pauli-X operator only needs to act on the m-th color bit connecting the two colors. In a specific embodiment, after determining the qubit to which the decoupling pulse needs to be applied, an arbitrary waveform amplifier is used to generate a control pulse in the X direction according to the frequency of the corresponding qubit, and the control pulse is maintained for a certain time (for example, 20 to 40 nanoseconds) according to the intensity of the control pulse. After this decoupling effect, the interaction between the qubits of the two colors between the mapping subgraphs is eliminated.

[0065] For example, the mapping graph is decomposed to obtain subgraphs A and B, wherein there is interaction between qubit a1 in subgraph A and b1 in subgraph B, and there is interaction between qubit a2 in subgraph A and b2 in subgraph B. According to an embodiment of the present application, the method shown in formula (3) can be used to act on qubits a1 and a2 to eliminate crosstalk between qubits in the mapping subgraphs.

[0066] according to Figure 1 In the embodiment shown, first, the bit arrangement in the superconducting quantum chip is mapped into an undirected graph, and then the obtained undirected graph is decomposed based on the coloring number to decouple the interaction between quantum bits, thereby eliminating the crosstalk caused by the interaction between quantum bits.

[0067] According to the embodiments of the present application, it can be used to solve the crosstalk between quantum bits in a quantum chip of any topological structure, and the complexity of control is only related to the coloring number of the graph and does not increase with the increase in chip size.

[0068] Figure 3a A flow chart of a method for eliminating crosstalk between quantum bits in another superconducting quantum chip according to an exemplary embodiment of the present application is shown. Figure 3b A schematic diagram of the decoupling process of crosstalk between quantum bits in another superconducting quantum chip according to an exemplary embodiment of the present application is shown.

[0069] like Figure 3a and 3b As shown, in step S301, a topological structure T corresponding to a superconducting quantum chip is determined according to the quantum bit arrangement of a given superconducting quantum chip and the interaction between quantum bits.

[0070] In step S303, the topological structure of the super quantum chip is mapped into a corresponding undirected graph.

[0071] For example, the topological structure T of the superquantum chip is mapped into the corresponding undirected graph G(V, E).

[0072] In this mapping, the quantum bits in the topological structure correspond to the vertices V in the graph, and the interactions between the quantum bits correspond to the edges E in the graph.

[0073] In step S305, the vertices in the undirected graph (representing quantum bits) are colored, and the coloring number of the graph is determined.

[0074] It should be noted here that since the vertices in the undirected graph correspond to the quantum bits in the superconducting quantum chip, in this application, for ease of understanding, the vertices in the undirected graph are replaced by quantum bits.

[0075] For example, the vertices (representing quantum bits) in the undirected graph G(V, E) are colored and the coloring number C of the graph is determined.

[0076] According to an embodiment of the present application, when coloring, it is required that the vertices (representing quantum bits) at both ends of an edge cannot be colored with the same color.

[0077] In step S307, the undirected graph is divided into two subgraphs according to the coloring number.

[0078] For example, the graph G is divided into two subgraphs G according to the coloring number C 1 and G 2 , where G 1 There are C / 2 (round down if not an integer) colors of quantum bits in the .

[0079] If C is even, then G 1 and G 2 Each contains bits corresponding to C / 2 colors; if C is an odd number, then G 2 The colors contained in G 1 More 1 or G 1 The colors contained in G 2 You can choose one of the methods, there is no restriction.

[0080] In step S309, the interactions between subgraphs are eliminated using a preset decoupling rule.

[0081] For example, determine the connection between two subgraphs G 1 and G 2 The quantum bits in the subgraph G 1 Apply a decoupling sequence to the relevant qubits Subgraph G 1 and G 2 According to some embodiments, it is also possible to eliminate the interaction between the subgraph G 2 Apply a decoupling sequence to the relevant qubits No restrictions are imposed here.

[0082] According to an embodiment of the present application, the decoupling sequence is determined according to formula (4):

[0083] In step S311, the subgraphs are further decomposed, and the interactions between the decomposed subgraphs are eliminated until the decomposed subgraphs contain only quantum bits of one color.

[0084] Taking G1 as an example, first, G 1 Further divided into two subgraphs G 1,1 and G 1,2 , then, determine the connection between the two subgraphs G 1,1 and G1,2 The quantum bits in the subgraph G 1,1 Apply a decoupling sequence to the relevant physical bits Subgraph G 1,1 and G 1,2 The interactions between them are eliminated.

[0085] According to some embodiments, it is also possible to 1,2 Apply a decoupling sequence to the relevant qubits No restrictions are imposed here.

[0086] In the G 1 When decomposing, if G 1 The number of colors contained is even, then G 1,1 and G 1,2 Each contains half of the bits corresponding to the color; if G 1 If the number of colors contained in is an odd number, select G 1,2 The number of colors contained in G 1,1 Win 1 or choose G 1,1 The number of colors contained in G 1,2 There is no limit on the number of wins.

[0087] Similarly, first, G 2 Further divided into two subgraphs G 2,1 and G 2,2 , then, determine the connection between the two subgraphs G 2,1 and G 2,2 The quantum bits in the subgraph G 2,1 Apply a decoupling sequence to the relevant physical bits Subgraph G 2,2 The interactions between them are eliminated.

[0088] According to some embodiments, it is also possible to 2,2 Apply a decoupling sequence to the relevant qubits No restrictions are imposed here.

[0089] In the G 2 When decomposing, if G 2 If the number of colors contained in is even, then G 2,1 and G 2,2 Each contains half of the bits corresponding to the color; if G 2 If the number of colors contained in is odd, then G 2,2 The number of colors contained in G 2,1 More than 1, or G 2,1 The number of colors contained in G 2,2 There is no limit on the number of wins.

[0090] According to an embodiment of the present application, if the obtained subgraph G 1,1 , G 1,2 , G 2,1 and / or G 2,2 If the coloring number of is greater than 1, it is necessary to continue decomposing according to the method shown in step S311 and use the decoupling sequence shown in formula (4) to eliminate the interaction between subgraphs until the decomposed subgraph contains only quantum bits of one color.

[0091] Figure 4 A schematic diagram of a decoupling process with a coloring number of 5 according to an exemplary embodiment of the present application is shown. Figure 4 As shown, first decompose the mapping graph into subgraphs and in, Indicates Figure 1 , including 2 quantum bits; Subgraph 2 includes three qubits and is represented by the decoupling sequence D shown in formula (4). 1 eliminate and The interaction of the quantum bits in . Then, the subgraph Further decomposition, we get and Pair of subgraphs Further decomposition, we get and According to the decoupling sequence D shown in formula (4) 2 Eliminate and The interactions of the qubits in the and Then, we continue to Continue decomposing until the decomposed subgraph contains only quantum bits of one color.

[0092] Figure 5a A schematic diagram of the topological structure of a superconducting quantum chip is shown. Figure 5a As shown in the figure, each multiplication sign represents a quantum bit, and the box between the two multiplication signs represents the coupler that controls the interaction between the bits. Figure 5a There are a total of 54 bits in the superconducting quantum chip shown.

[0093] Figure 5b The undirected graph G corresponding to the superconducting quantum chip is shown. 2 ,like Figure 5b As shown, the coloring number of the undirected graph is 2, and the hollow circles and the solid circles correspond to two colors respectively. 2 When decoupling, you only need to change G 2Split into two sub-graphs and The first sub-graph contains the bits corresponding to the solid circles, while the second subgraph Therefore, as long as the decoupling pulse is applied to the bit corresponding to the solid circle, the interaction between all bits can be eliminated, and the required decoupling sequence is as shown in formula (5).

[0094]

[0095] Figure 6a Another schematic diagram of the topological structure of a superconducting quantum chip is shown. Figure 6a As shown, each circle represents a quantum bit, the number inside the circle represents the sequence number of the bit, and the diamonds between the circles represent couplers that control the interaction between the bits. There are a total of 130 bits in this superconducting quantum chip.

[0096] Figure 6b The undirected graph G corresponding to the superconducting quantum chip is shown. 2 ,like Figure 6b As shown, the undirected graph is a 2-color graph containing 130 vertices. Therefore, according to an embodiment of the present application, in the undirected graph G 2 When decoupling, you only need to change G 2 Split into two sub-graphs and Among them, the first sub-graph contains the bits corresponding to the solid circles, while the second subgraph Therefore, as long as the decoupling pulse is applied to the bit corresponding to the solid circle according to the decoupling sequence shown in formula (5), the interaction between all bits can be eliminated.

[0097] The above mainly introduces the embodiments of the present application from the perspective of the method. Those skilled in the art should easily appreciate that, in combination with the operations or steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Those skilled in the art can use different ways to implement the described functions for each specific operation or method, and such implementation should not be considered to be beyond the scope of the present application.

[0098] The following describes the device embodiments of the present application. For details not described in the device embodiments of the present application, reference can be made to the method embodiments of the present application.

[0099] Figure 7 A device for eliminating crosstalk between quantum bits in a superconducting quantum chip according to an exemplary embodiment of the present application is shown. Figure 7The elimination device shown includes a topology determination unit 701, an undirected graph generation unit 703, a qubit classification unit 705, an undirected graph decomposition unit 707 and a crosstalk elimination unit 709. The topology determination unit 701 is used to respond to the elimination instruction of the crosstalk between qubits in the superconducting quantum chip, and determine the topology corresponding to the superconducting quantum chip; the undirected graph generation unit 703 is used to map the topology into an undirected graph; the qubit classification unit 705 is used to classify the vertices in the undirected graph so that the qubits corresponding to the two ends of any edge in the undirected graph belong to different categories; the undirected graph decomposition unit 707 is used to decompose the undirected graph into multiple subgraphs according to the classification of the vertices, until the obtained subgraph includes only one classification. The crosstalk elimination unit 709 is used to apply control pulses to the qubits corresponding to the edges connecting different subgraphs to eliminate the crosstalk between the subgraphs.

[0100] Figure 8 An electronic device according to an exemplary embodiment of the present application is shown. Figure 8 The electronic device 200 according to this embodiment of the present application is described. Figure 8 The electronic device 200 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0101] like Figure 8 As shown, the electronic device 200 is in the form of a general computing device. The components of the electronic device 200 may include, but are not limited to: at least one processing unit 210, at least one storage unit 220, a bus 230 connecting different system components (including the storage unit 220 and the processing unit 210), a display unit 240, etc.

[0102] The storage unit stores program codes, which can be executed by the processing unit 210, so that the processing unit 210 executes the methods described in this specification according to various exemplary embodiments of the present application. For example, the processing unit 210 can execute the following: Figure 1 The method shown in .

[0103] The storage unit 220 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 2201 and / or a cache memory unit 2202 , and may further include a read-only memory unit (ROM) 2203 .

[0104] The storage unit 220 may also include a program / utility 2204 having a set (at least one) of program modules 2205, such program modules 2205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0105] Bus 230 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0106] The electronic device 200 may also communicate with one or more external devices 300 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 200, and / or communicate with any device that enables the electronic device 200 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 250. Furthermore, the electronic device 200 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 260. The network adapter 260 may communicate with other modules of the electronic device 200 via the bus 230. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 200, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0107] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software or by combining software with necessary hardware. The technical solution according to the implementation method of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, or a network device, etc.) to execute the above method according to the implementation method of the present application.

[0108] The software product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0109] Computer readable storage media may include data signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program codes contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0110] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0111] The computer-readable medium carries one or more programs. When the one or more programs are executed by a device, the computer-readable medium implements the aforementioned functions.

[0112] Those skilled in the art will appreciate that the above modules can be distributed in the device according to the description of the embodiment, or can be changed accordingly and only used in one or more devices different from the embodiment. The modules of the above embodiments can be combined into one module, or further divided into multiple sub-modules.

[0113] According to an embodiment of the present application, a computer program is provided, including a computer program or an instruction. When the computer program or the instruction is executed by a processor, the method described above can be executed.

[0114] According to an embodiment of the present application, a given superconducting quantum chip is mapped into an undirected graph, which is a basic element studied in graph theory. After finding the coloring number of the graph, the quantum bits are classified according to different colors, and decoupling operations are performed on quantum bits of different colors to decouple the interactions between the quantum bits, thereby eliminating the crosstalk caused by these interactions. The embodiments of the present application can be applied to quantum chips of any topological structure, and the complexity of the control is only related to the coloring number of the graph, and does not increase with the increase in the size of the chip.

[0115] The embodiments of the present application are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application. At the same time, changes or deformations made by those skilled in the art based on the ideas of the present application, the specific implementation methods and the scope of application of the present application, all belong to the scope of protection of the present application. In summary, the content of this specification should not be construed as a limitation on the present application.

Claims

1. A method for eliminating crosstalk between quantum bits in a superconducting quantum chip, characterized in that: include: In response to an instruction to eliminate crosstalk between quantum bits in a superconducting quantum chip, determining a topological structure corresponding to the superconducting quantum chip; Mapping the topological structure into an undirected graph; Classifying the vertices in the undirected graph so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different categories; Decomposing the undirected graph into a plurality of subgraphs according to the classification of vertices, so that each obtained subgraph includes only one classification; Control pulses are applied to the qubits corresponding to the edges connecting different subgraphs to eliminate crosstalk between qubits.

2. The elimination method according to claim 1, characterized in that: Determining a topological structure corresponding to the superquantum chip includes: The topological structure is determined according to the arrangement of quantum bits in the superconducting quantum chip and the interaction between quantum bits.

3. The elimination method according to claim 2, characterized in that: Mapping the topological structure into an undirected graph includes: Mapping the quantum bits in the superconducting quantum chip to vertices in the undirected graph; The interactions between quantum bits in the superconducting quantum chip are mapped to edges in the undirected graph.

4. The elimination method according to any one of claims 1 to 3, characterized in that: Classifying the vertices in the undirected graph so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different categories, including: The vertices in the undirected graph are colored, wherein the quantum bits at both ends of any edge in the undirected graph are colored with different colors.

5. The elimination method according to claim 4, characterized in that: Before decomposing the undirected graph into a plurality of subgraphs according to the classification of vertices so that each obtained subgraph includes only one classification, the method further includes: The coloring number is determined based on the colored map.

6. The elimination method according to claim 5, characterized in that: Decompose the undirected graph into multiple subgraphs according to the classification of vertices, so that each subgraph includes only one classification, including: Decomposing the undirected graph into two subgraphs according to the classification colors of the quantum bits to obtain a first subgraph and a second subgraph; Eliminating the connection between the first subgraph and the second subgraph by using a preset decoupling rule; If the coloring number of the first subgraph and / or the second subgraph is greater than 1, continue to decompose the first subgraph and / or the second subgraph, and use the decoupling rule to decouple the subgraphs after the decomposition of the first subgraph and / or the second subgraph until the coloring number of the subgraph of the first subgraph and / or the second subgraph is equal to 1.

7. The elimination method according to claim 6, characterized in that: Eliminating the connection between the first subgraph and the second subgraph by using a preset decoupling rule includes: Performing a first free evolution on quantum bits belonging to the first subgraph or the second subgraph among the quantum bits connecting the first subgraph and the second subgraph; Applying a Pauli-X operator to the quantum bit after the first free evolution; The quantum bit after the action is subjected to a second free evolution; A Pauli-X operator is applied to the quantum bit after the second free evolution.

8. A device for eliminating crosstalk between quantum bits in a superconducting quantum chip, characterized in that: include: A topology structure determination unit, configured to determine a topology structure corresponding to the superconducting quantum chip in response to an instruction to eliminate crosstalk between quantum bits in the superconducting quantum chip; An undirected graph generating unit, used for mapping the topological structure into an undirected graph to obtain a corresponding mapping graph; A quantum bit classification unit, used to classify the vertices in the undirected graph so that the quantum bits corresponding to the two ends of any edge in the undirected graph belong to different categories; A mapping graph decomposition unit, used for decomposing the undirected graph into a plurality of subgraphs according to the classification of vertices, until the obtained subgraphs include only one classification; The crosstalk elimination unit is used to apply control pulses to the quantum bits corresponding to the edges connecting different subgraphs to eliminate the crosstalk between the quantum bits.

9. An electronic device, comprising: processor; as well as A memory storing a computer program, which, when executed by the processor, enables the processor to perform the elimination method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having computer-readable instructions stored thereon, which, when executed by a processor, causes the processor to execute the elimination method according to any one of claims 1 to 7.

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