Method for transmitting quantum bits, storage medium, electronic device, computer program product

Abstract

The application discloses a quantum bit sending method, a storage medium, an electronic device and a computer program product. The quantum bit sending method applied to a central controller of a quantum network comprises the following steps: obtaining a target request forwarded by a first quantum router, the target request being a request sent by a first terminal for establishing a quantum connection between the first terminal and a second terminal, and the first quantum router forwarding the target request in a case where it is determined that the second terminal is not directly connected with the first quantum router; determining a first transmission mode according to a transmission requirement carried in the target request and setting a first request identifier for the target request; sending the first transmission mode and the first request identifier to the first quantum router and instructing the first quantum router to forward the first transmission mode and the first request identifier to the first terminal; and sending the first transmission mode and the first request identifier to a second quantum router and instructing the second quantum router to forward the first transmission mode and the first request identifier to the second terminal.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum communication, in particular to a method for transmitting a quantum bit, a storage medium, an electronic device and a computer program product. BACKGROUND

[0002] The emergence of the Internet has brought revolutionary influence on people's life. The current developing quantum computing, quantum communication and quantum sensing fields show amazing potential and advantages. It can be expected that the new network formed by connecting these quantum devices together, i.e. quantum network, can further amplify its advantages and bring changes to the world again. However, the current quantum network uses a fixed transmission mode to transmit quantum bits with different requests, resulting in the problem of poor transmission efficiency of quantum bits in the quantum network.

[0003] For the problem of poor transmission efficiency of quantum bits in the quantum network in the related art, no effective solution has been proposed so far.

[0004] Therefore, it is necessary to improve the related art to overcome the defects in the related art. SUMMARY

[0005] The embodiments of the present application provide a method for transmitting a quantum bit, a storage medium, an electronic device and a computer program product to at least solve the problem of poor transmission efficiency of quantum bits in the quantum network.

[0006] According to one embodiment of the present application, a method for transmitting quantum bits is provided, which is applied to a central controller of a quantum network, comprising: obtaining a target request forwarded by a first quantum router, wherein the target request is a request sent by a first terminal for establishing a quantum connection between the first terminal and a second terminal, the first quantum router forwarding the target request when determining that the second terminal is not directly connected to the first quantum router, and the first quantum router is a network node in the quantum network directly connected to the first terminal; determining a first transmission mode based on the transmission requirements carried in the target request, and setting a first request identifier for the target request, wherein the first transmission mode is a transmission mode corresponding to a transmission path, the transmission path being a path for the quantum network to realize the transmission of the quantum bit corresponding to the target request, and the first transmission mode and the first request are related. The first transmission mode and the first request identifier have a corresponding relationship; sending the first transmission mode and the first request identifier to the first quantum router, and instructing the first quantum router to forward the first transmission mode and the first request identifier to the first terminal, so that the first terminal sends the quantum bits corresponding to the target request according to the first transmission mode and the first request identifier; and sending the first transmission mode and the first request identifier to the second quantum router, and instructing the second quantum router to forward the first transmission mode and the first request identifier to the second terminal, so that the second terminal identifies the quantum bits corresponding to the target request according to the first request identifier, and processes the identified quantum bits according to the first transmission mode, wherein the second quantum router is a network node directly connected to the second terminal in the quantum network.

[0007] According to another aspect of an embodiment of the present application, a method for sending quantum bits is also provided, which is applied to a first quantum router, comprising: obtaining a target request sent by a first terminal, wherein the target request is used to request establishment of a quantum connection between the first terminal and a second terminal; if it is determined that the second terminal is not directly connected to the first quantum router, forwarding the target request to a central controller of a quantum network, wherein the first quantum router is a network node in the quantum network directly connected to the first terminal; obtaining a first transmission mode and a first request identifier of the target request determined by the central controller, and sending the first transmission mode and the first request identifier to the first terminal, so that the first terminal sends a quantum bit corresponding to the target request according to the first transmission mode and the first request identifier, wherein the first transmission mode is a transmission mode determined by the central controller according to the transmission requirements carried in the target request, and the first transmission mode and the first request identifier have a corresponding relationship.

[0008] According to another aspect of the present application, a computer-readable storage medium is provided, in which a computer program is stored. The computer program is configured to execute the steps of any one of the above method embodiments when running.

[0009] According to another aspect of the present application, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to perform the steps in any one of the above method embodiments.

[0010] According to another aspect of the present application, a computer program product is provided, including a computer program, which implements the steps in any one of the above method embodiments when executed by a processor.

[0011] In this application, the central controller of the quantum network can formulate different transmission modes according to different quantum requests, thereby ensuring the implementation of different quantum requests, improving the transmission efficiency of quantum bits in the quantum network, and solving the problem of poor transmission efficiency of quantum bits in quantum networks. In addition, the quantum network applicable to this application is also compatible with first-, second-, and third-generation quantum repeater technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0013] Figure 1 This is a hardware structure block diagram of a quantum terminal for a quantum bit transmission method according to an embodiment of the present application;

[0014] Figure 2 This is a flow chart of a method for sending quantum bits according to an embodiment of the present application;

[0015] Figure 3 This is a flow chart of another method for sending quantum bits according to an embodiment of the present application;

[0016] Figure 4 This is a schematic diagram of a quantum network design according to an embodiment of the present application;

[0017] Figure 5 This is a schematic diagram of a process for a local quantum request to establish a connection in an embodiment of the present application;

[0018] Figure 6 This is a schematic diagram of a process for establishing a remote quantum connection request according to an embodiment of the present application;

[0019] Figure 7 is a schematic diagram of quantum transmission according to an embodiment of the present application;

[0020] Figure 8 is a schematic diagram of another quantum transmission according to an embodiment of the present application;

[0021] Figure 9 is a schematic diagram of another quantum transmission according to an embodiment of the present application;

[0022] Figure 10 is a schematic diagram of another quantum transmission according to an embodiment of the present application;

[0023] Figure 11 This is a schematic diagram of another quantum transmission according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] The method embodiments provided in the embodiments of the present application can be executed in a quantum terminal (including but not limited to a quantum computer, a quantum sensor device). Taking running on a quantum terminal as an example, Figure 1 This is a hardware structure diagram of a quantum terminal for a quantum bit transmission method according to an embodiment of the present application. Figure 1 As shown, a quantum terminal may include one or more ( Figure 1Only one is shown in the figure) a classical processor 102 (the classical processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA), a quantum processor 103, a classical memory 104 for storing classical data, and a quantum memory 105 for storing quantum bits. The quantum terminal may also include a transmission device 106 for communication functions and an input / output device 108, wherein the input / output device 108 includes but is not limited to: a keyboard 1082 and a display 1084. It will be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above quantum terminal. Figure 1 More or fewer components than shown, or with Figure 1 Different configurations shown.

[0027] The quantum processor 105 can perform quantum gate operations or measurements on the quantum bits stored in the quantum memory 105 (the quantum processor 105 includes but is not limited to microwave and radio frequency pulse modules or laser systems).

[0028] The classical memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the quantum computer program corresponding to the method for transmitting qubits in the embodiments of the present application. The classical processor 102 and the quantum processor 103 execute various functional applications and process the qubits stored in the quantum memory by running the computer programs stored in the classical memory 104, thereby implementing the above-mentioned method. The classical memory 104 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the classical memory 104 may further include memory remotely located relative to the classical processor 102, and these remote memories may be connected to the quantum terminal via a network.

[0029] The quantum memory 105 can be used to store quantum bits. Currently, there are multiple technical routes such as superconductors, ion traps, neutral atoms, and semiconductors to realize quantum memory.

[0030] The transmission device 106 is used to receive or send classical information and quantum bits via a network. Specific examples of the above-mentioned network may include a wired network provided by the communication provider of the quantum terminal. In one embodiment, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the quantum network. In one embodiment, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the quantum network via optical fiber. Classical information and quantum bits can be transmitted separately through different optical fibers, or wavelength division multiplexing technology can be used to achieve multiplexing of classical channels and quantum channels.

[0031] It should be noted that the quantum network of this application is divided into two parts: the main network and the user-side network. The main network can be compatible with the first, second, and third generation quantum repeater technologies, and is responsible for transmitting quantum data or constructing entangled states between user-side quantum routers (such as Figure 4 As shown, Figure 4 The "cloud" part in the above is a main network, which includes multiple quantum routers. The user-side network adopts the third-generation quantum repeater technology, which is responsible for the transmission of quantum bits from the user end to the user-side router (such as Figure 4 As shown, Figure 4 The outside of the "cloud" in the example is the user-end network, which includes multiple user ends, such as Figure 4 A.1, A.2, E.2, E.1, etc.).

[0032] In this embodiment, a method for transmitting quantum bits is provided, which is applied to a central controller of a quantum network (optionally, the central controller is a quantum terminal). Figure 2 This is a flow chart of a method for sending quantum bits according to an embodiment of the present application. Figure 2 As shown, the process includes the following steps:

[0033] Step S202: Obtain a target request forwarded by a first quantum router, where the target request is a request sent by a first terminal for establishing a quantum connection between the first terminal and a second terminal. The first quantum router forwards the target request when determining that the second terminal is not directly connected to the first quantum router. The first quantum router is a network node in the quantum network that is directly connected to the first terminal.

[0034] Optionally, the first terminal and the second terminal are quantum terminals.

[0035] As an optional embodiment, the target request sent by the first terminal can be used not only to establish a quantum connection between the first terminal and the second terminal, but also to establish a quantum connection between the first terminal and multiple terminals.

[0036] It should be noted that both the first terminal and the second terminal are user terminals, and both need to support the third-generation quantum repeater technology and are responsible for transmitting quantum bits.

[0037] It's important to further clarify that the core of third-generation quantum repeater technology is quantum error correction. By performing quantum error correction on quantum frames in quantum repeaters and quantum routers, quantum information can be transmitted from the sender to the receiver. The quantum memory in quantum repeaters and quantum routers can be used to store quantum states for error correction and entanglement operations during transmission. Third-generation quantum repeater technology also involves the design and construction of quantum repeaters. Quantum repeaters and quantum routers must possess efficient quantum memory, stable quantum operations, and reliable quantum error correction mechanisms. Furthermore, quantum repeaters and quantum routers must establish reliable quantum channels with the sender and receiver to ensure the reliable transmission and recovery of quantum information.

[0038] It should be noted that if the first terminal is directly connected to the first quantum router, and the second terminal is not directly connected to the first quantum router, then the second terminal and the first terminal are not connected to the same network node, that is, the target request is a remote request. If the second terminal and the first terminal are connected to the same network node, then the target request is a local request.

[0039] That is to say, the network node connected to the first terminal in the quantum network will determine whether the target request is a local request or a remote request. If it is a remote request, the target request will be uploaded to the central controller for processing by the central processor.

[0040] Step S204: determining a first transmission mode according to the transmission requirement carried in the target request, and setting a first request identifier for the target request, wherein the first transmission mode is a transmission mode corresponding to a transmission path, and the transmission path is a path for the quantum network to realize the transmission of the quantum bits corresponding to the target request, and the first transmission mode and the first request identifier have a corresponding relationship;

[0041] It should be noted that the transmission path refers to the path formed by the quantum routers and quantum repeaters required to complete the target request in the main network, that is, the transmission path of the quantum bit in the main network. The path identifier of the transmission path is used to identify the transmission path. For example, path identifier a corresponds to the transmission path (quantum router 1-quantum router 2-quantum router 3-quantum router 4).

[0042] It should be noted that the transmission requirements include: the number of quantum bits to be transmitted, the form of the entangled state, end-to-end fidelity, throughput, and latency; the first transmission mode includes at least: parameter values ​​of multiple parameters, a path identifier of the transmission path, and a rule set or forwarding table; the multiple parameters include: quantum coding method, quantum error correction method, quantum frame size, and sending rate; the rule set includes a remote quantum entanglement generation scheme corresponding to each network node in the transmission path and the first request identifier and the path identifier; the forwarding table includes an output interface identifier corresponding to each network node in the transmission path and the first request identifier and the path identifier.

[0043] It should be noted that the form of the entangled state depends on the requirements of the quantum request. Common forms of entangled states in quantum networks include Bell states, GHZ states, W states, and ultra-dense states. Among them, the Bell state consists of two quantum bits and is also called the EPR state.

[0044] It's important to note that end-to-end fidelity refers to the fidelity of qubits when they are transmitted to the end device. Many quantum applications require high-fidelity qubits. Therefore, it's desirable for quantum networks to achieve high-fidelity transmission, minimizing information loss and errors during transmission.

[0045] It's important to clarify that throughput refers to the number of qubits a quantum network can process and transmit per unit time. For a quantum network, high throughput means it can simultaneously process and transmit more qubits, improving the network's efficiency and performance.

[0046] It's important to clarify that latency refers to the time it takes for quantum information to travel from the sender to the receiver. Latency in quantum networks includes transmission delay, processing delay, and queuing delay. It's hoped that quantum networks can achieve low latency to ensure fast and real-time information transmission.

[0047] As an optional example, the target request includes the name of the quantum application on the first terminal, the name of the second terminal and the name of the quantum application on it, and the requirements that the quantum network is expected to meet (i.e., the transmission requirements mentioned above). For example, the requirements that the quantum network is expected to meet include: the amount of quantum data transmitted or entangled states established, the minimum acceptable end-to-end fidelity, throughput, latency, etc.

[0048] Step S206: Send the first transmission mode and the first request identifier to the first quantum router, and instruct the first quantum router to forward the first transmission mode and the first request identifier to the first terminal, so that the first terminal sends the quantum bits corresponding to the target request according to the first transmission mode and the first request identifier;

[0049] Step S208: Send the first transmission mode and the first request identifier to a second quantum router, and instruct the second quantum router to forward the first transmission mode and the first request identifier to the second terminal, so that the second terminal identifies the quantum bits corresponding to the target request according to the first request identifier, and processes the identified quantum bits according to the first transmission mode, wherein the second quantum router is a network node directly connected to the second terminal in the quantum network.

[0050] It's important to note that the qubit is the fundamental unit of quantum computing, equivalent to the bit in classical computing. A bit is the smallest unit of computer storage and can only represent a state of 0 or 1, whereas a qubit can exist in a superposition of both 0 and 1. A qubit can be described using quantum mechanical state vectors, typically represented as |0> and |1>, where |0> represents the ground state, equivalent to the 0 state in a classical bit, and |1> represents the excited state, equivalent to the 1 state in a classical bit. Unlike a classical bit, a qubit can exist in a superposition of both states, represented as |ψ> = α|0> + β|1>, where α and β are complex numbers satisfying |α|^2 + |β|^2 = 1. This superposition property of qubits is precisely what enables efficient algorithms such as parallel computing and quantum parallel search in quantum computing.

[0051] In steps S202-S208, the central controller of the quantum network can formulate different transmission modes based on different quantum requests, thereby ensuring the fulfillment of different quantum requests, improving the transmission efficiency of qubits in the quantum network, and solving the problem of poor transmission efficiency of qubits in the quantum network. In addition, the quantum network applicable to this application is compatible with first-, second-, and third-generation quantum repeater technologies.

[0052] In an exemplary embodiment, determining a transmission path and a first transmission mode corresponding to the transmission path according to the transmission requirement carried in the target request may be implemented by the following steps S11-S12:

[0053] Step S11: Acquire quantum resource information of the quantum network, wherein the quantum resource information of the quantum network includes: quantum resource usage of the quantum network, link quality of the quantum network, and characteristics of each network node in the quantum network;

[0054] It should be noted that network nodes include quantum routers and quantum repeaters.

[0055] It should be noted that quantum resources refer to quantum bits in quantum routers and quantum repeaters.

[0056] It should be noted that the link quality of the quantum network is related to the signal attenuation degree, the transmission rate of the quantum bit, the noise of the quantum bit, and the fidelity of the quantum bit.

[0057] Step S12: determining a transmission path according to the transmission requirement carried in the target request and the quantum resource information of the quantum network, and determining a first transmission mode corresponding to the transmission path.

[0058] That is, the central controller will formulate a transmission scheme for the request according to the requirement of each request and the real-time network resource usage, and adopt a connection-oriented, fixed-path, and resource-reserved mode.

[0059] As an optional embodiment, the central controller will make a decision according to the content of the target request, the quantum resource usage of the subject network, the link quality, the characteristics of each network node, etc. The decision content includes: the steps of implementing the request, the corresponding path, the selection of the quantum repeater scheme of the first generation, the quantum encoding mode, the quantum error correction mode, the size of the quantum frame, the transmission rate, etc.

[0060] In an exemplary embodiment, setting a first request identifier for the target request can be achieved through the following steps S21-S22:

[0061] Step S21: sending a first inquiry request to the first terminal, the second terminal, the first quantum router, and the second quantum router, wherein the first inquiry request is used to determine whether the first terminal, the second terminal, the first quantum router, and the second quantum router have quantum resources supporting the first transmission mode; the second quantum router is a network node directly connected to the second terminal in the quantum network;

[0062] Step S22: setting the first request identifier for the target request in a case where it is determined that the first terminal, the second terminal, the first quantum router, and the second quantum router all have quantum resources supporting the first transmission mode.

[0063] As an optional example, in a case where it is determined that there is one of the first terminal, the second terminal, the first quantum router, and the second quantum router that does not support the quantum resources of the first transmission mode, sending prompt information to the first terminal and the second terminal, the first quantum router, and the second quantum router, wherein the prompt information is used to indicate that the target request cannot be performed.

[0064] That is, after determining the first transmission method, the central controller will inquire whether the user end and the connected quantum router involved in the target request have sufficient quantum resources to implement the solution. If the user end and the connected quantum router involved in the request check that the quantum memory resources can meet the request, they will reply a "yes" message to the central controller. If the request is not met, they will reply a "no" message to the central controller. If the central controller receives a "yes" message, it will assign a path ID and a unique request ID in the entire network (i.e., the first request identifier mentioned above) to the target request. If the central controller receives a "no" message, it will inform the user end and quantum router involved in the request that the target request cannot be carried out temporarily.

[0065] It should be noted that by querying the terminal and the quantum router connected to the terminal during the connection process whether there are sufficient quantum resources to complete the quantum request and the central controller fully allocating quantum resources in the main network, the problem of congestion in the quantum network when quantum resources are scarce is avoided.

[0066] In an exemplary embodiment, after setting a first request identifier for the target request, the method further comprises the following step S31: sending the first request identifier and a first transmission mode to the i-th network node in the transmission path, where the first transmission mode has a rule set or a forwarding table corresponding to the first request identifier and a path identifier of the transmission path, wherein the N network nodes in the transmission path include the first quantum router and the second quantum router; the second quantum router is a network node in the quantum network directly connected to the second terminal, N is a positive integer greater than or equal to 2, and i is a positive integer greater than or equal to 1 and less than or equal to N;

[0067] It should be noted that the rule set includes a remote quantum entanglement generation scheme corresponding to the i-th network node, the first request identifier, and the path identifier; the forwarding table includes an outbound interface identifier corresponding to the i-th network node, the first request identifier, and the path identifier;

[0068] It should be noted that the rule set corresponding to the first request identifier and the path identifier of the transmission path is used to instruct the i-th network node to perform quantum operations (quantum operations including but not limited to: entanglement generation operations, entanglement purification operations, and entanglement exchange operations) according to the remote quantum entanglement generation scheme in the rule set when receiving the rule set; the forwarding table corresponding to the first request identifier and the path identifier is used to instruct the i-th network node to prepare quantum error correction resources corresponding to the first request identifier and the path identifier of the transmission path when receiving the forwarding table.

[0069] That is to say, if the network nodes on the transmission path receive the rule sets corresponding to the first and second generation quantum repeater technologies, they will perform entanglement generation, entanglement purification, entanglement exchange, quantum error correction and other operations according to the instructions of the rule sets in the process of constructing remote entangled states, thereby realizing the establishment of remote entangled states between quantum routers, and then performing quantum teleportation or entanglement exchange operations after obtaining the quantum frame.

[0070] If the network nodes on the path receive the forwarding table corresponding to the third-generation quantum repeater technology, they need to prepare the resources required for quantum error correction in advance according to the request requirements. Then, when the quantum frame arrives, quantum error correction is performed and it is forwarded to the designated interface to the next hop. Quantum error correction is performed along the designated path and forwarded hop by hop to the target user end.

[0071] It should be noted that the network node that receives the rule set supports at least the first generation quantum repeater technology or the second generation quantum repeater technology, and the network node that receives the forwarding table supports at least the third generation quantum repeater technology.

[0072] It should be noted that first-generation quantum repeater technology refers to a technology that uses the principles of entanglement generation, entanglement purification, and quantum teleportation to establish high-fidelity remote entangled states, allowing quantum information to be transmitted from one location to another. This technology utilizes the characteristics of entangled states to achieve quantum information transmission.

[0073] It should be noted that the second-generation quantum repeater technology refers to the use of entanglement generation and quantum error correction to overcome losses in the transmission process, improve the quality of the entangled state, establish a high-fidelity remote entangled state, and can also use quantum teleportation to transmit quantum bits.

[0074] It should be further explained that different quantum operations are required for different quantum repeater technologies. Generally speaking, for first-generation quantum repeater technology, quantum entanglement, entanglement exchange, and entanglement purification are required, while for second-generation quantum repeater technology, quantum entanglement, entanglement exchange, and quantum error correction are required.

[0075] It's important to note that entanglement exchange isn't performed when the first and second quantum routers are directly adjacent. However, entanglement exchange is mandatory when the first and second quantum routers are not adjacent. Furthermore, entanglement purification and quantum error correction can be omitted for quantum routers with low requirements or high-quality links or nodes. In other words, quantum operations need to be selected based on the specific conditions of the quantum network.

[0076] In this embodiment, a method for transmitting quantum bits is provided, which is applied to a first quantum router. Figure 3This is a flow chart of another method for sending quantum bits according to an embodiment of the present application. Figure 3 As shown, the process includes the following steps:

[0077] Step S302: Obtain a target request sent by the first terminal, wherein the target request is used to request establishment of a quantum connection between the first terminal and the second terminal;

[0078] Step S304: if it is determined that the second terminal is not directly connected to the first quantum router, forward the target request to a central controller of the quantum network, wherein the first quantum router is a network node in the quantum network that is directly connected to the first terminal;

[0079] It should be noted that if the second terminal and the first terminal are not connected to the same quantum router, then in this case, the target request is a remote request. If the second terminal and the first terminal are connected to the same quantum router, then the target request is a local request.

[0080] In other words, the first quantum router will determine whether the target request is a local request or a remote request. If it is a remote request, the target request will be uploaded to the central controller for processing by the central processor.

[0081] Step S306: Obtain the first transmission mode determined by the central controller and the first request identifier of the target request, and send the first transmission mode and the first request identifier to the first terminal, so that the first terminal sends the quantum bits corresponding to the target request according to the first transmission mode and the first request identifier, wherein the first transmission mode is the transmission mode determined by the central controller according to the transmission requirements carried in the target request, and the first transmission mode has a corresponding relationship with the first request identifier.

[0082] In steps S302-S306, the central controller of the quantum network can formulate different transmission modes according to different quantum requests, thereby ensuring the realization of different quantum requests, improving the transmission efficiency of quantum bits in the quantum network, and solving the problem of poor transmission efficiency of quantum bits in the quantum network. In addition, the quantum network applicable to this application is compatible with first, second, and third generation quantum repeater technologies.

[0083] In an exemplary embodiment, after the above step S306, the following steps S41-S43 are further performed:

[0084] Step S41: Acquire a quantum frame sent by the first terminal, wherein a payload portion of the quantum frame includes the quantum bit;

[0085] It should be noted that the frame header of the quantum frame has a request identifier and a path identifier;

[0086] Optionally, it should be noted that the first terminal opens up the required quantum memory for the target request, and sends the quantum frame using the third-generation quantum repeater technology according to the first transmission mode, wherein the quantum frame consists of a frame header composed of classical bits and a payload composed of quantum bits.

[0087] Step S42: When it is determined that the frame header of the quantum frame includes the first request identifier and the path identifier, and the first quantum router includes a rule set corresponding to the first request identifier and the path identifier, performing a Bell state measurement on the quantum frame according to the entangled state between the first quantum router and a target quantum router to obtain a measurement result, wherein the rule set includes a remote quantum entanglement scheme corresponding to the first quantum router, the first request identifier, and the path identifier, the target quantum router and the first quantum router have a quantum entanglement relationship, and the first transmission mode includes the path identifier of the transmission path of the quantum bit sent by the first terminal in the quantum network;

[0088] Step S43: Send the measurement result to a target quantum router, so that the quantum frame is sent to the second terminal through the target quantum router.

[0089] It should be noted that the target quantum router may be the second quantum router or may not be the second quantum router.

[0090] It should be noted that the target quantum router performs corresponding quantum gate operations according to the entangled state between the target quantum router and the first quantum router and the measurement result to obtain a quantum frame.

[0091] In the case that the target quantum router is the second quantum router, the target quantum router directly forwards the obtained quantum frame to the second terminal.

[0092] In a case where the target quantum router is not the second quantum router, the target quantum router performs quantum error correction on the obtained quantum frame according to the quantum error correction resource corresponding to the first request identifier and the path identifier in the target quantum router, and forwards the corrected quantum frame to the next-hop network node according to the forwarding table in the target quantum router, so as to continue forwarding the quantum frame to the second terminal through the next-hop network node.

[0093] In an exemplary embodiment, after the above step S306, the following steps S51-S52 are further included:

[0094] Step S51: Acquire a quantum frame sent by the first terminal;

[0095] Step S52: When it is determined that the frame header of the quantum frame has the first request identifier and the path identifier, and the first quantum router has a forwarding table corresponding to the first request identifier and the path identifier, quantum error correction is performed on the quantum frame according to the quantum error correction resource corresponding to the first request identifier and the path identifier in the first quantum router, and the quantum frame is forwarded to a next-hop network node according to the forwarding table, so that the quantum frame is sent to the second terminal through the next-hop network node.

[0096] The forwarding table corresponding to the first request identifier and the path identifier in the first quantum router contains an outbound interface identifier corresponding to the first quantum router, and the outbound interface identifier has a corresponding relationship with the next-hop network node;

[0097] It should be noted that, in this embodiment, the frame header of the quantum frame does not need to carry information such as the destination address and port number.

[0098] It should be noted that since quantum devices have less quantum memory, in order to facilitate resource reservation on quantum routers and quantum repeaters, and to prepare quantum error correction resources in advance, the size of quantum frames under the same request is required to be the same.

[0099] It should be noted that the next-hop network node may be a second quantum router or may not be a second quantum router.

[0100] In the case that the next-hop network node is the second quantum router, the obtained quantum frame is directly forwarded to the second terminal.

[0101] If the next-hop network node is not the second quantum router and the next-hop network node has a forwarding table, continue to perform quantum error correction on the obtained quantum frame according to the quantum error correction resource corresponding to the first request identifier and the path identifier in the target quantum router, and continue to forward the error-corrected quantum frame to the next-hop network node according to the forwarding table in the target quantum router, so as to continue to forward the quantum frame to the second terminal through the next-hop network node;

[0102] When the next-hop network node is not the second quantum router and the next-hop network node has a rule set, Bell state measurement is performed on the quantum frame according to the entangled state between the next-hop network node and the specific quantum router, and the obtained measurement result is sent to the specific quantum router, so that the quantum frame is sent to the second terminal through the specific quantum router, wherein the specific quantum router has a quantum entangled relationship with the next-hop network node.

[0103] In an exemplary embodiment, after obtaining the target request sent by the first terminal, the following steps S61-S62 are further performed:

[0104] Step S61: When it is determined that the second terminal is directly connected to the first quantum router, a second transmission mode is determined based on the transmission requirements of the first terminal carried in the target request, the link quality of the first link, and the quantum resource information in the first quantum router, and a second request identifier is set for the target request; the first link includes: a quantum link between the first terminal and the first quantum router, and a quantum link between the second terminal and the first quantum router, wherein the second transmission mode has a corresponding relationship with the second request identifier;

[0105] It should be noted that when the second terminal is directly connected to the first quantum router, that is, there is only one first quantum router between the first terminal and the second terminal, in this case, the target request is a local request.

[0106] Step S62: Send the second transmission mode and the second request identifier to the first terminal, so that the first terminal sends the quantum bits corresponding to the target request according to the second transmission mode and the second request identifier.

[0107] In an exemplary embodiment, setting the second request identifier for the target request may be implemented by the following steps S71-S72:

[0108] Step S71: Sending a second query request to the first terminal and the second terminal, wherein the second query request is used to determine whether the first terminal and the second terminal have quantum resources supporting the second transmission mode;

[0109] Step S72: When it is determined that both the first terminal and the second terminal have quantum resources supporting the second transmission mode, the second request identifier is set for the target request.

[0110] In an exemplary embodiment, after setting the second request identifier for the target request, the following steps S81 are further performed:

[0111] Step S81: Sending the target request, the second request identifier, and the second transmission mode to the second terminal, so that the second terminal processes the quantum frame based on the second transmission mode when the request identifier in the frame header of the received quantum frame is the second request identifier.

[0112] In an exemplary embodiment, the above method further comprises the following steps S91:

[0113] Step S91: When the frame header of the quantum frame sent by the first terminal contains the second request identifier, quantum error correction is performed on the quantum frame according to the quantum error correction resources corresponding to the second transmission mode in the first quantum router, and the quantum frame after quantum error correction is sent to the second terminal, wherein the payload portion of the quantum frame includes the quantum bit.

[0114] That is, in this embodiment, if the first quantum router determines that the target request is a local request, it then calculates the required quantum encoding method, quantum error correction method, quantum frame size, transmission rate, and other information based on the request content and known link quality. It then checks whether its own quantum memory resources can meet the requirements. If so, it sets a second request identifier for the target request and records the corresponding request information and outbound interface information. It then notifies the client involved in the request of the request, the calculation scheme, and the label.

[0115] Obviously, the embodiments described above are only part of the embodiments of the present invention, rather than all the embodiments. In order to better understand the above method, the above process is described below in conjunction with the embodiments, but it is not intended to limit the technical solutions of the embodiments of the present invention. Specifically:

[0116] It should be noted that existing quantum networks have the following characteristics:

[0117] 1. Due to the high difficulty in developing quantum devices, the scale of quantum networks may be very small in the foreseeable future, such as only a few hundred quantum devices, and the amount of quantum memory in each device will also be relatively small.

[0118] 2. Different quantum applications have different requirements for the network, such as end-to-end fidelity, throughput, latency, etc. If the network does not meet the requirements, the quantum application will not work.

[0119] 3. Quantum bits have different characteristics from classical bits. They cannot be copied, so the most common copy and retransmission technology in classical networks cannot be used. They are also very fragile and prone to decoherence, and the transfer of quantum states will also reduce their quality.

[0120] 4. Currently, there are multiple technologies for transmitting quantum bits, such as the first and second generation quantum repeater technologies that construct remote entangled states for quantum teleportation and the third generation quantum repeater technology that uses quantum error correction for hop-by-hop forwarding. The construction of remote entangled states requires the coordinated operation of quantum routers and quantum repeaters along the path.

[0121] Currently, there is no comprehensive quantum network design that is compatible with first-, second-, and third-generation quantum repeater technologies and capable of supporting diverse quantum applications, given the limited resources available. This application, based on the concept of a service customized network (SCN), proposes a holistic quantum network design and a specific process for implementing quantum requests.

[0122] As an optional example, Figure 4 This is a schematic diagram of a quantum network design according to an embodiment of the present application. Generally speaking, it includes the following designs:

[0123] 1. The entire quantum network is divided into two parts: the main network and the user-side network. The main network can be compatible with the first, second, and third generation quantum repeater technologies, responsible for transmitting quantum data or building entangled states between user-side quantum routers. The user-side network adopts the third generation quantum repeater technology, responsible for the user side (such as Figure 4 A.1) to the user-side router (a router directly connected to the user side, such as Figure 4 Quantum data transmission of the network node numbered 1 in the network.

[0124] 2. Due to the small scale of quantum networks, the limited quantum memory of quantum devices and the high requirements of quantum applications on the network, autonomous domains are eliminated in quantum networks, and the main network adopts centralized control with unified regulation of the entire network. The central controller issues rule sets and forwarding tables to quantum routers and quantum repeaters.

[0125] 3. The central controller develops a customized solution based on the requirements of each request and the real-time network resource usage, and adopts a connection-oriented, fixed-path, and reserved resource model.

[0126] 4. Cancel the MAC address, IP address, and port number representation.

[0127] 5. When transmitting quantum data, the packet header carries the request ID and path ID, and does not need to carry information such as source and destination addresses, port numbers, etc.

[0128] 6. Since quantum devices have less quantum memory, in order to facilitate resource reservation on quantum routers and quantum repeaters, and to prepare quantum error correction resources in advance, the size of quantum frames under the same request is required to be the same.

[0129] 7. Since it is assumed that the quantum computer has less quantum memory and in order to avoid the quality degradation caused by multiple transfers of quantum states, it is assumed that the quantum computer does not distinguish between local quantum memory and quantum network card.

[0130] Furthermore, completing a quantum request involves the following two aspects:

[0131] (1) Establishing a connection:

[0132] 1. A client that wishes to establish a connection sends a request to a connected quantum router. The request includes the name of the quantum application on the client, the name of the target client and the name of the quantum application on it, as well as the desired quantum network requirements, such as the amount of quantum data to be transmitted or the amount of entangled states to be established, and the minimum acceptable end-to-end fidelity, throughput, and latency.

[0133] 2. The quantum router determines whether the request is a local request. If it is a local request, the quantum router makes the decision. If it is not a local request, the request is uploaded to the central controller for decision making. Specifically:

[0134] (1) If it is a local request, the quantum router calculates the quantum encoding method, quantum error correction method, quantum frame size, transmission rate, etc. required for the request based on the content of the request and the known link quality, and checks whether its own quantum memory resources can meet the requirements. If so, a local request ID tag is set for the request, and the information corresponding to the request and the output interface information are recorded. Then the request, calculation scheme, tag, etc. are notified to the user end involved in the request, such as Figure 5 FIG. 1 is a flow chart of a local quantum request to establish a connection in an embodiment of the present application.

[0135] (2) If it is a remote request, the central controller makes a decision based on the content of the request, the quantum resource usage of the main network, the link quality, the characteristics of each quantum router, etc. The decision content includes: the steps to implement the request, the corresponding path, the selection of the generation of quantum repeater scheme, quantum encoding method, quantum error correction method, quantum frame size, transmission rate, etc. Figure 6 FIG. 1 is a flow chart of a remote quantum request to establish a connection according to an embodiment of the present application.

[0136] 3. Ask whether the user end involved in the request and the connected quantum router have sufficient quantum resources to implement the solution.

[0137] 4. If the client involved in the request and the connected quantum router check that the quantum memory resources can meet the request, they will reply a "yes" message to the central controller. If the request is not met, they will reply a "no" message to the central controller. Specifically:

[0138] (1) If the central controller receives a “yes” message, it assigns a path ID and a network-wide unique request ID to the request, sends the ID and the corresponding rule set or forwarding table to the quantum routers and quantum repeaters on the selected path, and informs the user end involved in the request that the connection is established.

[0139] (2) If the central controller receives a "no" message, it informs the user end involved in the request that the request cannot be carried out temporarily.

[0140] (2) Transmitting qubits:

[0141] 1. The client allocates the required quantum memory for the request and uses third-generation quantum repeater technology to send a quantum frame as required, with the request ID and path ID marked in the packet header. The quantum frame consists of a header composed of classical bits and a payload composed of quantum bits.

[0142] 2. If the quantum routers and quantum repeaters along the path receive the rule sets corresponding to first- and second-generation quantum repeater technology, they will perform operations such as entanglement generation, entanglement purification, entanglement exchange, and quantum error correction according to the instructions in the rule sets during the transmission of quantum bits, thereby establishing a remote entangled state between the quantum routers on the user side. The user side then transmits the quantum data or entangled photons to the quantum router on the user side for quantum teleportation or entanglement exchange operations.

[0143] 3. If the quantum routers and quantum repeaters on the path receive the forwarding table corresponding to the third-generation quantum repeater technology, they need to prepare the resources required for quantum error correction in advance according to the request requirements. When the quantum frame arrives, quantum error correction is performed and it is forwarded to the designated interface to the next hop. Quantum error correction is performed along the designated path and forwarded hop by hop to the target user end.

[0144] For a better understanding, the technical solution of this application is described in detail below with reference to specific embodiments, wherein: Figure 4 Quantum routers 7 and 8 can only use first-generation quantum repeater technology, while other quantum routers can use first, second, and third-generation quantum repeater technology:

[0145] Example 1: Figure 7 As shown, user terminal A.1 sends a quantum frame to user terminal A.2;

[0146] (1) User A.1 sends a request to quantum router 1. The request content includes: the name of the quantum application on A.1, the name of the target user A.2 and its quantum application name, and the requirements for the quantum frames to be transmitted (including but not limited to: quantity, minimum fidelity, minimum throughput, etc.; for example, if 10 quantum bits of data need to be transmitted, the minimum fidelity is 0.9 and the minimum throughput is 2 qubits / s).

[0147] (2) After receiving the request, quantum router 1 checks to determine that the target user A.2 is a local user. Then, based on the request content, link quality and other information (such as the error rate of quantum bits on the two optical fibers from A.1 and A.2 to quantum router 1, the distance of the optical fibers, the rate of generating quantum bits, the rate of quantum error correction, the quantum memory size of the quantum router, etc.), it calculates the required encoding method, error correction method, the size of each quantum frame, the sending rate, etc. (for example, the calculation result is to use the teleportation-based error correction (TEC) quantum error correction protocol, using (3, 3)-quantumparity The system checks whether its memory resources can satisfy the request (requiring 18 x 3 physical qubits, 18 of which are used to store the incoming quantum data and 18 x 2 to prepare the entangled state required for quantum error correction). If so, it sets a local request tag, local_id, for the request (e.g., local_id = 1), and records the request information and the corresponding output interface information (interfaces 2 and 3) under this tag. It then notifies users A.1 and A.2 of the request, the calculated information, and the local request tag.

[0148] (3) After receiving the message, user A.1 checks whether its own memory resources (at least 18 physical quantum bits are required to prepare quantum data) can meet the calculation results of quantum router 1, and then replies with a "yes" message to router 1. After receiving the message, user A.2 checks whether its own memory resources (at least 18*3 physical quantum bits, of which 18 physical quantum bits are used to store the upcoming quantum data and 18*2 physical quantum bits are used to prepare the entangled state required for quantum error correction) can complete the request. If so, it records the request information and returns a "yes" message to quantum router 1.

[0149] (4) After receiving the confirmation information from users A.1 and A.2, quantum router 1 sends a message requesting formal establishment to users A.1 and A.2. If the error correction method is TEC, the entangled state required for error correction needs to be prepared in advance for the request.

[0150] (5) After receiving the information that the request has been formally established, users A.1 and A.2 allocate the required quantum memory for the request. User A.1 sends the quantum frame as required (each frame contains 2 logical quantum bits, i.e. 18 physical quantum bits) and marks the local_id of the request in the packet header. After receiving the quantum frame marked with the local_id, quantum router 1 performs error correction and forwarding operations according to the reserved information (such as storing the quantum bit part of the quantum frame in the reserved quantum memory, and then using the pre-prepared entangled state to perform quantum error correction. After the error correction is completed, the generated new quantum bits are encapsulated into a new quantum frame and forwarded from interface 2 of quantum router 1 to user A.2). After receiving it, user A.2 performs error correction and measurement according to the reserved information and transfers the quantum data to the memory area where the corresponding quantum application is located.

[0151] Example 2: Figure 8 As shown, user end A.1 sends a quantum frame to user end B.1. The transmission path in the quantum network is network nodes 1-6-7-2 (using only the first generation quantum repeater technology);

[0152] (1) User A.1 sends a request to quantum router 1. The request content includes: the name of the quantum application on A.1, the name of the target user B.1 and its quantum application name, and the requirements for the quantum frames to be transmitted (such as quantity, minimum fidelity, minimum throughput, etc.).

[0153] (2) After receiving the request, quantum router 1 checks that the target user B.1 is not a local user, and then sends the request to the central controller.

[0154] (3) The central controller makes a decision based on the request requirements and the resource usage and link quality in the main network, and asks A.1 and B.1 and the quantum routers connecting them whether they have the resources to implement the solution. (For example, the decision is to use the first-generation quantum repeater technology to establish the remote entangled state between quantum routers 1-6-7-2, as well as the specific resource allocation and operation process. If the user uses the TEC quantum error correction protocol and adopts the (3,3)-QPC encoding method, each quantum frame sent contains 1 logical quantum bit, that is, there are 9 physical quantum bits. Quantum router 1 needs to prepare 9*3+20 physical quantum bits of quantum memory resources for storage, quantum error correction, entanglement generation, entanglement purification, and quantum teleportation operations; quantum router 2 needs to prepare 9*2+20 physical quantum bits of quantum memory resources for entanglement generation, entanglement purification, and quantum error correction operations; quantum routers 6 and 7 need to prepare 40 physical quantum bits of resources for entanglement generation, entanglement purification, and entanglement exchange operations).

[0155] (4) When the central controller receives their reply “yes” message, it assigns a path id and a request id unique to the entire network to the request, and sends the path id, request id and the corresponding rule set to all quantum routers and repeaters that need to participate in the request (a rule set is an object consisting of one or more rules, each rule contains a condition and an operation. For example, for quantum routers 6 and 7, the received rule set includes: when the quantum bit is initialized and the startup message is received, the entanglement generation operation is performed; when the entangled state is generated, the entanglement purification operation is performed; when the purification is completed, the entanglement exchange operation is performed. For quantum For sub-router 1, the received rule set includes: upon qubit initialization and receipt of the startup message, perform entanglement generation; upon the generation of an entangled state, perform entanglement purification; and upon receiving a successful entanglement exchange message from quantum routers 6 and 7, perform quantum teleportation. For quantum router 2, the received rule set includes: upon qubit initialization and receipt of the startup message, perform entanglement generation; upon the generation of an entangled state, perform entanglement purification; and upon receiving the quantum teleportation measurement result from quantum router 1, perform operations on the qubits and perform quantum error correction. After receiving the message (e.g., path ID = 3, request ID = 2), quantum routers 1 and 2 forward it to the user.

[0156] (5) After receiving the message that the request is officially established, users A.1 and B.1 allocate the required quantum memory for the request. User A.1 sends the quantum frame as required and marks the request ID and path ID in the packet header.

[0157] (6) Quantum routers 1, 6, 7, and 2 perform collaborative operations according to the contents of the rule sets they have received. First, entangled states are generated between 1-6, 6-7, and 7-2 (the 20 quantum bits assigned to interface 1 of quantum router 1 are entangled with the 20 quantum bits assigned to interface 1 of quantum router 6, the 20 quantum bits assigned to interface 2 of quantum router 6 are entangled with the 20 quantum bits assigned to interface 1 of quantum router 7, and the 20 quantum bits assigned to interface 2 of quantum router 7 are entangled with the 20 quantum bits assigned to interface 1 of quantum router 2. These assigned quantum bits are all marked with path id = 3 and request id = 2). Then, entanglement purification is performed to improve fidelity. Then, quantum routers 6 and 7 perform entanglement exchange operations (the marked paths of interface 1 and interface 2 in quantum router 6 are 3). , request id = 2 for entanglement exchange operation, the path id = 3 marked between interface 1 and interface 2 in quantum router 7, request id = 2 for entanglement exchange operation), when the entanglement exchange is successful, the message is notified to quantum routers 1 and 2, at this time the remote entangled state between quantum routers 1 and 2 has been established, when quantum router 1 receives the quantum frame of A.1, it stores it in the reserved quantum memory, first performs quantum error correction operation, then performs quantum teleportation operation with the remote entangled state just established in interface 1 of router 1, and informs quantum router 2 of the measurement result of the operation. After receiving the measurement result, router 2 operates on the path id = 3 marked in its interface 1, request id = 2, and performs quantum error correction operation, assembles it into a new quantum frame, and forwards it to user B.1 through interface 3.

[0158] Example 3: Figure 9 As shown, user terminal A.1 sends a quantum frame to user terminal C.1. The transmission path in the quantum network is network nodes 1-6-10-9-3 (using only third-generation quantum repeater technology);

[0159] (1) User A.1 sends a request to quantum router 1. The request content includes: the name of the quantum application on A.1, the name of the target user C.1 and its quantum application name, and the requirements for the quantum frames to be transmitted, such as the number, minimum fidelity, minimum throughput, etc.

[0160] (2) After receiving the request, quantum router 1 checks that the target user C.1 is not a local user, and then sends the request to the central controller.

[0161] (3) The central controller makes a decision based on the request requirements and the resource usage and link quality of the main network, asking A.1 and C.1 and the quantum routers connecting them whether they have the resources to implement the solution. (For example, the decision is to use third-generation quantum repeater technology, with the path of quantum routers 1-6-10-9-3, as well as the specific resource allocation and operation process. If the user uses the TEC quantum error correction protocol, using the (3,3)-QPC encoding method, each quantum frame sent contains one logical quantum bit, that is, there are 9 physical quantum bits. Quantum routers 1, 6, 10, 9, and 3 each need to prepare a quantum memory resource of 9*3 physical quantum bits for storage and quantum error correction operations).

[0162] (4) When the central controller receives their reply "yes", it assigns a path ID and a request ID unique to the entire network to the request, and sends the path ID and request ID (e.g., path ID = 4, request ID = 3) and the corresponding forwarding table (for path ID = 4, request ID = 3, the forwarding table corresponding to quantum router 1 is interface 1; the forwarding table corresponding to router 6 is interfaces 1 and 3; the forwarding table corresponding to router 10 is interfaces 1 and 3; the forwarding table corresponding to router 9 is interfaces 1 and 3; the forwarding table corresponding to router 3 is interface 1) to all quantum routers and repeaters that need to participate in the request. After receiving the message, quantum routers 1 and 3 forward it to the user.

[0163] (5) After receiving the formal establishment message, users A.1 and C.1 allocate the required quantum memory for the request. User A.1 sends the quantum frame as required, marking the request ID and path ID in the packet header. Quantum routers 1, 6, 10, 9, and 3 reserve 9*3 physical quantum bits of quantum memory resources and prepare 9*2 of them into the entangled state required for quantum error correction.

[0164] (6) After receiving the quantum frame marked with path id = 4 and request id = 3, quantum router 1 uses the TEC quantum error correction protocol to perform error correction according to the instructions previously received from the central controller. After the error correction is completed, a new quantum frame is generated and forwarded to interface 1 according to the forwarding table. Then the quantum frame reaches quantum router 6. Similarly, after receiving the quantum frame marked with path id = 4 and request id = 3, router 6 uses the TEC quantum error correction protocol to perform error correction according to the instructions previously received from the central controller. After the error correction is completed, a new quantum frame is generated and forwarded to interface 3 according to the forwarding table. And so on. The quantum frames reach quantum routers 10, 9, and 3 in turn, undergo quantum error correction and forward, and finally reach user C.1.

[0165] Example 4: Figure 10As shown, user end A.1 sends a quantum frame to user end C.1. The transmission path in the quantum network is network nodes 1-6-7-8-9-3 (where 6-7-8-9 use the first-generation quantum repeater technology, and 1-6 and 9-3 use the third-generation quantum repeater technology).

[0166] (1) User A.1 sends a request to quantum router 1. The request content includes: the name of the quantum application on A.1, the name of the target user C.1 and its quantum application name, and the requirements for the quantum frames to be transmitted, such as the number, minimum fidelity, minimum throughput, etc.

[0167] (2) After receiving the request, quantum router 1 checks that the target user C.1 is not a local user, and then sends the request to the central controller.

[0168] (3) The central controller makes a decision based on the request requirements and the resource usage and link quality in the main network (assuming that the request in Example 3 is still running, resulting in insufficient quantum memory in quantum router 10, so the central controller selects another path for the request in Example 4). It asks A.1 and C.1 and the quantum routers connecting them whether they have the resources to implement the solution. (For example, if the decision is that the path is 1-6-7-8-9-3, since quantum routers 7 and 8 only support first-generation quantum repeater technology, the 6-7-8-9 segment of the path adopts first-generation quantum repeater technology, and the 1-6 and 9-3 segments adopt third-generation quantum repeater technology. If the user uses the TEC quantum error correction protocol, using the (3,3)-QPC encoding method, each quantum frame sent contains one logical quantum bit, that is, there are 9 physical quantum bits. The decision also includes the resources that need to be reserved for each quantum router).

[0169] (4) When the central controller receives their reply “yes” message, it assigns a path id and a request id unique to the entire network to the request, and assigns the path id and request id (e.g., path id = 5, request id = 4) and the corresponding rule set and forwarding table (under path id = 5, request id = 4, the forwarding table corresponding to quantum router 1 is interface 1; the forwarding table corresponding to router 3 is interface 1. For quantum routers 7 and 8, the received rule set includes: when the quantum bit is initialized and the startup message is received, the entanglement generation operation is performed; when the entangled state is generated, the entanglement purification operation is performed; when the purification is completed, the entanglement exchange operation is performed. For quantum router 6, the received rule set includes: when the quantum bit is initialized and the startup message is received, the entanglement generation operation is performed; when the entanglement state is generated, the entanglement purification operation is performed; when the purification is completed, the entanglement exchange operation is performed. After receiving the startup message, entanglement generation occurs. Once an entangled state is generated, entanglement purification is performed. Upon receiving a quantum frame with path ID = 5 and request ID = 4, it is stored and quantum error correction is performed using the TEC protocol. Upon receiving a successful entanglement exchange message from quantum routers 7 and 8, quantum teleportation is performed. Quantum router 9 receives the following rule set: upon qubit initialization and receipt of the startup message, entanglement generation occurs. Once an entangled state is generated, entanglement purification is performed. Upon receiving the quantum teleportation measurement result from quantum router 6, qubit operations are performed and quantum error correction is performed. This rule set is then forwarded from interface 3 to all quantum routers and repeaters that need to participate in the request. Quantum routers 1 and 3 receive the message and forward it to the user.

[0170] (5) After receiving the message that the request is officially established, users A.1 and C.1 allocate the required quantum memory for the request. User A.1 sends the quantum frame as required and marks the request ID and path ID in the packet header. Quantum router 1 needs to prepare quantum memory resources of 9*3 physical qubits, of which 9 qubits are used to store the upcoming quantum frame, and 9*2 qubits are prepared in advance as entangled states required for quantum error correction. Quantum router 6 needs to prepare quantum memory resources of 9*3+20 physical qubits for storage, quantum error correction, entanglement generation, entanglement purification, and quantum teleportation operations. The use of 9*3 qubits is the same as that of router 1, and 20 qubits are used to construct entangled states. Quantum routers 7 and 8 need to prepare quantum memory resources of 40 physical qubits for entanglement generation, entanglement purification, and entanglement swapping operations. Quantum router 9 needs to prepare quantum memory resources of 20+9*2 physical qubits for quantum error correction, entanglement generation, and entanglement purification operations. Quantum router 3 needs to prepare quantum memory resources of 9*3 physical qubits for storage and quantum error correction operations.

[0171] (6) Quantum routers 6, 7, 8, and 9 perform collaborative operations according to the contents of the rule sets they receive. First, entangled states are generated between 6 and 7, 7 and 8, and 8 and 9 (the 20 qubits assigned to interface 2 of quantum router 6 are entangled with the 20 qubits assigned to interface 1 of quantum router 7, the 20 qubits assigned to interface 3 of quantum router 7 are entangled with the 20 qubits assigned to interface 1 of quantum router 8, the 20 qubits assigned to interface 2 of quantum router 8 are entangled with the 20 qubits assigned to interface 2 of quantum router 9). The 20 assigned qubits are entangled, and these assigned qubits are marked with path id = 5, request id = 4). Then, entanglement purification is performed to improve fidelity. Then, quantum routers 7 and 8 perform entanglement exchange operations (entanglement exchange operations are performed between the qubits with path id = 5 and request id = 4 marked between interface 1 and interface 3 in quantum router 7, and entanglement exchange operations are performed between the qubits with path id = 5 and request id = 4 marked between interface 1 and interface 2 in quantum router 8). When the entanglement exchange is successful, the message is notified to the quantum router. Routers 6 and 9 have now established a remote entangled state between them. After receiving the quantum frame marked with path id = 5 and request id = 4, quantum router 1 uses the TEC quantum error correction protocol to perform error correction according to the instructions previously received from the central controller. After the error correction is completed, a new quantum frame is generated and forwarded to interface 1 according to the forwarding table. Then, the quantum frame reaches quantum router 6. Similarly, after receiving the quantum frame marked with path id = 5 and request id = 4, router 6 uses the TEC quantum error correction protocol to perform error correction according to the instructions previously received from the central controller. After the error correction is completed, a new quantum frame is generated. Then, the generated remote entangled state between routers 6 and 9 is used to perform quantum teleportation operation and inform quantum router 9 of the measurement result of the operation. After receiving the measurement result, router 9 operates on the quantum bits marked with path id = 5 and request id = 4 in its interface 2, performs quantum error correction operation, assembles a new quantum frame, and forwards it to router 3 through interface 3. After receiving the quantum frame, router 3 stores it, performs quantum error correction operation, and then forwards it to user C.1.

[0172] Example 5: Figure 11 As shown, user terminals A.1, B.2, and D.1 share three entangled states. Starting from quantum router 10, three entangled states are generated and then sent to A.1, B.2, and D.1 respectively. The transmission paths are: 10-6-1, 10-7-2, and 10-9-4. Among them, 10-6-1 and 10-9-4 use the third-generation quantum repeater technology, and 10-7-2 uses the first-generation quantum repeater technology.

[0173] (1) User A.1 sends a request to Router 1. The request content includes: the application name on A.1, the names of target users B.2 and D.1 and the above application name, and the requirements for the quantum frames to be transmitted, such as the number, minimum fidelity, minimum throughput, etc.

[0174] (2) After receiving the request, quantum router 1 checks that the target users B.2 and D.1 are not local users, and then sends the request to the central controller.

[0175] (3) The central controller makes a decision based on the request requirements and information such as resource usage and link quality in the main network, asking A.1, B.2, and D.1, as well as the routers connecting them, whether they have the resources to implement the solution. (For example, the solution is to first generate a three-part entangled state from quantum router 10. Each quantum frame contains a logical quantum bit and uses the (3,3)-QPC encoding method, that is, it is composed of 9 physical quantum bits. It is then sent to the three users via three paths 10-6-1, 10-7-2, and 10-9-4 respectively. Since router 7 only supports first-generation quantum repeater technology, 10-7-2 uses first-generation quantum repeater technology, and 10-6-1 and 10-9-4 use third-generation quantum repeater technology).

[0176] (4) When the central controller receives their reply “yes” message, it assigns a path id and a request id unique to the entire network to the request (e.g., request id = 5, id = 6 for the path 10-6-1, id = 7 for the path 10-7-2, id = 8 for the path 10-9-4), and sends the path id and request id and the corresponding rule set or forwarding table (e.g., the rule set received by quantum router 10 is: generate a three-part entangled state in (3, 3)-QPC encoding mode, forward a part of it with request id = 5 and path id = 6 from interface 1, and forward a part of it with request id = 5 and path id = 8 from interface 3, assign 20 quantum bits to interface 2 to generate entanglement with quantum router 7 and perform entanglement purification, and upon receiving the message of successful entanglement exchange from router 7, transmit a part of the generated three-part entangled state with request id = 5 and path id = 7 through quantum teleportation, and send the measurement result to router 2; quantum router 7 receives the message of successful entanglement exchange from router 7, The received rule set includes the following: When qubit initialization is complete and the startup message is received, perform entanglement generation; when an entangled state is generated, perform entanglement purification; and when purification is complete, perform entanglement exchange. Quantum router 2 also receives the following rule set: When qubit initialization is complete and the startup message is received, perform entanglement generation; when an entangled state is generated, perform entanglement purification; and upon receiving the quantum teleportation measurement results from router 10, perform operations on the qubits and perform quantum error correction. Quantum router 6 receives a forwarding table with request ID = 5 and path ID = 6 corresponding to interfaces 1 and 3; quantum router 1 receives a forwarding table with request ID = 5 and path ID = 6 corresponding to interface 1; quantum router 9 receives a forwarding table with request ID = 5 and path ID = 8 corresponding to interfaces 1 and 4; and quantum router 4 receives a forwarding table with request ID = 5 and path ID = 8 corresponding to interface 1. These rules are then distributed to all quantum routers and repeaters that need to participate in the request. The user-side router receives the message and forwards it to the user.

[0177] (5) After receiving the message of the request of formal establishment, the users A.1, B.2 and D.1 open the required quantum memory for the request, and the quantum routers 1, 6, 9 and 4 need to prepare 9*3 physical quantum bit quantum memory resources, in which 9 quantum bits are used to store the upcoming quantum frame, and 9*2 quantum bits are prepared in advance to be used for entanglement states required for quantum error correction; the quantum router 7 needs to prepare 40 physical quantum bit quantum memory resources to generate entanglement, entanglement purification, and entanglement exchange operations; the quantum router 2 needs to prepare 20+9*2 physical quantum bit quantum memory resources to generate quantum error correction, entanglement, and entanglement purification operations; the quantum router 10 needs to prepare 9*3+20 physical quantum bit quantum memory resources to generate three-part entanglement states, entanglement, entanglement purification, and quantum teleportation operations, in which 9*3 quantum bits are used to generate three-part entanglement states encoded by (3, 3)-QPC, and 20 quantum bits are used to construct entanglement states required for the next quantum teleportation;

[0178] (6) Quantum router 10 generates a (3, 3)-QPC-encoded three-part entangled state as required and encapsulates it into three quantum frames. One quantum frame has a header with request id = 5 and path id = 6 and is forwarded by interface 1. Another quantum frame has a header with request id = 5 and path id = 8 and is forwarded by interface 3. Another quantum frame has a header with request id = 5 and path id = 7 and waits for the establishment of the remote entangled state between routers 10 and 2 generated at interface 2. After the establishment, the quantum teleportation operation is performed. Quantum routers 10, 7, and 2 operate in coordination, according to the rulesets they each receive. First, an entangled state is generated between 10-7 and 7-2 (the 20 qubits assigned by interface 2 of quantum router 10 are entangled with the 20 qubits assigned by interface 4 of quantum router 7, and the 20 qubits assigned by interface 2 of quantum router 7 are entangled with the 20 qubits assigned by interface 1 of quantum router 2. These assigned qubits are all marked with path id = 7 and request id = 5). Then, entanglement purification is performed to improve fidelity, and then quantum router 7 performs an entanglement exchange operation (quantum path entanglement). In device 7, an entanglement exchange operation is performed between the qubits labeled with path ID = 7 and request ID = 5 on interface 4 and interface 2. When the entanglement exchange is successful, a message is transmitted to quantum routers 10 and 2, establishing a remote entangled state between them. Quantum router 10 can then perform quantum teleportation on the generated quantum frame labeled with path ID = 7 and request ID = 5, and send the measurement result to quantum router 2. After receiving the measurement result, quantum router 2 operates on the qubits and performs quantum error correction. After the error correction is complete, a new quantum frame is generated and forwarded to user B.2. After receiving the quantum frame, quantum routers 6, 1, 9, and 4 perform error correction according to the reserved information (previously received from the central controller) and forward it to users A.1 and D.1. Upon receiving the quantum frame, the users perform quantum error correction according to the reserved information and transfer the data to the memory area where the corresponding quantum application resides.

[0179] The following technical effects can be achieved through this application:

[0180] 1. Make the main quantum network compatible with first, second and third generation quantum repeater technologies;

[0181] 2. Develop different solutions based on the different needs of quantum requests;

[0182] 3. Taking into account the reality of insufficient quantum resources, when establishing a connection, the client involved in the request is asked whether it has sufficient quantum resources to meet the requirements, avoiding request failures due to insufficient resources on the client side. The central controller also monitors the quantum resource status of the main network to avoid quantum network congestion.

[0183] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus the necessary general hardware platform, of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product. The quantum computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a quantum terminal device with quantum operation capabilities to execute the methods described in each embodiment of the present application.

[0184] This embodiment also provides a central controller and a first quantum router, which are used to implement the above-mentioned embodiments and preferred implementations. Details already described will not be repeated here. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0185] The computer-readable storage medium stores a computer program, wherein the computer program is configured to execute the steps of any one of the above method embodiments when running.

[0186] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk, or an optical disk.

[0187] An embodiment of the present application further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0188] In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0189] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail here.

[0190] An embodiment of the present application further provides a computer program product, including a computer program, which implements the steps of any of the above method embodiments when executed by a processor.

[0191] An embodiment of the present application further provides another computer program product, comprising a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of any of the above method embodiments are implemented.

[0192] Obviously, those skilled in the art should understand that the modules or steps of the present application described above can be implemented using a general-purpose computing device, they can be concentrated on a single computing device, or distributed across a network composed of multiple computing devices, they can be implemented using program code executable by the computing device, and thus, they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be performed in a different order than herein, or they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0193] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for transmitting quantum bits, characterized in that: Applicable to central controllers, including: Obtaining a target request forwarded by a first quantum router, wherein the target request is a request sent by a first terminal for establishing a quantum connection between the first terminal and a second terminal, and the first quantum router forwards the target request when determining that the second terminal is not directly connected to the first quantum router, and the first quantum router is a network node in the quantum network directly connected to the first terminal; Determining a first transmission mode according to the transmission requirement carried in the target request, and setting a first request identifier for the target request, wherein the first transmission mode is a transmission mode corresponding to a transmission path, the transmission path being a path for the quantum network to implement transmission of the quantum bits corresponding to the target request, and the first transmission mode and the first request identifier have a corresponding relationship; sending the first transmission mode and the first request identifier to the first quantum router, and instructing the first quantum router to forward the first transmission mode and the first request identifier to the first terminal, so that the first terminal sends the quantum bits corresponding to the target request according to the first transmission mode and the first request identifier; and Sending the first transmission mode and the first request identifier to a second quantum router, and instructing the second quantum router to forward the first transmission mode and the first request identifier to the second terminal, so that the second terminal identifies the quantum bits corresponding to the target request according to the first request identifier, and processes the identified quantum bits according to the first transmission mode, wherein the second quantum router is a network node directly connected to the second terminal in the quantum network.

2. The method according to claim 1, characterized in that Determining a first transmission mode according to the transmission requirement carried in the target request includes: Acquiring quantum resource information of a quantum network, wherein the quantum resource information of the quantum network includes: quantum resource usage of the quantum network, link quality of the quantum network, and characteristics of each network node in the quantum network; The transmission path is determined according to the transmission requirements carried in the target request and the quantum resource information of the quantum network, and the first transmission mode corresponding to the transmission path is determined.

3. The method according to claim 1, characterized in that Setting a first request identifier for the target request includes: Sending a first query request to the first terminal, the second terminal, the first quantum router, and the second quantum router, wherein the first query request is used to determine whether the first terminal, the second terminal, the first quantum router, and the second quantum router have quantum resources that support the first transmission mode; the second quantum router is a network node in the quantum network directly connected to the second terminal; When it is determined that the first terminal, the second terminal, the first quantum router, and the second quantum router all have quantum resources supporting the first transmission mode, the first request identifier is set for the target request.

4. The method according to claim 1, wherein After setting the first request identifier for the target request, the method further includes: Sending the first request identifier and a first transmission mode to the i-th network node in the transmission path, where the first transmission mode has a rule set or a forwarding table corresponding to the first request identifier and a path identifier of the transmission path, wherein the N network nodes in the transmission path include the first quantum router and a second quantum router; the second quantum router is a network node in the quantum network directly connected to the second terminal, N is a positive integer greater than or equal to 2, and i is a positive integer greater than or equal to 1 and less than or equal to N; The rule set includes a remote quantum entanglement generation scheme corresponding to the i-th network node, the first request identifier, and the path identifier; the forwarding table includes an outbound interface identifier corresponding to the i-th network node, the first request identifier, and the path identifier; The rule set corresponding to the first request identifier and the path identifier of the transmission path is used to instruct the i-th network node to perform a quantum operation according to the remote quantum entanglement generation scheme in the rule set when receiving the rule set; the forwarding table corresponding to the first request identifier and the path identifier is used to instruct the i-th network node to prepare the quantum error correction resources corresponding to the first request identifier and the path identifier of the transmission path when receiving the forwarding table; The network node that receives the rule set supports at least the first generation quantum repeater technology or the second generation quantum repeater technology, and the network node that receives the forwarding table supports at least the third generation quantum repeater technology.

5. A method for transmitting quantum bits, characterized in that: Applied to the first quantum router, including: Obtaining a target request sent by a first terminal, wherein the target request is used to request establishment of a quantum connection between the first terminal and a second terminal; forwarding the target request to a central controller of a quantum network when it is determined that the second terminal is not directly connected to the first quantum router, wherein the first quantum router is a network node in the quantum network that is directly connected to the first terminal; Obtain a first transmission mode determined by the central controller and a first request identifier of the target request, and send the first transmission mode and the first request identifier to the first terminal, so that the first terminal sends quantum bits corresponding to the target request according to the first transmission mode and the first request identifier, wherein the first transmission mode is a transmission mode determined by the central controller according to the transmission requirements carried in the target request, and the first transmission mode has a corresponding relationship with the first request identifier.

6. The method according to claim 5, characterized in that After sending the first transmission mode and the first request identifier to the first terminal, the method further includes: Obtaining a quantum frame sent by the first terminal, wherein a payload portion of the quantum frame includes the quantum bit; When it is determined that the frame header of the quantum frame has the first request identifier and the path identifier, and the first quantum router has a rule set corresponding to the first request identifier and the path identifier, performing a Bell state measurement on the quantum frame according to the entangled state between the first quantum router and a target quantum router to obtain a measurement result, wherein the rule set includes a remote quantum entanglement scheme corresponding to the first quantum router, the first request identifier, and the path identifier, the target quantum router has a quantum entanglement relationship with the first quantum router, and the first transmission mode includes the path identifier of the transmission path of the quantum bit sent by the first terminal in the quantum network; The measurement result is sent to a target quantum router, so that the quantum frame is sent to the second terminal through the target quantum router.

7. The method according to claim 6, characterized in that After obtaining the quantum frame sent by the first terminal, the method further includes: When it is determined that the frame header of the quantum frame has the first request identifier and the path identifier, and the first quantum router has a forwarding table corresponding to the first request identifier and the path identifier, performing quantum error correction on the quantum frame according to the quantum error correction resource corresponding to the first request identifier and the path identifier in the first quantum router, and forwarding the quantum frame to a next-hop network node according to the forwarding table, so that the quantum frame is sent to the second terminal through the next-hop network node. The forwarding table corresponding to the first request identifier and the path identifier in the first quantum router contains an output interface identifier corresponding to the first quantum router, and the output interface identifier has a corresponding relationship with the next-hop network node.

8. The method according to claim 5, characterized in that After obtaining the target request sent by the first terminal, the method further includes: When it is determined that the second terminal is directly connected to the first quantum router, determining a second transmission mode according to the transmission requirement of the first terminal carried in the target request, the link quality of the first link, and the quantum resource information in the first quantum router, and setting a second request identifier for the target request, wherein the first link includes: a quantum link between the first terminal and the first quantum router, and a quantum link between the second terminal and the first quantum router; and the second transmission mode and the second request identifier have a corresponding relationship; The second transmission mode and the second request identifier are sent to the first terminal, so that the first terminal sends the quantum bits corresponding to the target request according to the second transmission mode and the second request identifier.

9. The method according to claim 8, characterized in that Setting a second request identifier for the target request includes: Sending a second query request to the first terminal and the second terminal, wherein the second query request is used to determine whether the first terminal and the second terminal have quantum resources supporting the second transmission mode; When it is determined that both the first terminal and the second terminal have quantum resources supporting the second transmission mode, the second request identifier is set for the target request.

10. The method according to claim 8, characterized in that After setting the second request identifier for the target request, the method further includes: The target request, the second request identifier, and the second transmission mode are sent to a second terminal, so that the second terminal processes the quantum frame based on the second transmission mode when the request identifier in the frame header of the received quantum frame is the second request identifier.

11. The method according to claim 8, characterized in that The method further comprises: When the obtained quantum frame sent by the first terminal contains the second request identifier in a frame header, quantum error correction is performed on the quantum frame according to quantum error correction resources corresponding to the second transmission mode in the first quantum router, and the quantum frame after quantum error correction is sent to the second terminal, wherein a payload portion in the quantum frame includes the quantum bit.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method of any one of claims 1 to 4 or 5 to 11 when executed.

13. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method according to any one of claims 1 to 4 or 5 to 11 through the computer program.

14. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 4 or 5 to 11 is implemented.

Images