Gateway device

Abstract

A gateway device according to the present disclosure is for connecting a quantum internet and a quantum intranet, receives information representing communication quality between a quantum node in the quantum intranet and other quantum nodes, the communication quality being calculated at said quantum node, constructs a routing table for the quantum intranet, receives a request from a node in the quantum internet, refers to the routing table for the quantum intranet, and, on the basis of the referred routing table, transmits the request to a quantum node in the quantum intranet.

Description

Gateway Device

[0001] The present disclosure relates to a gateway device.

[0002] In recent years, quantum networks such as the quantum internet have been attracting attention as next-generation communication technologies (see, for example, Non-Patent Document 1). For example, a quantum network is a network in which nodes (also called "quantum nodes") that realize quantum information processing technologies such as quantum computers are connected via optical fibers, free space, or the like to communicate (also called "quantum communication").

[0003] “Quantum Internet White Paper: The Quantum Internet – The Ultimate Cyberspace Permitted by the Physical Laws of the Universe,” Quantum Internet Task Force, Industry-Government-Academia Collaborative Research and Development Consortium, https: / / qitf.org / files / 20210210_qitf_whitepaper.pdf (accessed September 15, 2023)

[0004] However, it cannot be said that sufficient consideration has been given to the operation of quantum networks, such as the appropriate routing when communicating information over the quantum network, and the appropriate construction and maintenance of the quantum network, and there is room for improvement in the operation of quantum networks. Therefore, it is desirable to enable the appropriate operation of quantum networks.

[0005] Therefore, the present disclosure proposes a gateway device that can enable the appropriate operation of a quantum network.

[0006] In order to solve the above problems, a gateway device of one form according to the present disclosure is a gateway device for connecting a quantum internet and a quantum intranet, which receives information representing the communication quality between the quantum node and other quantum nodes calculated by the quantum node in the quantum intranet, constructs a routing table for the quantum intranet, receives a request from a node in the quantum internet, refers to the routing table for the quantum intranet, and transmits the request to a quantum node in the quantum intranet based on the referred routing table.

[0007] FIG. 1 is a diagram illustrating a configuration example of an information processing system according to an embodiment of the present disclosure; FIG. 2 is a diagram illustrating a configuration example of a gateway device according to an embodiment of the present disclosure; FIG. 3 is a sequence diagram illustrating an example of processing related to a first task; FIG. 4 is a sequence diagram illustrating an example of processing related to a second task; FIG. 5 is a sequence diagram illustrating an example of processing related to the second task; FIG. 6 is a sequence diagram illustrating an example of processing related to the second task; FIG. 7 is a sequence diagram illustrating an example of processing related to the third task; FIG. 8 is a sequence diagram illustrating an example of processing related to a fourth task; FIG. 9 is a sequence diagram illustrating an example of processing related to the fifth task; FIG. 10 is a sequence diagram illustrating an example of processing related to the fifth task; FIG. 11 is a sequence diagram illustrating an example of processing related to the sixth task; FIG. 12 is a sequence diagram illustrating an example of processing related to the sixth task; FIG. 13 is a sequence diagram illustrating an example of processing related to the seventh task; FIG. 14 is a sequence diagram illustrating an example of processing related to the eighth task; FIG. 15 is a sequence diagram illustrating an example of processing related to the eighth task.

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the gateway device according to the present application is not limited to these embodiments. In addition, in the following embodiments, the same components are designated by the same reference numerals, and redundant description will be omitted.

[0009] The present disclosure will be described in the following order:1. Overview 1-1. Quantum and Classical 1-2. Quantum Network 2. Embodiment 2-1. Configuration Example of Information Processing System 2-2. Configuration Example of Gateway Device 2-3. Configuration Example of Other Components (Quantum Nodes) 3. Tasks and Processing Examples 3-1. First Task (Routing within a Quantum Data Center) 3-1-1. Overview of First Task 3-1-2. Processing Example for First Task 3-1-2-1. Distributed Routing 3-1-2-2. Centralized Routing 3-2. Second Task (Establishing Trust with Clients) 3-2-1. Overview of Second Task 3-2-2. Processing Example for Second Task 3-2-2-1. Establishing Classical Trust 3-2-2-2. Establishing Quantum State Trust 3-3. Third Task (Participating in the Quantum Internet) 3-3-1. Overview of Third Task 3-3-2. Processing Example for Third Task 3-4. 3-4. Fourth Task (Routing Outside the Quantum Data Center) 3-4-1. Overview of the Fourth Task 3-4-2. Example of Processing for the Fourth Task 3-5. Fifth Task (Leaving the Quantum Internet) 3-5-1. Overview of the Fifth Task 3-5-2. Example of Processing for the Fifth Task 3-5-2-1. Normal Leaving 3-5-2-2. Classical Equipment Failure 3-5-2-3. Quantum Equipment Failure 3-6. Sixth Task (Monitoring Internal Information) 3-6-1. Overview of the Sixth Task 3-6-2. Example of Processing for the Sixth Task 3-6-2-1. Device Health Check 3-6-2-2. Link Health Check 3-7. Seventh Task (Communication Quality Guarantee, Resource Reservation) 3-7-1. Overview of the Seventh Task 3-7-2. Example of Processing for the Seventh Task 3-8. Eighth Task (Handling Internal Failures) 3-8-1. Overview of the Eighth Task 3-8-2. Processing example related to the 8th task 3-8-2-1. Abnormal stop of QPD 3-8-2-2. Abnormal stop of QRR 3-8-2-3. Link cost abnormality 3-9. Ninth task (logging) 3-9-1. Overview of the 9th task 3-9-2. Processing example related to the 9th task 4. Other 5. Effects of the present disclosure 6. Hardware configuration example.

[0010] [1. Overview] Before describing the present disclosure, an overview of the present disclosure will be described.

[0011] [1-1. Quantum and Classical] In the present disclosure, components that do not apply the principles of quantum mechanics and rely on classical physics (ordinary components) may be explicitly described with the term "classical" in order to clearly indicate that they are different from quantum-related components.

[0012] For example, to clearly indicate that they are different from quantum computers, ordinary computers that rely on classical physics may be referred to as classical computers. For example, a classical computer is a component that performs information processing such as calculations (operations) using so-called bits (also called "classical bits"), while a quantum computer is a component that performs information processing such as calculations (operations) using qubits (quantum states), which are bits with a different concept from classical bits. Hereinafter, the functions possessed by a classical computer may be referred to as classical functions, and the functions possessed by a quantum computer may be referred to as quantum functions.

[0013] Furthermore, for example, an ordinary network based on classical physics may be referred to as a classical network to clearly indicate that it is different from a quantum network. Furthermore, for example, an ordinary Internet based on classical physics may be referred to as a classical Internet to clearly indicate that it is different from a quantum Internet. Furthermore, for example, an ordinary intranet based on classical physics may be referred to as a classical intranet to clearly indicate that it is different from a quantum intranet.

[0014] [1-2. Quantum Network] Quantum networks such as the quantum internet are technologies that transfer quantum states (quantum information), which are information handled by quantum nodes such as quantum computers, via a network. The quantum state referred to here is realized as a physical state of a system represented by, for example, photons, and is essentially different from classical bits (classical information) exchanged over classical networks such as the classical internet. The biggest problem with the difference between quantum states (quantum information) and classical information when implementing a network is that quantum states cannot be replicated due to the quantum cloning theorem, etc.

[0015] For example, when classical information is transmitted (also called "classical communication") between distant components (devices, etc.) via optical fibers or the like through a classical network, a repeater is installed along the way to electrically amplify the signal that has been attenuated by propagation through the optical fibers, etc. Such amplification cannot be achieved in principle in a quantum network.

[0016] Therefore, a different method is required to communicate quantum information (also called "quantum communication") between distant components and relay the information during transmission and reception. Elemental technologies such as quantum entanglement swapping (also simply called "entanglement swapping") have been proposed as such a method, and active research is being conducted to achieve high-quality communication. To maximize the use of communication networks, protocols are developed and implemented to maximize their performance. However, given the above situation, many existing protocols for classical networks cannot be applied to quantum networks.

[0017] In particular, quantum states are extremely vulnerable to external disturbances, so it is necessary to efficiently generate resources to realize routing, which selects the optimal route on the network, and quantum entanglement, which corresponds to maintaining the communication state in quantum information. Routing here means determining the route from one node to another on the network.

[0018] For example, quantum entanglement is a correlation between quantum states that cannot be classically reproduced, and is a phenomenon that can be used to transfer quantum states through quantum teleportation, etc. Quantum teleportation (also simply called "teleportation") is a protocol for transferring any quantum state to a remote location, including quantum entanglement generation, measurement, feedback operation, etc. Entanglement swapping is a protocol for sharing quantum entanglement between quantum devices such as quantum nodes that are multiple hops away by performing measurements on entangled states and teleporting the entanglement.

[0019] By the way, if we consider a future where the quantum internet is established (laid down) as an analogy to the classical internet, we can imagine a situation where users communicate with quantum data centers via the quantum internet and use computing resources over the network. In this case, from the perspective of the quantum data center, there is a boundary between the internal synchronously managed intranet and the external asynchronously distributed Internet. When considering the protocols at this interface, it is natural that new protocols for quantum networks will need to be developed.

[0020] Therefore, this disclosure proposes tasks and protocol-related processing to be performed by a gateway device (QGW: Quantum Gateway), which is an example of a device placed at the boundary between a quantum data center (quantum intranet) and a quantum internet, assuming a quantum network.

[0021] [2. Embodiment] Hereinafter, an example of an embodiment based on the above-mentioned premise will be described.

[0022] [2-1. Configuration example of information processing system] First, an information processing system 1 shown in Fig. 1 will be described. Fig. 1 is a diagram showing a configuration example of an information processing system according to an embodiment of the present disclosure. The information processing system 1 is a system that enables processing using quantum information.

[0023] For example, the information processing system 1 functions as a quantum network system for communicating quantum information (quantum states) via a quantum network. The information processing system 1 is also a quantum-classical hybrid system that functions as both a quantum network system and a classical network system for communicating classical information via a classical network.

[0024] As shown in FIG. 1, the information processing system 1 includes components within a quantum data center 2 (QDC #1) (hereinafter also referred to as "components within QDC #1") and components outside QDC #1 (hereinafter also referred to as "components outside QDC #1").

[0025] The quantum data center 2 includes, as components within the QDC#1, a plurality of quantum repeater / routers (QRRs) 10a, a plurality of quantum processing devices (QPDs) 20, a gateway device 100, and the like within the quantum data center 2. For example, the quantum data center 2 constructs a network in which a plurality of quantum devices (such as the QPDs 20) are connected by quantum links, and provides clients with services (applications) that utilize the quantum network, such as distributed quantum computing.

[0026] The quantum network resources referred to here correspond to quantum entanglement, primarily Bell states, consumed on the network. The client referred to here is an entity requesting a service (such as CLT 30, described below). For example, a client such as CLT 30 may be a quantum or classical computer of an individual or organization requesting a service provided by the quantum network.

[0027] Although seven QRRs 10a are illustrated in FIG. 1, the number of QRRs 10a included in the quantum data center 2 is not limited to seven and may be any number. Furthermore, although two QPDs 20, QPD 20-1 (QPD#1) and QPD 20-2 (QPD#2), are illustrated in FIG. 1, the number of QPDs 20 included in the quantum data center 2 is not limited to two and may be any number. Furthermore, when there is no need to distinguish between QPDs 20-1, 20-2, etc. as described above, they may be referred to as QPDs 20. A plurality of gateway devices 100 (sometimes referred to as "QGWs 100") may be included in the quantum data center 2.

[0028] 1, components within QDC #1, such as QRR 10a, QPD 20, and gateway device 100, are connected via a classical intranet CN1 to enable classical communication. For example, the classical intranet CN1 is a network (intranet) for communicating classical information within the quantum data center 2. Note that the communication mode via the classical intranet CN1 can be any communication mode as long as classical communication is possible within the quantum data center 2, and may be a wired communication mode using optical fiber or the like, or a wireless communication mode such as free space.

[0029] In Figure 1, due to the relationship between the illustration, only the upper two QRRs 10a are shown with connection lines to the classical intranet CN1, but each QRR 10a with classical functions is connected via the classical intranet CN1 so that classical communication is possible with other components (devices, etc.) with classical functions within the quantum data center 2.

[0030] 1, the components within QDC#1, such as QRR 10a, QPD 20, and gateway device 100, are connected to enable quantum communication via a quantum intranet QN1. For example, the quantum intranet QN1 is a network (intranet) for communicating quantum information within the quantum data center 2. For example, the quantum intranet QN1 connects the components within QDC#1 to quantum communication via a wired communication mode using optical fiber or the like.

[0031] In addition, the communication mode of the quantum intranet QN1 is not limited to wired communication using optical fiber, etc., and any communication mode can be adopted as long as quantum communication is possible within the quantum data center 2, and may be, for example, a wireless communication mode such as free space.

[0032] For example, the QRR 10a is a component having at least one function of a router or a repeater in the quantum data center 2. For example, the QRR 10a has at least one function of a router (quantum router) or a repeater (quantum repeater) in quantum communication. The QRR 10a may also have at least one function of a router or a repeater in classical communication. For example, the QRR 10a communicates (transfers) quantum states (quantum information) with other components using quantum teleportation techniques based on quantum entanglement swapping and classical communication.

[0033] For example, the QPD 20 is a component that functions as a quantum computer used to perform distributed quantum computing. The QPD 20 includes a processor (quantum processor) that performs quantum computing, such as a QPU (Quantum Processing Unit). In FIG. 1, the QPD 20 is a quantum computing device located within the quantum data center 2, performs various quantum computations, and transmits (transfers) the computation results to other components, such as the adjacent QRR 10a.

[0034] The gateway device 100 is a component that functions as a gateway of the quantum data center 2. The gateway device 100 is used to connect a quantum intranet to the quantum internet. For example, the gateway device 100 connects a quantum intranet QN1 in the quantum data center 2 to a quantum internet QN2, which will be described later.

[0035] The gateway device 100 may have any function depending on the configuration of the quantum data center 2. For example, if the gateway device 100 has the function (authority) of serving as a network controller of the quantum data center 2, it may have the authority to issue commands to all components (devices) within the quantum intranet QN1.

[0036] Furthermore, for example, the gateway device 100 may reside on the gateway router of the quantum data center 2 as an end node process of the quantum data center 2, and may not have the function (authority) to directly control other components (QRR 10a, etc.) within the quantum intranet QN1. The gateway device 100 may function as the gateway router, or the QRR 10a located at the interface between the quantum data center 2 and the outside may function as the gateway router. In this case, the gateway device 100 may connect the quantum intranet QN1 to the quantum internet QN2 by controlling the QRR 10a functioning as the gateway router.

[0037] Furthermore, the information processing system 1 includes, as components outside the QDC#1, an EQRR (External Quantum Repeater / Router) 10b, which is a plurality of QRRs outside the quantum data center 2, and a plurality of CLTs (Clients) 30. Note that the components outside the QDC#1 are not limited to the above and may include various components such as IQRs (Intermediate Quantum Repeaters) 10c (see FIG. 9), which will be described later, but this point will be discussed later. Hereinafter, when the QRRs 10a, EQRRs 10b, IQRs 10c (see FIG. 9), etc. are not to be distinguished from one another, they may be referred to as relay nodes 10. Furthermore, when the relay nodes 10 and QPDs 20, etc. are not to be distinguished from one another, they may be referred to as quantum nodes.

[0038] 1 illustrates seven EQRRs 10b, but the number of EQRRs 10b included in the quantum data center 2 is not limited to seven and may be any number. Also, in FIG. 1, two CLTs 30, CLT30-1 (CLT#1) and CLT30-2 (CLT#2), are illustrated, but the number of CLTs 30 included in the quantum data center 2 is not limited to two and may be any number. Note that when there is no need to distinguish between CLTs 30-1, 30-2, etc. as described above, they may be referred to as CLTs 30.

[0039] 1, components outside QDC#1, such as EQRR10b and CLT30, and the gateway device 100 are connected via the classical Internet CN2 so that classical communication is possible. For example, the classical Internet CN2 is a network (Internet) for communicating classical information outside the quantum data center 2. Note that the communication mode via the classical Internet CN2 can be any communication mode as long as classical communication is possible outside the quantum data center 2, and may be a wired communication mode using optical fiber or the like, or a wireless communication mode such as free space.

[0040] In FIG. 1, for the EQRR 10b, due to the relationship shown in the figure, only the upper two EQRR 10b are shown with connection lines to the classical Internet CN2, but each EQRR 10b with classical functions is connected via the classical Internet CN2 so as to enable classical communication with other components with classical functions outside the quantum data center 2. When describing networks for classical communication such as the classical intranet CN1 and the classical Internet CN2 without distinguishing between them, they may be referred to as the classical network CN.

[0041] 1, the gateway device 100 and components outside QDC#1, such as EQRR10b and CLT30, are connected to enable quantum communication via the quantum internet QN2. For example, the quantum internet QN2 is a network (internet) for communicating quantum information outside the quantum data center 2. For example, the quantum internet QN2 connects the components outside QDC#1 to quantum communication via a wired communication mode using optical fiber or the like.

[0042] Note that the communication mode of the quantum internet QN2 is not limited to wired communication using optical fiber or the like, and any communication mode can be adopted as long as quantum communication is possible outside the quantum data center 2, and may be wireless communication such as free space. Furthermore, when describing networks for quantum communication such as the quantum intranet QN1 and the quantum internet QN2 without distinguishing between them, they may be referred to as the quantum network QN.

[0043] Also, for example, in FIG. 1, nodes directly connected by an undirected line (thick line) indicating the quantum network QN may be described as adjacent nodes. For example, adjacent nodes are nodes that communicate directly in the quantum network QN. In FIG. 1, of the seven EQRRs 10b, the rightmost EQRR 10b is connected to CLT30-2 via the quantum internet QN2, and the rightmost EQRR 10b is the adjacent node of CLT30-2, and CLT30-2 is the adjacent node of the rightmost EQRR 10b. Also, of the seven QRRs 10a, the leftmost QRR 10a is connected to QPD20-1 via the quantum intranet QN1, and the leftmost QRR 10a is the adjacent node of QPD20-1, and QPD20-1 is the adjacent node of the leftmost QRR 10a.

[0044] For example, the EQRR 10b is a component having at least one function of a router or a repeater outside the quantum data center 2. For example, the EQRR 10b has at least one function of a router (quantum router) or a repeater (quantum repeater) in quantum communication. For example, the EQRR 10b communicates (transfers) quantum states (quantum information) with other components by quantum teleportation techniques using quantum entanglement swapping and classical communication.

[0045] For example, the CLT 30 is a component that requests a service from the quantum data center 2. For example, the CLT 30 may be a device having quantum functionality (a quantum device) that is used by a user outside the quantum data center 2.

[0046] 1, the relay node 10, the QPD 20, the CLT 30, the gateway device 100, etc. have both classical functions and quantum functions. Note that for each of the components that require both classical functions and quantum functions, any configuration can be adopted as long as it has both classical functions and quantum functions; this point will be described later using the configuration of the gateway device 100 as an example.

[0047] Note that the above is merely an example, and any configuration can be adopted for the information processing system 1 as long as it can realize the desired processing. For example, the information processing system 1 may include a CA (Certificate Authority) 40 that functions as an entity (such as a certification authority) that issues certificates in processing related to tasks described below. Furthermore, for example, the information processing system 1 may include a Network Manager (NMG) 50 that functions as a network manager in processing related to tasks described below if the NMG 50 is a computer. Note that if the gateway device 100 functions as the NMG 50, the information processing system 1 does not need to include the NMG 50.

[0048] [2-2. Example Configuration of Gateway Device] Next, a configuration of a gateway device 100, which is an example of a gateway device that executes information processing according to an embodiment, will be described. FIG. 2 is a diagram illustrating an example configuration of a gateway device according to an embodiment of the present disclosure. Note that the configuration shown below is merely an example, and the gateway device 100 may have any configuration other than the configuration shown below as long as it has the desired functions. For example, the gateway device 100 may not have the quantum memory unit 160. Furthermore, for example, the gateway device 100 may have an input unit (e.g., a keyboard, a mouse, etc.) that accepts various operations from an administrator of the gateway device 100, and a display unit (e.g., a liquid crystal display, etc.) that displays various information.

[0049] 2, the gateway device 100 has a classical function unit 110 and a quantum function unit 150. For example, the classical function unit 110 and the quantum function unit 150 are connected to each other via a communication path using any configuration such as an I / O adapter so that information can be exchanged between them.

[0050] For example, the classical function unit 110 is a component corresponding to a part (classical computer unit) realized by a classical computer. In FIG. 2, the classical function unit 110 has a memory unit 120, a control unit 130, and a communication unit 140.

[0051] The storage unit 120 stores various types of information using classical memory. The storage unit 120 is realized, for example, by semiconductor memory elements such as RAM (Random Access Memory) or flash memory, or storage devices such as hard disks or optical disks. The storage unit 120 stores various types of information used in processing. The storage unit 120 stores classical information. For example, the storage unit 120 stores various types of classical information used in processing related to each of the first to ninth tasks described below. For example, the storage unit 120 stores various types of information such as routing tables and thresholds used in processing related to tasks. The routing table here refers to a table (information) that stores, for example, the address of a destination node (device, etc.) and information related to the route.

[0052] The control unit 130 may be implemented by a processor (classical processor) or circuit that performs classical computation. The control unit 130 is implemented, for example, by a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), or the like executing a program stored inside the gateway device 100 (for example, an information processing program such as the information processing program according to the present disclosure) using a random access memory (RAM) or the like as a working area. The control unit 130 is also implemented, for example, by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0053] The control unit 130 executes processing using information received from other components. The control unit 130 executes processing using information stored in the storage unit 120. The control unit 130 acquires various pieces of information from other components or the storage unit 120.

[0054] The control unit 130 executes various processes related to classical functions. The control unit 130 executes classical computation. For example, the control unit 130 executes processes related to classical functions among the processes related to each of the first to ninth tasks described below. For example, the control unit 130 executes processes related to each task using various information such as a routing table and thresholds stored in the storage unit 120.

[0055] The control unit 130 may control the quantum function unit 150. In this case, the control unit 130 may transmit a control signal or the like to the quantum function unit 150 and obtain processing results such as calculation results (measurement results) by the quantum function unit 150 from the quantum function unit 150.

[0056] The communication unit 140 is realized by, for example, a network interface card (NIC). The communication unit 140 is connected to the classical network CN by wire or wirelessly, and communicates information with other components. For example, the communication unit 140 communicates classical information with other components.

[0057] The communication unit 140 is connected to the classical intranet CN1 by wire or wirelessly, and communicates information with the components in the quantum data center 2. The communication unit 140 communicates information with the relay nodes 10 (QRR 10a, etc.), QPD 20, etc. in the quantum data center 2 via the classical intranet CN1.

[0058] The communication unit 140 is also connected to the classical Internet CN2 via a wired or wireless connection, and communicates information with components outside the quantum data center 2. The communication unit 140 communicates information with relay nodes 10 (EQRR10b, IQR10c, etc.) outside the quantum data center 2 via the classical Internet CN2.

[0059] The communication unit 140 transmits various types of information. The communication unit 140 transmits classical information to other components. The communication unit 140 receives various types of information. The communication unit 140 receives classical information from other components.

[0060] For example, the quantum function unit 150 is a component corresponding to a portion (quantum computer unit) realized by a quantum computer. In FIG. 2, the quantum function unit 150 has a quantum memory unit 160, a quantum control unit 170, and a quantum communication unit 180. Note that each unit, such as the quantum memory unit 160, the quantum control unit 170, and the quantum communication unit 180, is divided according to its function, and may have a common hardware configuration. For example, the quantum memory unit 160 and the quantum control unit 170 may be realized by a QPU.

[0061] The quantum memory unit 160 functions as a memory (quantum memory) capable of retaining the state of quantum bits. The quantum memory unit 160 stores quantum information. For example, the quantum memory unit 160 stores various types of quantum information used in processing related to each of the first to ninth tasks described below. For example, the quantum memory unit 160 stores the state of quantum entanglement.

[0062] The quantum control unit 170 may be a processor that performs quantum calculations (quantum processor), etc. The quantum control unit 170 performs processing using information received from other components. The quantum control unit 170 performs processing using information stored in the quantum memory unit 160. The quantum control unit 170 acquires various pieces of information from other components or the quantum memory unit 160.

[0063] The quantum control unit 170 executes various processes related to quantum functions. The quantum control unit 170 executes quantum computation. For example, the quantum control unit 170 executes processes related to quantum functions among the processes related to each of the first to ninth tasks described below.

[0064] The quantum communication unit 180 is realized by, for example, a quantum NIC. The quantum communication unit 180 is connected to the quantum network QN by wire or wirelessly and communicates information with other components. For example, the quantum communication unit 180 communicates quantum information with other components.

[0065] The quantum communication unit 180 is connected to the quantum intranet QN1 by wire or wirelessly, and communicates information with components within the quantum data center 2. The quantum communication unit 180 communicates information with relay nodes 10 (QRR 10a, etc.), QPD 20, etc. within the quantum data center 2 via the quantum intranet QN1.

[0066] Furthermore, the quantum communication unit 180 is connected to the quantum internet QN2 by wire or wirelessly, and communicates information with components outside the quantum data center 2. The quantum communication unit 180 communicates information with relay nodes 10 (EQRR10b, IQR10c, etc.) outside the quantum data center 2 via the quantum internet QN2.

[0067] The quantum communication unit 180 transmits various types of information. The quantum communication unit 180 transmits quantum information to other components. The quantum communication unit 180 receives various types of information. The quantum communication unit 180 receives quantum information from other components.

[0068] The quantum function unit 150 may have a function as a classical computer for controlling quantum computation in the quantum function unit 150. In this case, the quantum function unit 150 may function as a classical control unit that transmits control signals and the like to the quantum control unit 170 and acquires processing results such as calculation results (measurement results) by the quantum function unit 150 from the quantum function unit 150. In this case, the quantum function unit 150 may communicate classical information with the classical function unit 110 via the classical control unit.

[0069] The above-described configuration is one example, and the gateway device 100 is not limited to a configuration having the classical function unit 110 and the quantum function unit 150 as an integrated device, and may have any configuration, such as a configuration in which the classical function unit 110 and the quantum function unit 150 are distributed and connected to enable communication between them. In this way, the classical function unit 110 and the quantum function unit 150 do not have to be realized by a single computer (device), but may be realized by being distributed across multiple computers (devices) connected by a network.

[0070] [2-3. Configuration example of other components (quantum nodes)] Here, the configuration of quantum nodes such as the relay node 10 and QPD 20, which are components other than the gateway device 100, will be described. Below, a configuration example in which a quantum node has both classical and quantum functions will be described, using the relay node 10 as an example. Note that explanations of points similar to those described above will be omitted as appropriate.

[0071] The relay node 10 has a classical function unit and a quantum function unit. For example, the classical function unit and the quantum function unit are connected to each other so that information can be exchanged between them via a communication path using any configuration such as an I / O adapter. The classical function unit of the relay node 10 has a memory unit, a control unit, and a communication unit.

[0072] The storage unit stores various types of information using classical memory. The storage unit is realized by, for example, a semiconductor memory element such as RAM or flash memory, or a storage device such as a hard disk or optical disk. The storage unit stores various types of information used in processing. The storage unit stores classical information. For example, the storage unit stores various types of classical information used in processing related to each of the first to ninth tasks described below.

[0073] The control unit may be a processor (classical processor) that performs classical calculations, a circuit, etc. The control unit is realized by, for example, a CPU, an MPU, a GPU, etc., executing a program stored inside the relay node 10 using a RAM or the like as a work area. The control unit is also realized by, for example, an integrated circuit such as an ASIC or an FPGA.

[0074] The control unit executes processing using information received from other components. The control unit executes processing using information stored in the storage unit. The control unit acquires various pieces of information from other components or the storage unit.

[0075] The control unit executes various processes related to the classical functions. The control unit executes classical computation. For example, the control unit executes processes related to the classical functions among the processes related to each of the first to ninth tasks described below. For example, the control unit executes processes related to each task using various information such as a routing table and thresholds stored in the storage unit.

[0076] The control unit may control the quantum function unit. In this case, the control unit may transmit a control signal or the like to the quantum function unit and obtain a processing result such as a calculation result (measurement result) by the quantum function unit from the quantum function unit.

[0077] The communication unit is realized by, for example, a NIC. The communication unit is connected to the classical network CN by wire or wirelessly and communicates information with other components. For example, the communication unit communicates classical information with other components such as the gateway device 100.

[0078] When the relay node 10 is the QRR 10a, the communication unit is connected to the classical intranet CN1 by wire or wirelessly, and communicates information with components in the quantum data center 2. The communication unit communicates information with the relay nodes 10 (QRR 10a, etc.), QPD 20, etc. in the quantum data center 2 via the classical intranet CN1.

[0079] Furthermore, when the relay node 10 is EQRR10b or IQR10c, the communication unit is connected to the classical Internet CN2 by wire or wirelessly, and communicates information with components outside the quantum data center 2. The communication unit communicates information with relay nodes 10 (EQRR10b or IQR10c, etc.) outside the quantum data center 2 via the classical Internet CN2.

[0080] The communication unit transmits various types of information. The communication unit transmits classical information to other components. The communication unit receives various types of information. The communication unit receives classical information from other components.

[0081] The quantum function unit of the relay node 10 includes a quantum memory unit, a quantum control unit, and a quantum communication unit. Note that each unit, such as the quantum memory unit, quantum control unit, and quantum communication unit, is divided according to its function, and may have a common hardware configuration. For example, the quantum memory unit and quantum control unit may be realized by a QPU.

[0082] The quantum memory unit functions as a memory (quantum memory) capable of retaining the state of quantum bits. The quantum memory unit stores quantum information. For example, the quantum memory unit stores various types of quantum information used in processing related to each of the first to ninth tasks described below. For example, the quantum memory unit stores the state of quantum entanglement.

[0083] The quantum control unit may be a processor that performs quantum calculations (quantum processor), etc. The quantum control unit executes processing using information received from other components. The quantum control unit executes processing using information stored in the quantum memory unit. The quantum control unit acquires various pieces of information from other components or the quantum memory unit.

[0084] The quantum control unit executes various processes related to quantum functions. The quantum control unit executes quantum computation. For example, the quantum control unit executes processes related to quantum functions among the processes related to each of the first to ninth tasks described below.

[0085] The quantum communication unit is realized by, for example, a quantum NIC. The quantum communication unit is connected to the quantum network QN via a wired or wireless connection and communicates information with other components. For example, the quantum communication unit communicates quantum information with other components such as the gateway device 100.

[0086] When the relay node 10 is the QRR 10a, the quantum communication unit is connected to the quantum intranet QN1 by wire or wirelessly, and communicates information with components in the quantum data center 2. The quantum communication unit communicates information with the relay nodes 10 (QRR 10a, etc.), QPD 20, etc. in the quantum data center 2 via the quantum intranet QN1.

[0087] Furthermore, when the relay node 10 is EQRR10b or IQR10c, the quantum communication unit is connected to the quantum internet QN2 by wire or wirelessly, and communicates information with components outside the quantum data center 2. The quantum communication unit communicates information with relay nodes 10 (EQRR10b or IQR10c, etc.) outside the quantum data center 2 via the quantum internet QN2.

[0088] The quantum communication unit transmits various types of information. The quantum communication unit transmits quantum information to other components. The quantum communication unit receives various types of information. The quantum communication unit receives quantum information from other components.

[0089] The quantum function unit may have a function as a classical computer for controlling quantum computation in the quantum function unit. In this case, the quantum function unit may function as a classical control unit that transmits control signals and the like to the quantum control unit and acquires processing results such as computation results (measurement results) by the quantum function unit from the quantum function unit. In this case, the quantum function unit may communicate classical information with the classical function unit via the classical control unit.

[0090] The above-described configuration is an example, and the relay node 10 is not limited to a configuration having a classical function unit and a quantum function unit as an integrated device, and may have any configuration, such as a configuration in which the classical function unit and the quantum function unit are distributed and connected to enable communication between them. In this way, the classical function unit and the quantum function unit do not have to be realized by a single computer (device), but may be distributed and realized on multiple computers (devices) connected by a network. Furthermore, the QPD 20, which is the main processing unit for distributed quantum computing, also has a classical function unit and a quantum function unit, like the relay node 10, and performs desired functions.

[0091] [3. Tasks and Processing Examples] Based on the above content, processing examples executed by the information processing system 1 including the gateway device 100 and the like will now be described. Below, the flow of processing executed by the information processing system 1 for each of the first to ninth tasks will be described, but the processes may be combined in any appropriate manner as long as they can be executed in combination. Furthermore, depending on the device configuration included in the information processing system 1, the processes described below may be performed by any device included in the information processing system 1 that is capable of performing the process, not limited to the processing entities shown in each figure. Note that explanations of points similar to those described above will be omitted as appropriate.

[0092] [3-1. First Task (Routing within a Quantum Data Center)] [3-1-1. Overview of the First Task] First, an overview of the first task will be described. Note that explanations of points similar to those described above will be omitted where appropriate. The first task is a task related to routing within a quantum data center. An important point in the first task is to select a route that satisfies the computational resources required for job execution. Another important point in the first task is that the routing algorithm and policy are essentially not an issue. Another important point in the first task is that the cost of the quantum link is added as the link cost.

[0093] The link cost here can be any value used in routing such as network bandwidth, and in the case of quantum-related link costs, the generation rate of Bell states, fidelity, etc. Also, for example, a key point in the first task is that if internal information can be completely monitored, the topology is completely known, and therefore individual nodes do not need to participate in routing.

[0094] The first task may also assume the following: For example, the QGW interacts (communicates) with clients as an end node (e.g., a component at the interface between the inside and outside of the quantum data center). For example, multiple quantum nodes (e.g., quantum computers) are clustered behind the QGW (inside the quantum data center). For example, there is a 1:1 correspondence between the quantum topology and the classical topology.

[0095] 3-1-2. Example of Processing Related to First Task An example of processing related to the first task will now be described with reference to Fig. 3 and Fig. 4. Fig. 3 and Fig. 4 are sequence diagrams showing an example of processing related to the first task. The information processing system 1 executes the following processing related to the first task.

[0096] [3-1-2-1. Distributed Routing] First, an example of the specific processing shown in Fig. 3 will be described. Fig. 3 shows an example of distributed routing processing, in which each repeater manages a routing table in a distributed manner, and forwards messages and generates quantum entanglement based on the routing table.

[0097] 3, in the information processing system 1, the QPD 20 and the QRR 10a perform connection-related processing (step S101). For example, the QPD 20 and the QRR 10a, which is an adjacent node of the QPD 20, perform connection-related processing. In FIG. 3, the QPD 20 confirms the connection with the QRR 10a (step S102). Then, the QRR 10a notifies the QPD 20 of connection completion (step S103). In the above processing, for example, when the QPD 20 connects to an adjacent node and starts up, it sends a connection confirmation message to the adjacent node. The adjacent node that receives the connection confirmation message sends a connection completion message to the QPD 20. Note that the above processing may also be a message exchange at the start of a general classical routing algorithm, such as a Hello packet in OSPF (Open Shortest Path First).

[0098] When calculating link costs based on quantum states, the information processing system 1 executes steps S104 to S107 shown in branch CJ11. First, the QPD 20 creates a benchmark job (step S104). For example, the benchmark job may be a remote state verification such as quantum tomography between two nodes. For example, quantum tomography is a method for estimating quantum states. For example, the QPD 20 performs tomography or other benchmarks with adjacent nodes, but this may not be necessary if the number of hops is used as the cost.

[0099] The QPD 20 transmits the benchmark plan to the QRR 10a (step S105). Then, the QRR 10a notifies the QPD 20 of the acceptance of the benchmark plan (step S106). The QPD 20 and the QRR 10a execute a link benchmark job (step S107).

[0100] Benchmark jobs are disclosed in the following related literature: Eisert, Jens, et al. "Quantum certification and benchmarking." Nature Reviews Physics 2.7 (2020): 382-390. Bendersky, Ariel, Fernando Pastawski, and Juan Pablo Paz. "Selective and efficient estimation of parameters for quantum process tomography." Physical review letters 100.19 (2008): 190403.

[0101] Furthermore, quantum benchmark jobs and cost definitions, for example for link-local costs, are disclosed in the following literature: Van Meter, Rodney, et al. "Path selection for quantum repeater networks." Networking Science 3 (2013): 82-95.

[0102] Then, the QPD 20 and the QRR 10a calculate the link cost (step S108). For example, the QRR 10a calculates the link cost. The QRR 10a updates the link cost (step S109). The QRR 10a then transmits a link cost update message to the QGW 100 (step S110). For example, the QRR 10a transmits the calculated link cost to the QGW 100 as a link cost update message. The above process may be the same as a normal classical routing table update method. For example, each node in the QDC #1 sequentially updates the link cost, and the link cost is updated up to the QGW 100.

[0103] As a result, the link costs between the nodes in the QDC#1 are updated in the information processing system 1. For example, the QGW 100 updates the routing table based on the information about the link costs between the nodes described above.

[0104] In the information processing system 1, the CLT 30 transmits a request to the QGW 100 (step S111). For example, the CLT 30 transmits the request to the QGW 100 via the quantum internet QN2. For example, the QGW 100 receives a request (message) from the CLT 30, such as a classical client.

[0105] Then, the QGW 100 refers to the routing table (step S112) and forwards the job request to the QRR 10a (step S113). For example, the QGW 100 forwards the job request to the QRR 10a of the adjacent node based on the routing table. For example, upon receiving a request from the CLT 30, the QGW 100 refers to the routing table and forwards the request to the optimal path.

[0106] [3-1-2-2. Centralized Routing] Next, an example of specific processing shown in Fig. 4 will be described. Fig. 4 shows an example of centralized routing processing. Note that in Fig. 4, the QRR included in QDC#1 will be referred to as QRR 10a-1, and the New QRR newly added to QDC#1 will be referred to as QRR 10a-2, but when no particular distinction is made, they will be referred to as QRR 10a.

[0107] In FIG. 4, in the information processing system 1, the QGW 100 functions as a network controller. For example, the QGW 100 may function similarly to a normal classical network controller. The QGW 100 requests the QRR 10a-1 to acquire topology information, etc., and acquires the topology information, etc., from the QRR 10a-1 (step S201). The QGW 100 requests the QPD 20 to acquire topology information, etc., and acquires the topology information, etc., from the QPD 20 (step S202). For example, the QGW 100 acquires topology information and information regarding each link cost when it is started up as a network controller. Note that the QGW 100 may set all of the routing tables, link costs, etc., of each node when the network is started up, and forward requests based on the set link costs and routing tables.

[0108] In the information processing system 1, the CLT 30 transmits a request to the QGW 100 (step S203). The QGW 100 then acquires property information (step S204) and designs a route (step S205). For example, the QGW 100 receives the request via classical communication. The QGW 100 acquires the property information by reading a header, etc. For example, the QGW 100 adds necessary header information to the request from the CLT 30 based on specific properties such as billing access and application type.

[0109] Then, in the information processing system 1, when bandwidth reservation is necessary, the processes of steps S206 and S207 shown in branch CJ21 are executed. For example, the QGW 100 reserves quantum resources on the route as necessary. The QGW 100 reserves the communication channel bandwidth for the QRR 10a-1 (step S206). The QGW 100 also reserves the communication channel bandwidth for the QPD 20 (step S207). Note that this may be an extension (similar process) of the classic QoS (Quality of Service). For example, the QoS may be quality requirements such as bandwidth and clock applied to a specific application.

[0110] Then, in the information processing system 1, the QGW 100 and the QRR 10a-1 start generating quantum entanglement (step S208). For example, the QGW 100 and the QRR 10a-1, which is an adjacent node of the QGW 100, start generating quantum entanglement. The adjacent QRR 10a-1 also starts generating quantum entanglement (step S209). For example, the QRR 10a-1, which is adjacent on the route from the QGW 100 to the QPD 20, starts generating quantum entanglement. Then, the QRR 10a-1 and the QPD 20 start generating quantum entanglement (step S210). For example, the QPD 20 and the QRR 10a-1, which is an adjacent node of the QPD 20, start generating quantum entanglement.

[0111] The creation of quantum entanglement is disclosed in the following related literature: Chakraborty, Kaushik, et al. "Entanglement distribution in a quantum network: A multicommodity flow-based approach." IEEE Transactions on Quantum Engineering 1 (2020): 1-21. Caleffi, Marcello. "Optimal routing for quantum networks." IEEE Access 5 (2017): 22299-22312. Schoute, Eddie, et al. "Shortcuts to quantum network routing." arXiv preprint arXiv:1610.05238 (2016). Kozlowski, Wojciech, Axel Dahlberg, and Stephanie Wehner. "Designing a quantum network protocol." Proceedings of the 16th international conference on emerging networking experiments and technologies. 2020.

[0112] Furthermore, in the information processing system 1, when there is an update to the topology information, such as the addition of a new router, the processes of steps S211 and S212 shown after condition CJ22 are executed. For example, the QRR 10a-2, which is a new QRR newly added to the QDC #1, notifies the QGW 100 of the topology update (step S211). The QGW 100 updates the topology information (step S212). For example, when there is an update to the topology, the QGW 100 updates information such as the topology information and link costs.

[0113] As described above, by performing routing within the quantum data center 2 in the first task, the gateway device 100 can select optimal routing between the QPD 20 and the QGW 100. Therefore, the gateway device 100 can enable proper operation of the quantum network. For example, the gateway device 100 (QGW 100) receives information indicating the communication quality between a quantum node and other quantum nodes calculated by a quantum node in the quantum intranet, constructs a routing table for the quantum intranet, receives a request from a node in the quantum internet, references the routing table for the quantum intranet, and transmits the request to a quantum node in the quantum intranet based on the referenced routing table.

[0114] [3-2. Second Task (Establishing Trust with Client)] [3-2-1. Overview of the Second Task] Next, an overview of the second task will be explained. Note that explanations of points similar to those described above, such as the contents explained in other tasks, will be omitted as appropriate. The second task is a task related to establishing trust with the client. Key points in the second task include defining a protocol that can guarantee that the destination of the CLT has appropriate computing power and is trustworthy.

[0115] Furthermore, the second task may have the following assumptions: For example, trust establishment may include classical trust establishment, such as verifying the authenticity of a message or a sender, and quantum trust establishment, such as proving the authenticity of a generated state.

[0116] [3-2-2. Processing Example Related to Second Task] Next, a processing example related to the second task will be described with reference to Fig. 5 to Fig. 8. Fig. 5 to Fig. 8 are sequence diagrams showing an example of processing related to the second task. The information processing system 1 executes the following processing related to the second task.

[0117] [3-2-2-1. Classical Trust Establishment] First, an example of classical trust establishment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 shows an example of a specific process when quantum key distribution is not used. Fig. 6 shows an example of a specific process when quantum entanglement-based quantum key distribution is used.

[0118] 5 , in the information processing system 1, the QGW 100 generates a key pair (step S301). The CA 40 issues a certificate for the public key to the QGW 100 (step S302). For example, the QGW 100 requests the CA 40 to issue a certificate for the public key, and the CA 40, upon receiving the request, issues a certificate for the public key of the QGW 100.

[0119] The CLT 30 encrypts the message using the public key of the QGW 100 (step S303). The CLT 30 encrypts the message using the public key of the QGW 100 obtained by any means. For example, the CLT 30 may request the QGW 100 to provide the public key, and the QGW 100, upon receiving the request, may transmit the public key to the CLT 30.

[0120] The use of public-key cryptosystems is disclosed in the following related literature, for example: Rivest, Ronald L., Adi Shamir, and Leonard Adleman. "A method for obtaining digital signatures and public-key cryptosystems." Communications of the ACM 21.2 (1978): 120-126.

[0121] The CLT 30 transmits the encrypted message to the QGW 100 (step S304). The QGW 100 then decrypts the message using a private key (step S305). For example, the QGW 100 decrypts the message received from the CLT 30 using a private key corresponding to the public key used by the CLT 30 for encryption.

[0122] In this way, when quantum key distribution is not used, in the information processing system 1, the QGW 100 issues a certificate for its own public key. Then, the CLT 30 encrypts a message using the public key of the QGW 100. Then, the QGW 100 decrypts the encrypted message using the private key.

[0123] 6, in the information processing system 1, the CLT 30 transmits an entanglement generation request to the EQRR 10b (step S401). For example, the CLT 30 transmits the request for quantum entanglement generation to the EQRR 10b via the quantum internet QN2. Upon receiving the entanglement generation request, the EQRR 10b forwards the entanglement generation request to the QGW 100 (step S402).

[0124] Upon receiving the entanglement generation request, the QGW 100 notifies the EQRR 10b of the entanglement generation task (step S403). For example, the QGW 100 notifies the EQRR 10b on the route between the requesting CLT 30 and the QGW 100 of the entanglement generation task. The QGW 100 also notifies the CLT 30 of the entanglement generation task (step S404). For example, the QGW 100 notifies the requesting CLT 30 of the entanglement generation task.

[0125] The QGW 100, the EQRR 10b, and the CLT 30 start performing quantum entanglement generation (step S405). As a result, the QGW 100, the EQRR 10b, and the CLT 30 generate quantum entanglement (step S406). For example, the QGW 100, the CLT 30, and the EQRR 10b on the route between the CLT 30 and the QGW 100 perform quantum entanglement generation and generate quantum entanglement.

[0126] Then, the QGW 100, the EQRR 10b, and the CLT 30 execute quantum key distribution (step S407). For example, the QGW 100 distributes (transmits) a key (such as a message shared key) to be used for encryption to the CLT 30 using quantum entanglement. The CLT 30 encrypts the message using the message shared key provided by the QGW 100 (step S408).

[0127] Quantum key distribution techniques are disclosed in the following related documents: Ekert, Artur K. "Quantum cryptography based on Bell's theorem." Physical review letters 67.6 (1991): 661. Ribordy, Gregoire, et al. "Long-distance entanglement-based quantum key distribution." Physical Review A 63.1 (2000): 012309.

[0128] The CLT 30 transmits the encrypted message to the QGW 100 (step S409). The QGW 100 then decrypts the message using a private key (step S410). For example, the QGW 100 decrypts the message received from the CLT 30 using a key corresponding to the key used by the CLT 30 for encryption.

[0129] In this way, when quantum key distribution is used, in the information processing system 1, the CLT 30 sends a request to the QGW 100 to generate quantum entanglement. If the QGW 100 accepts the entanglement generation, it returns the generation job. Then, the CLT 30, the QGW 100, and the EQRR 10b generate quantum entanglement between the CLT 30 and the QGW 100. Then, the CLT 30 and the QGW 100 use the entanglement to share the key.

[0130] [3-2-2-2. Establishing Trust in a Quantum State] Next, an example of establishing trust in a quantum state will be described with reference to Figs. 7 and 8. For example, the establishment of trust in a quantum state is performed by verifying that the generated quantum state is a correct quantum state. Fig. 7 shows an example of a specific process for verifying a communication path. Fig. 8 shows an example of a specific process for computer verification.

[0131] First, the process related to communication path verification in FIG. 7 will be described. In FIG. 7, when preprocessing is performed in the information processing system 1, the process of step S501 shown in branch CJ51 is executed. When preprocessing is performed, the QGW 100 shares the sequence number of the quantum entanglement used for verification with the CLT 30 (step S501). For example, the QGW 100 may share information indicating the sequence number of the quantum entanglement used for verification with the CLT 30 by transmitting information to the CLT 30 indicating the sequence number. For example, the QGW 100 and the CLT 30 periodically share the sequence number indicating which quantum entanglement is to be used for verification. Note that the frequency may be determined based on any criteria such as a state verification protocol.

[0132] The information processing system 1 then executes a loop process for generating quantum entanglement, shown as loop IR51. First, the QGW 100, the EQRR 10b, and the CLT 30 generate quantum entanglement (step S502). For example, the QGW 100, the CLT 30, and the EQRR 10b on the route between the CLT 30 and the QGW 100 execute quantum entanglement generation to generate quantum entanglement.

[0133] If the verification sequence number is equal to the verification sequence number, the information processing system 1 executes steps S503 to S505 shown in branch CJ52. The QGW 100, EQRR 10b, and CLT 30 perform quantum state verification (step S503). For example, the information processing system 1 executes the state verification protocol using a few percent of the generated quantum entanglement. The QGW 100 then stores the measurement results (step S504). The CLT 30 also stores the measurement results (step S505).

[0134] Quantum state verification is disclosed in the following related literature, for example: ・Pappa, Anna, et al. "Multipartite entanglement verification resistant against dishonest parties." Physical review letters 108.26 (2012): 260502. ・Li, Zihao, Yun-Guang Han, and Huangjun Zhu. "Efficient verification of bipartite pure states." Physical Review A 100.3 (2019): 032316. ・Wang, Kun, and Masahito Hayashi. "Optimal verification of two-qubit pure states." Physical Review A 100.3 (2019): 032315.

[0135] On the other hand, in the information processing system 1, in other cases, i.e., when the sequence number is not equal to the verification sequence number, the process of step S506 shown in branch CJ52 is executed. The QGW 100, EQRR 10b, and CLT 30 execute normal tasks (step S506). The QGW 100, EQRR 10b, and CLT 30 may execute applications such as DQC (Data Quality Control).

[0136] Then, the QGW 100 transmits the verification result to the CLT 30 (step S507). Also, the CLT 30 transmits the verification result to the QGW 100 (step S508).

[0137] When an abnormality is detected in the information processing system 1, the processes of steps S509 and S510 shown in branch CJ53 are executed. When an abnormality is detected, the QGW 100 and the CLT 30 cut off the connection (step S509). When an abnormality is detected, for example, the QGW 100 cuts off communication with the CLT 30. Then, the CLT 30 performs rerouting (step S510). For example, when an abnormality is detected in an S value related to the Bell state (e.g., a value in Bell's inequality), the CLT 30 and the QGW 100 cut off communication once, and the CLT 30 communicates again using a different route.

[0138] On the other hand, in the information processing system 1, if there is no abnormality, that is, if no abnormality is detected, the process of step S511 shown in branch CJ53 is executed. If there is no abnormality, the CLT 30 continues execution (step S511). For example, if there is a normal state, the QGW 100 and the CLT 30 continue processing.

[0139] Next, the process related to computer verification in FIG. 8 will be described. In FIG. 8, in the information processing system 1, the CLT 30 randomly creates verification jobs (step S601). Note that the verification jobs here can be any job, such as a matrix calculation or a chemical basis, as long as the calculation performance can be guaranteed. For example, the verification jobs may be jobs with a processing load that is difficult to process using classical functions (e.g., a calculation amount of 50 or more quantum bits). For example, the CLT 30 may randomly change some of the jobs to be sent to verification jobs.

[0140] Verification jobs are disclosed in the following related literature: Gheorghiu, Alexandru, and Thomas Vidick. "Computationally-secure and composable remote state preparation." 2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS). IEEE, 2019. Knorzer, Johannes, Daniel Malz, and J. Ignacio Cirac. "Cross-Platform Verification in Quantum Networks." arXiv preprint arXiv:2212.07789 (2022).

[0141] Then, the CLT 30 transmits the verification job to the QGW 100 of the quantum data center 2 (step S602). The QGW 100 and the QPD 20 that have received the verification job execute the received verification job (step S603).

[0142] In the information processing system 1, when a quantum state is used for verification, the processes of steps S604 to S606 shown in branch CJ61 are executed. When a quantum state is used for verification, the QGW 100 generates quantum entanglement (step S604). When a quantum state is used for verification, for example, the QGW 100 and the CLT 30 execute quantum entanglement generation to generate quantum entanglement. Then, the QGW 100 transmits the verification result state (step S605). For example, the QGW 100 transmits the verification result state to the CLT 30. The CLT 30 verifies the final state (step S606). For example, the QGW 100 and the CLT 30 generate entanglement between end nodes and measure the transmitted quantum state.

[0143] On the other hand, in the information processing system 1, when the results are transmitted via classical communication, i.e., when the quantum state is not used for verification, the processes of steps S607 and S608 shown in branch CJ61 are executed. When the results are transmitted via classical communication, the QGW 100 transmits the execution results (step S607). For example, the QGW 100 transmits the execution results to the CLT 30. The CLT 30 verifies the calculation results (step S608). For example, the CLT 30 compares the calculation results with the expected calculation results, and if the calculation results differ significantly, the communication is interrupted.

[0144] In addition to the above, the second task is also disclosed in the following literature: Satoh, Takahiko, et al. "The network impact of hijacking a quantum repeater." Quantum Science and Technology 3.3 (2018): 034008

[0145] As described above, by establishing trust with the client in the second task, the gateway device 100 can ensure high reliability, which is an advantage of the quantum network. Therefore, the gateway device 100 can enable proper operation of the quantum network. For example, at the stage of starting communication of quantum information, the gateway device 100 generates quantum entanglement with a quantum node in the quantum internet, measures the quality of the quantum entanglement, and continues communication if the measured quality is normal, but cuts off communication if the measured quality is abnormal.

[0146] [3-3. Third Task (Participation in the Quantum Internet)] [3-3-1. Overview of the Third Task] Next, an overview of the third task will be provided. Note that explanations of points similar to those described above, such as the content explained in other tasks, will be omitted as appropriate. The third task is a task related to participation in the quantum internet. Key points in the third task include being able to cooperate with other quantum networks while satisfying the policies that should be referenced.

[0147] The third task may assume the following: For example, a new quantum data center attempts to connect to the quantum internet. For example, it is assumed that the physical link has already been established. For example, it is assumed that the link cost with an external router is unknown. For example, it is assumed that the QGW has information about connectable hosts within the quantum data center.

[0148] [3-3-2. Example of Processing Related to Third Task] Next, an example of processing related to the third task will be described with reference to Fig. 9. Fig. 9 is a sequence diagram showing an example of processing related to the third task. The information processing system 1 executes the following processing related to the third task.

[0149] 9 is an external quantum node (relay node 10 such as a quantum router) adjacent to the QGW 100, and EQRR 10b-2 is an external quantum node (relay node 10) not adjacent to the QGW 100. For example, EQRR 10b-1 is the leftmost EQRR 10b of the seven EQRRs 10b shown in FIG. 1, and EQRR 10b-2 may be another EQRR 10b (for example, the rightmost EQRR 10b).

[0150] 9 illustrates an example in which an IQR 10c is placed between the QGW 100 and an adjacent node, EQRR 10b-1. In this case, in FIG. 1, the IQR 10c is placed between the leftmost EQRR 10b of the seven EQRRs 10b and the QGW 100, and is connected to the leftmost EQRR 10b and the QGW 100 via the quantum internet QN2. For example, the IQR 10c is a component that has the function of a repeater outside the quantum data center 2. For example, the IQR 10c communicates (transfers) quantum states (quantum information) with other components using quantum teleportation techniques based on quantum entanglement swapping and classical communication.

[0151] The number of IQR 10c is not limited to one, and may be any number. The IQR 10c in Fig. 1 may be an EQRR 10b. In this way, the configuration in which the nodes are connected across the IQR 10c that performs relay as a repeater may also be adjacent nodes, and the leftmost EQRR 10b of the seven EQRRs 10b is the adjacent node of the gateway device 100.

[0152] An example of participation in the quantum internet will be described below using FIG. 9. In FIG. 9, in the information processing system 1, the QGW 100 and the EQRR 10b-1 perform link-up processing (step S701). The QGW 100 confirms the connection (OPEN) with the EQRR 10b-1 (step S702). For example, the QGW 100 may perform processing similar to an OPEN message of the Border Gateway Protocol (BGP). For example, the QGW 100 connects to the EQRR 10b-1 and performs processing to enable communication with the EQRR 10b-1. Then, the EQRR 10b-1 notifies the QGW 100 of the completion of the connection and shares existing route information (UPDATE) (step S703).

[0153] Regarding the above process, the protocol for routing between autonomous systems (ASs) used in classical communication is disclosed in the following document, for example: Rekhter, Yakov, Tony Li, and Susan Hares. A border gateway protocol 4 (BGP-4). No. rfc4271. 2006.

[0154] In the information processing system 1, when the inter-AS link cost (quantum cost) is required, the processes of steps S704 to S718 shown in branch CJ71 are executed. The QGW 100 creates a link cost calculation job (step S704). Then, the QGW 100 transmits a benchmark job (step S705). For example, the QGW 100 transmits the benchmark job to the EQRR 10b-1.

[0155] The EQRR 10b-1 verifies the benchmark job (step S706). Then, the EQRR 10b-1 returns a response (step S707). For example, the EQRR 10b-1 transmits the verification result (response) of the benchmark job to the QGW 100.

[0156] The QGW 100 sends a link quantum entanglement generation request to the IQR 10c (step S708). For example, the QGW 100 sends a request to the IQR 10c, which is located between the QGW 100 and the EQRR 10b-1, to request that the IQR 10c generate quantum entanglement between the QGW 100 and the EQRR 10b-1.

[0157] Upon receiving the request, the IQR 10c starts quantum entanglement generation (step S709). For example, the IQR 10c starts quantum entanglement generation between the QGW 100 and the EQRR 10b-1. The IQR 10c then generates a quantum entangled pair with the QGW 100 (step S710), and generates a quantum entangled pair with the EQRR 10b-1 (step S711). As a result, the QGW 100, the IQR 10c, and the EQRR 10b-1 generate quantum entanglement (step S712).

[0158] Then, the QGW 100, the IQR 10c, and the EQRR 10b-1 start a benchmark job (step S713). For example, the information processing system 1 performs benchmarking when the quantum entanglement generation rate and fidelity are used for routing. In this process, the same benchmarking method as in the first task can be used, so detailed description will be omitted.

[0159] Then, the QGW 100 calculates the link cost (step S714) and updates the routing table (step S715). Also, the EQRR 10b-1 calculates the link cost (step S716) and updates the routing table (step S717). Note that the processing of steps S714 and S715 and the processing of steps S716 and S717 may be performed in parallel, or either processing may be performed first.

[0160] Then, the EQRR 10b-1 updates the routing table of the EQRR 10b-2 (step S718). For example, the EQRR 10b-1 may request the EQRR 10b-2 to update the routing table by transmitting the information of the routing table updated in step S717 to the EQRR 10b-2, and cause the EQRR 10b-2 to update the routing table.

[0161] On the other hand, in the information processing system 1, when the inter-AS link cost (quantum cost) is not taken into consideration, that is, when the inter-AS link cost is not necessary, the processes of steps S719 and S720 shown in branch CJ71 are executed. EQRR 10b-1 transmits a routing table update message to the QGW 100 (step S719). For example, EQRR 10b-1 transmits a routing table update message to the QGW 100, thereby requesting the QGW 100 to update the routing table, and causing the QGW 100 to update the routing table. EQRR 10b-1 also transmits a routing table update message to EQRR 10b-2 (step S720). For example, EQRR 10b-1 transmits a routing table update message to EQRR 10b-2, thereby requesting the EQRR 10b-2 to update the routing table, and causing EQRR 10b-2 to update the routing table.

[0162] Note that cases where link costs between ASes are not used are disclosed in the following related literature, for example: Tanizawa, Yoshimichi, Ririka Takahashi, and Alexander R. Dixon. "A routing method designed for a quantum key distribution network." 2016 Eighth International Conference on Ubiquitous and Future Networks (ICUFN). IEEE, 2016.

[0163] In this way, when processing related to participation in the quantum internet is performed in the information processing system 1, the QGW 100 transmits a message to adjacent nodes notifying them of its presence upon completion of the physical connection. The adjacent nodes that receive the message from the EQRR 10b-1 return a response confirming receipt. The QGW 100 then creates a benchmark job plan for calculating link costs and transmits it to the adjacent nodes. The adjacent nodes then receive the benchmark job plan from the EQRR 10b-1 and return a response. Based on the transmitted job, the QGW 100 then requests intermediate relays (IQR 10c) and the like to generate link states according to the agreed-upon plan. The QGW 100 and the EQRR 10b-1 then benchmark the link states and calculate the link costs. The QGW 100 and the EQRR 10b-1 then update the routing table based on the link costs.

[0164] As described above, by performing processing related to participation in the quantum internet in the third task, the gateway device 100 can enable the quantum data center to properly communicate with the CLT 30 in the quantum internet. Therefore, the gateway device 100 can enable proper operation of the quantum network. For example, the gateway device 100 transmits a message to a neighboring quantum node, receives a response from the neighboring quantum node, requests the neighboring quantum node to obtain information indicating the communication quality between the gateway device 100 and the neighboring quantum node, and obtains the information indicating the communication quality between the neighboring quantum node from the gateway device 100.

[0165] [3-4. Fourth Task (Routing Outside the Quantum Data Center)] [3-4-1. Overview of the Fourth Task] Next, an overview of the fourth task will be explained. Note that explanations of points similar to those described above, such as the contents explained in other tasks, will be omitted as appropriate. The fourth task is a task related to quantum internet routing. Key points of the fourth task include sharing information about the QGW with adjacent nodes of the QGW on the quantum internet side.

[0166] The fourth task may assume the following: For example, a new quantum router or client has been added to the quantum internet somewhere.

[0167] [3-4-2. Example of Processing Related to Fourth Task] Next, an example of processing related to the fourth task will be described with reference to Fig. 10. Fig. 10 is a sequence diagram showing an example of processing related to the fourth task. The information processing system 1 executes the following processing related to the fourth task.

[0168] 10, EQRR 10b-1 indicated as "EQRR" and EQRR 10b-2 indicated as "EQRR#2" are assumed to be external quantum nodes (relay nodes 10 such as quantum routers) adjacent to the QGW 100. In this way, FIG. 10 will be used as an example to explain the case where there are multiple adjacent nodes in the QGW 100.

[0169] An example of quantum internet routing will be described below using FIG. 10. In FIG. 10, a new router (such as a quantum node) joins the network in the information processing system 1 (step S801). Then, the EQRR 10b-1 updates the routing table (step S802). The EQRR 10b-1 sends a routing table update message to the QGW 100 (step S803). Then, the QGW 100 updates the routing table (step S804). In this way, the EQRR 10b-1 requests the QGW 100 to update the routing table by sending a routing table update message to the QGW 100, and causes the QGW 100 to update the routing table.

[0170] In the information processing system 1, if there are multiple adjacent nodes to the QGW 100, the process of step S805 shown in branch CJ81 is executed. The QGW 100 forwards the update message (step S805). For example, the QGW 100 forwards the update message to EQRR 10b-2, which is an adjacent node other than EQRR 10b-1. For example, EQRR 10b-2, which receives the update message forwarded from the QGW 100, updates its routing table based on the received routing table update message.

[0171] In this way, when routing outside the quantum data center is performed, in the information processing system 1, the QGW 100 receives a message from its adjacent node that the route has been updated. Once the physical connection is complete, the QGW 100 sends a message to the adjacent node informing it of its existence. The QGW 100 then updates its routing table. The QGW 100 then distributes the updated routing information to other adjacent nodes.

[0172] As described above, by performing routing outside the quantum data center, i.e., routing of the quantum internet, in the fourth task, the gateway device 100 can enable appropriate routing between the gateway device 100 and the CLT 30 or between the gateway device 100 and other ASs (Autonomous Systems). Therefore, the gateway device 100 can enable appropriate operation of the quantum network. For example, the gateway device 100 receives a routing table update message transmitted in response to an update of the routing table of a neighboring quantum node, and updates its routing table based on the routing table update message of the neighboring quantum node.

[0173] [3-5. Fifth Task (Leaving the Quantum Internet)] [3-5-1. Overview of the Fifth Task] Next, an overview of the fifth task will be explained. Note that explanations of points similar to those described above, such as the contents explained in other tasks, will be omitted as appropriate. The fifth task is a task related to leaving the quantum internet. Key points of the fifth task include defining separate protocols for normal termination and abnormal termination.

[0174] Furthermore, the fifth task may assume the following: For example, the entire quantum data center leaves the quantum internet for some reason.

[0175] 11 to 13, a processing example related to the fifth task will be described. FIGS. 11 to 13 are sequence diagrams showing an example of processing related to the fifth task. The information processing system 1 executes the following processing related to the fifth task.

[0176] [3-5-2-1. Normal Departure] First, an example of normal departure will be described with reference to Fig. 11. Fig. 11 shows an example of specific processing when performing normal departure.

[0177] 11, the QGW 100 declares withdrawal (step S901) in the information processing system 1. For example, the QGW 100 transmits information indicating withdrawal from the quantum internet (for example, quantum internet QN2, etc.) to the EQRR 10b.

[0178] Upon receiving the declaration of withdrawal from the QGW 100, the EQRR 10b deletes the route to the QGW 100 from the routing table (step S902). The QGW 100 also stops the intermediate relays (step S903). For example, the QGW 100 requests the IQR 10c to stop relaying, and the relaying by the IQR 10c is stopped.

[0179] [3-5-2-2. Classical Equipment Failure] Next, an example of a classical equipment failure will be described using FIG. 12. FIG. 12 shows an example of specific processing when a classical equipment failure occurs. For example, FIG. 12 shows an example of specific processing when a failure occurs in the classical function of the QGW 100. As described above, the network manager may be a computer that functions as a network manager, or may be a human administrator. If the network manager is a human administrator, the NMG 50 shown in FIG. 12 may be a computer (e.g., a mobile terminal) used by the human administrator.

[0180] 12, in the information processing system 1, the EQRR 10b loses classical communication with the QGW 100 (step S1001). For example, the EQRR 10b loses classical communication with the QGW 100 due to a situation in which classical communication via the classical Internet CN2 is no longer possible.

[0181] The EQRR 10b, which has lost classical communication with the QGW 100, deletes the route to the QGW 100 from the routing table (step S1002). The QGW 100 also notifies the NMG 50 of the communication error (step S1003). For example, the QGW 100 notifies the NMG 50 of the communication error by sending information to the NMG 50 indicating that classical communication with the EQRR 10b is no longer possible.

[0182] Upon receiving the notification of the communication error, the NMG 50 corrects the error (step S1004). For example, if the network manager is a human administrator, the human administrator using the NMG 50 corrects the error based on the content of the communication error notification.

[0183] The QGW 100 requests the EQRR 10b to join again (step S1005). After the communication error has been corrected, the QGW 100 requests the EQRR 10b to join again. For example, the QGW 100 requests the EQRR 10b to join again in the same way as in the processing in the third task.

[0184] Quantum Device Fault] Next, an example of a quantum device fault will be described with reference to Fig. 13. Fig. 13 shows an example of a specific process to be performed when a quantum device fault occurs.

[0185] 13, the QGW 100 and the EQRR 10b experience a quantum state generation anomaly (step S1101) in the information processing system 1. Then, the EQRR 10b detects the state generation anomaly (step S1102).

[0186] Upon detecting the quantum state generation anomaly with the QGW 100, the EQRR 10b deletes the route to the QGW 100 (step S1103). As a result, the EQRR 10b updates the routing table (step S1104). The EQRR 10b also notifies the QGW 100 of the quantum state generation anomaly (step S1105).

[0187] Upon receiving the notification of the quantum state generation abnormality, the QGW 100 notifies the NMG 50 of the error (step S1106). For example, the QGW 100 notifies the NMG 50 of the error regarding the quantum state generation by transmitting information indicating that the quantum state generation between the QGW 100 and the EQRR 10b has become abnormal.

[0188] Upon receiving the error notification, the NMG 50 corrects the error for the QGW 100 (step S1107). The NMG 50 also corrects the error for the IQR 10c (step S1108). For example, if the network manager is a human administrator, the human administrator using the NMG 50 corrects the error for the QGW 100 and the IQR 10c arranged between the QGW 100 and the EQRR 10b based on the content of the error notification.

[0189] The QGW 100 requests the EQRR 10b to join again (step S1109). After the error correction is completed, the QGW 100 requests the EQRR 10b to join again. For example, the QGW 100 requests the EQRR 10b to join again in the same manner as in the processing in the third task.

[0190] In this way, when leaving the quantum internet, the information processing system 1 executes various processes depending on the situation. For example, when the information processing system 1 leaves the quantum internet through a normal process such as maintenance, the QGW 100 sends a message declaring the departure to adjacent nodes. The adjacent nodes delete the route to QDC#1 (such as the QGW 100) and update their routing tables. The QGW 100 shuts down any repeaters (such as the IQR 10c) that are generating entanglement between the adjacent nodes.

[0191] Furthermore, for example, in the case of information processing system 1, if a node suddenly leaves the quantum internet due to an abnormal termination caused by a classical equipment failure or the like, the adjacent node loses communication with the QGW 100, and the adjacent node that has lost communication excludes QDC#1 (QGW 100, etc.) from its routing table. When the QGW 100 confirms that there is an abnormality in communication, it outputs an error and requests participation again once the network manager has made the correction.

[0192] Furthermore, for example, in the information processing system 1, if a quantum equipment failure occurs and entanglement is not generated between the QGW 100 and an adjacent node, the adjacent node deletes the route to the QGW 100 from its routing table and sends a message to the QGW 100 informing it of a quantum state generation anomaly. The QGW 100 receives the message and outputs an error message. Once the network manager has confirmed and corrected the error, the QGW 100 sends a message to the adjacent node informing it that a benchmark will be performed. The benchmark plan is then re-performed between the adjacent node that accepted the benchmark plan and the QGW 100, and once it has been confirmed that the quantum state is being generated normally, the plan is incorporated into the routing table again. If an anomaly is detected, the QGW 100 outputs an error message again.

[0193] The fifth task is discussed in the following related literature: Gyongyosi, Laszlo, and Sandor Imre. "Adaptive routing for quantum memory failures in the quantum internet." Quantum Information Processing 18 (2019): 1-21.

[0194] As described above, by leaving the quantum internet in the fifth task, the gateway device 100 can create the appropriate routing table required in the fourth task even in the event of a failure, thereby enabling other routers (e.g., relay node 10) participating in the quantum internet to properly update their information. As a result, the CLT 30 can properly grasp the operation information of the quantum data center and take appropriate action even when the quantum data center leaves the network. Therefore, the gateway device 100 can ensure proper operation of the quantum network. For example, the gateway device 100 can receive a notification of a quantum state generation anomaly from an adjacent quantum node and notify the network manager of the error to correct the error in the quantum repeater between the adjacent quantum node and the gateway device 100.

[0195] [3-6. Sixth Task (Monitoring Internal Information)] [3-6-1. Overview of the Sixth Task] Next, an overview of the sixth task will be explained. Note that explanations of the same points as those explained above, such as the content explained in other tasks, will be omitted as appropriate. The sixth task is a task related to monitoring internal information. Key points of the sixth task include the fact that it separately defines cases where internal information is dynamically monitored and cases where it is not.

[0196] The sixth task may also assume the following: For example, internal information refers to information such as the QPD within the network boundary (intranet), link status and settings, and running tasks. For example, the QGW acts as a process on a network controller / gateway router.

[0197] [3-6-2. Processing Example Related to Sixth Task] Next, a processing example related to the sixth task will be described with reference to Fig. 14 and Fig. 15. Fig. 14 and Fig. 15 are sequence diagrams showing an example of processing related to the sixth task. The information processing system 1 executes the following processing related to the sixth task.

[0198] [3-6-2-1. Device Health Check] First, an example of a device health check will be described with reference to Fig. 14. Fig. 14 shows an example of a specific process for performing a device health check.

[0199] 14, in the information processing system 1, the QGW 100 transmits a health check message to the QPD 20 (step S1201). For example, the QGW 100 transmits a health check message requesting device health information to the QPD 20, thereby requesting device health information from the QPD 20.

[0200] The QPD 20 that receives the health check message transmits a response to the QGW 100 (step S1202). For example, the QPD 20 that receives a health check message requesting device health information transmits a response related to device health to the QGW 100. For example, the response related to device health includes information such as QPU usage rate and device health as monitoring items. For example, QPU usage rate is a rate calculated by dividing the number of quantum bits used in a quantum process by the number of available quantum bits. Furthermore, device health is information indicating whether all processes are operating normally. The monitoring items are not limited to QPU usage rate and device health, and may include any item related to device health.

[0201] If there is no response, the information processing system 1 executes the process of step S1203 shown in branch CJ121. If there is no response, the QGW 100 notifies the NMG 50 of an error (step S1203). For example, the QGW 100 transmits to the NMG 50 information indicating that there is no response from the QPD 20 to which the health check message was transmitted.

[0202] [3-6-2-2. Link Health Check] Next, an example of a link health check will be described with reference to Fig. 15. Fig. 15 shows an example of a specific process for performing a link health check.

[0203] 15 , in the information processing system 1, the QGW 100 transmits a health check message to the QPD 20 (step S1301). For example, the QGW 100 transmits a health check message requesting link health information to the QPD 20, thereby requesting link health information from the QPD 20.

[0204] The QPD 20 that has received the health check message transmits a response to the QGW 100 (step S1302). For example, the QPD 20 that has received a health check message requesting link health information transmits a response regarding link health to the QGW 100. For example, the response regarding link health includes information such as the link creation rate and average fidelity as monitoring items. For example, the link creation rate is information indicating the number of physical bell pairs per second. Furthermore, the average fidelity is the average (value) of the fidelity of the generated physical bell pairs. The monitoring items are not limited to the link creation rate and average fidelity, and may include any item related to link health.

[0205] In the information processing system 1, if there is no response or if a status generation abnormality is detected, the process of step S1303 shown in branch CJ131 is executed. If there is no response or if a status generation abnormality is detected, the QGW 100 notifies the NMG 50 of an error (step S1303). For example, the QGW 100 transmits to the NMG 50 information indicating that there is no response from the QPD 20 to which the health check message was transmitted.

[0206] In this way, when monitoring internal information, the information processing system 1 performs various processes depending on the information being monitored and the situation. For example, the information processing system 1 may utilize the monitored information. For example, if the information processing system 1 does not monitor any internal information, it may utilize information obtained by internal routing (only topology and link cost information). Furthermore, for example, when monitoring devices within a network, the information processing system 1 may perform a health check of each QPU or process within a QPU, and a device (restart if abnormally terminated). Furthermore, for example, the information processing system 1 may perform processes related to the generation rate of each link, the generation state fidelity of each link, device failure detection, rerouting, etc. Furthermore, for example, the information processing system 1 may perform processes related to QoS, routing optimization, etc. based on the utilization rate of each QPU.

[0207] Furthermore, for example, the information processing system 1 may perform the following process for the health check of each device: For example, in the information processing system 1, the QGW 100 periodically sends a message to each QPU (such as the QPD 20), and determines that the QPU (such as the QPD 20) that returns a response is normal.

[0208] Furthermore, for example, the information processing system 1 may monitor the processes of each device, and each QPU may have a resident process that monitors processes related to quantum operations, applications, etc. In this case, for example, if a process in the information processing system 1 terminates abnormally, error information and information about the corresponding client are sent to the QGW 100. The QGW 100 then sends the contents of the error to the client.

[0209] Furthermore, for example, the information processing system 1 may perform processing related to the generation rate of each link. For example, in the information processing system 1, each QPU (such as the QPD 20) constantly monitors the state generation rate calculated from the swapping record or the like, and transmits the latest generation rate to the QGW 100 when performing a health check of the QGW 100. The QGW 100 compares the difference in values ​​between the left and right repeaters of each link with the previous record, and if an abnormality is found, recalculates the route and notifies the network manager.

[0210] Furthermore, for example, the information processing system 1 may perform processing related to the fidelity of each link state. For example, the information processing system 1 uses a few percent of the generated link states for performance measurement such as tomography, and constantly updates the link fidelity. For example, the information processing system 1 feeds back the latest link fidelity to the QGW 100 during a health check or periodically, and the QGW 100 updates the link cost information.

[0211] Furthermore, for example, the information processing system 1 may perform processing related to QPU utilization rates. For example, in the information processing system 1, each QPU has a resident process that monitors the number of quantum bits in use and measures the utilization rate. For example, the information processing system 1 may feed back the latest QPU utilization rate to the QGW 100 during a health check or periodically, and based on that information, allocate tasks starting from the QPU with the lowest utilization rate.

[0212] As described above, by monitoring internal information in the sixth task, the gateway device 100 can perform effective routing, optimize network resources, and detect malfunctions, thereby enabling the gateway device 100 to ensure proper operation of the quantum network.

[0213] [3-7. Seventh Task (Communication Quality Guarantee, Resource Reservation)] [3-7-1. Overview of the Seventh Task] Next, an overview of the seventh task will be explained. Note that explanations of the same points as those explained above, such as the contents explained in other tasks, will be omitted as appropriate. The seventh task is a task related to communication quality guarantee (QoS) or resource reservation. Key points of the seventh task include the appropriate allocation of resources for each service and CLT while also ensuring the overall service quality.

[0214] The seventh task may also assume the following points. For example, resources refer to computational resources such as the generation rate of each quantum link and the available quantum bits in the QPD. For example, the QGW has the authority to reserve resources within the network, but does not negotiate resource allocation for the extranet. For example, quantum QoS may relate to the quality of a quantum application, such as the quantity and quality of quantum entanglement allocated to a certain application or low-latency feedback operations. For example, the required generation rate and fidelity threshold may vary depending on the type of quantum application. For example, the QGW is responsible for the QoS requirements for the application.

[0215] [3-7-2. Example of Processing Related to Seventh Task] Next, an example of processing related to the seventh task will be described with reference to Fig. 16. Fig. 16 is a sequence diagram showing an example of processing related to the seventh task. The information processing system 1 executes the following processing related to the seventh task.

[0216] First, an example of a specific process shown in Fig. 16 will be described. In Fig. 16, in the information processing system 1, the CLT 30 transmits a request including QoS requirements to the QGW 100 (step S1401). For example, the CLT 30 transmits the request including the QoS requirements to the QGW 100, thereby requesting the QGW 100 to provide the communication quality indicated by the QoS requirements. The QGW 100, which receives the request including the QoS requirements from the CLT 30, examines the QoS requirements (step S1402). For example, the QGW 100 examines the QoS requirements to identify the quality required by the CLT 30.

[0217] In the information processing system 1, if the QoS requirements cannot be satisfied, the process of step S1403 shown in branch CJ141 is executed. For example, if the QoS requirements cannot be satisfied, the QGW 100 notifies the CLT 30 of an error (step S1403). For example, if the QoS requirements cannot be satisfied, that is, if the QGW 100 determines that the quality specified by the QoS requirements cannot be guaranteed, the QGW 100 notifies the CLT 30 of the error by transmitting information indicating that the QoS requirements cannot be satisfied.

[0218] On the other hand, in the information processing system 1, if the QoS requirements can be satisfied, the processes of steps S1404 to S1408 are executed. First, the QGW 100 establishes a route (step S1404). For example, if the QoS requirements can be satisfied, that is, if the QGW 100 determines that the quality indicated by the QoS requirements can be guaranteed, the QGW 100 determines the QPD 20 to be used for the service to the CLT 30 and determines the routing between the QPD 20.

[0219] Then, the QGW 100 performs quantum communication scheduling between itself (the QGW 100) and the CLT 30 (step S1405). For example, the QGW 100 generates a quantum communication schedule that satisfies the QoS requirements between the QGW 100 and the CLT 30. The QGW 100 shares the schedule with the CLT 30 (step S1406). For example, the QGW 100 shares the schedule related to quantum communication with the CLT 30 by transmitting information indicating the generated quantum communication schedule to the CLT 30.

[0220] The QGW 100 reserves the quantum bandwidth for the QRR 10a-1 (step S1407).The QGW 100 also reserves the quantum processor usage and transmits the task to the QPD 20 (step S1408).

[0221] The QPD 20 and the QRR 10a-1 execute the task (step S1409). For example, the QPD 20 and the QRR 10a-1 execute the specified job (task) based on the information received from the QGW 100.

[0222] In this way, when guaranteeing communication quality and reserving resources, the information processing system 1 calculates the required resources and performs internal routing when the QGW 100 receives an application request. For example, when reserving resources required depending on the type of application, the information processing system 1 requests devices on the route to secure the required quantum bandwidth based on a table of relationships between pre-set application types and required resources.

[0223] Furthermore, for example, in the information processing system 1, if a request from a client has a QoS condition (such as a QoS requirement) set in advance, the QGW 100 verifies whether the QoS can be guaranteed. For example, in the information processing system 1, if the QoS cannot be guaranteed, the QGW 100 returns a response to the client indicating that the QoS cannot be guaranteed.

[0224] Also, for example, in the information processing system 1, in the case of an application in which synchronization with the client is important, the QGW 100 reserves a resource generation rate equivalent to the generation rate calculated from the route to the client on the path to the end node QPU (QPD20, etc.).

[0225] For example, the information processing system 1 guarantees quality when an application is executed with priority or a service is used with priority. For example, the information processing system 1 performs QoS routing for an application that imposes very high fidelity requirements.

[0226] For example, the information processing system 1 may estimate the generation rate in the quantum internet and reserve internal resources with a margin sufficient for purification and error correction. Furthermore, for example, the information processing system 1 may estimate the generation rate in the quantum internet and reserve internal resources to approach that generation rate. In this case, for example, the information processing system 1 allocates surplus resources to other connections, processes, etc. as needed to perform purification, etc. between end nodes.

[0227] Furthermore, in the information processing system 1, when setting QoS requirements, weighting may be performed based on the following points to determine how many bell pairs to allocate to each application. For example, the information processing system 1 may be able to flexibly select one or more of these from the following points.

[0228] For example, examples of the above aspects include quantum application types such as Quantum Key Distribution, Distributed Quantum Computing, Blind Quantum Computing, Quantum Sensor Network, and Quantum metrology.

[0229] Furthermore, for example, examples of the above viewpoints include those related to minimum fidelity, such as high (e.g., requiring a high level of QEC (Quantum Error Correlation)), medium (e.g., requiring purification), and low (e.g., physical Bell pairs).

[0230] Furthermore, for example, an example of the above viewpoint is a generation rate such as the required number of bell pairs per second. Also, for example, an example of the above viewpoint is a service level such as the relative merits of billing plans. Note that the viewpoints are not limited to the above examples, and any viewpoint can be adopted. For example, a weighting policy may be installed in advance in a component such as the NMG 50.

[0231] The seventh task is discussed in the following related literature: Cicconetti, Claudio, Marco Conti, and Andrea Passarella. "Quality of Service in Quantum Networks." IEEE Network 36.5 (2022): 24-31. Vardoyan, Gayane, and Stephanie Wehner. "Quantum Network Utility Maximization." arXiv preprint arXiv:2210.08135 (2022).

[0232] As described above, by performing quality of service (QoS) and resource reservation in the seventh task, the gateway device 100 can improve and maximize the quality of service, thereby enabling the appropriate operation of the quantum network.

[0233] [3-8. Eighth Task (Internal Fault Response)] [3-8-1. Overview of the Eighth Task] Next, an overview of the eighth task will be explained. Note that explanations of the same points as those explained above, such as the contents explained in other tasks, will be omitted as appropriate. The eighth task is a task related to internal fault response, such as fault detection and response. Key points of the eighth task include making sure that when a device has a fault, the surrounding devices of that device appropriately detect it.

[0234] The eighth task may assume the following: For example, the target is a device failure within an intranet. Also, for example, the network manager in charge of the network will perform the failure recovery, and network redundancy will also be included.

[0235] 17 to 19, a processing example related to the eighth task will be described. FIGS. 17 to 19 are sequence diagrams showing an example of processing related to the eighth task. The information processing system 1 executes the following processing related to the eighth task.

[0236] [3-8-2-1. Abnormal Stop of QPD] First, an example of abnormal stop of QPD will be described with reference to Fig. 17. Fig. 17 shows an example of specific processing when an abnormal stop of QPD occurs.

[0237] 17, the QPD 20 and the QRR 10a are adjacent to each other in the information processing system 1 (step S1501). For example, the QRR 10a in FIG. 17 is an adjacent node to the QPD 20 in FIG. 17. Note that step S1501 is intended to indicate that the QRR 10a in FIG. 17 is an adjacent node to the QPD 20 in FIG. 17 before the processing of step S1502 and subsequent steps, and does not indicate the processing.

[0238] The QPD 20 abnormally stops (step S1502). For example, the QPD 20 in FIG. 17 adjacent to the QRR 10a in FIG. 17 abnormally stops.

[0239] Then, the QGW 100 requests a health check from the QPD 20 (step S1503). For example, the QGW 100 requests a health check from the QPD 20 by transmitting a health check message requesting a health check to the QPD 20.

[0240] 17 illustrates a case in which the QPD 20 abnormally stops before step S1503, and therefore no response is returned from the QPD 20 to the QGW 100. The QGW 100 detects a timeout (step S1504). For example, the QGW 100 detects a timeout when a period of time has elapsed until a health check response is received. The QGW 100 updates the routing table (step S1505). For example, the QGW 100 determines that an abnormality has occurred in the QPD 20, and updates the routing table for the QPD 20.

[0241] The QGW 100 deletes the route to the QRR 10a adjacent to the QPD 20 (step S1506). For example, the QGW 100 deletes the route to the QRR 10a adjacent to the QPD 20 in which it has been determined that an abnormality has occurred, thereby excluding the route to the QPD 20 from routing candidates.

[0242] Furthermore, the QGW 100 notifies the NMG 50 of the error (step S1507). For example, the QGW 100 notifies the NMG 50 of the error regarding the QPD 20 by transmitting to the NMG 50 information indicating that the QPD 20 may have abnormally stopped.

[0243] Upon receiving the error notification, the NMG 50 restores the QPD 20 (step S1508). For example, a human administrator or the like using the NMG 50 that has received the error notification corrects the error in the QPD 20, thereby restoring the QPD 20. For example, the administrator (operator) or the like performs troubleshooting, including any work appropriate to the nature of the error, such as device replacement or software modification, to restore the QPD 20. In FIG. 17 , the QPD 20 is restored in step S1508.

[0244] Then, the restored QPD 20 requests a topology update (step S1509). For example, the restored QPD 20 requests the QGW 100 to update the route deleted in step S1506 to the restored topology. For example, the QPD 20 requests the QGW 100 to update the topology in the same way as in the processing in the second task.

[0245] The QGW 100 adds a route (step S1510). For example, upon receiving a request from the recovered QPD 20, the QGW 100 adds a route to the QRR 10a adjacent to the recovered QPD 20. For example, the QGW 100 adds a route to the QRR 10a adjacent to the recovered QPD 20, that is, restores the route deleted in step S1506, thereby adding the route to the QPD 20 to the routing candidates.

[0246] [3-8-2-2. Abnormal Stop of QRR] Next, an example of abnormal stop of QRR will be described with reference to Fig. 18. Fig. 18 shows an example of specific processing when an abnormal stop of QRR occurs.

[0247] It should be noted that QRR 10a-2 shown as "QRR#2" and QRR 10a-3 shown as "QRR#3" in Fig. 18 are adjacent nodes of QRR 10a-1 shown as "QRR#1" in Fig. 18. In this way, Fig. 18 will explain an example in which there are multiple adjacent nodes, QRR 10a-2 and QRR 10a-3, for QRR 10a-1.

[0248] As described above, in FIG. 18, in the information processing system 1, QRR 10a-2 and QRR 10a-1 are adjacent to each other, and the route between QRR 10a-2 and QRR 10a-1 is set as the preferred route (step S1601). Also, QRR 10a-3 and QRR 10a-1 are adjacent to each other (step S1602). For example, in FIG. 18, the route between QRR 10a-2 and QRR 10a-1 is set to be used preferentially over the route between QRR 10a-3 and QRR 10a-1. Note that steps S1601 and S1602 are intended to indicate that QRR 10a-2 and QRR 10a-3 are adjacent nodes of QRR 10a-1 before the processing of step S1603 and subsequent steps, and do not indicate the processing.

[0249] The QRR 10a-2 comes to an abnormal stop (step S1603). For example, the QRR 10a-2 in FIG. 18, which is adjacent to the QRR 10a-1 in FIG. 18, comes to an abnormal stop.

[0250] Then, the QGW 100 requests the QRR 10a-2 to perform a health check (step S1604). For example, the QGW 100 requests the QRR 10a-2 to perform a health check by transmitting a health check message to the QRR 10a-2.

[0251] 18 shows a case where the QRR 10a-2 has abnormally stopped at a point before step S1604, and therefore no response is returned from the QRR 10a-2 to the QGW 100. The QGW 100 detects a timeout (step S1605). For example, the QGW 100 detects a timeout when the period until a health check response is received has elapsed. The QGW 100 updates the routing table (step S1606). For example, the QGW 100 determines that an abnormality has occurred in the QRR 10a-2, and updates the routing table for the QRR 10a-2.

[0252] The QGW 100 deletes the route to the QRR 10a-1 adjacent to the QRR 10a-2 (step S1607). For example, the QGW 100 instructs the QRR 10a-1 to delete the route to the QRR 10a-1 adjacent to the QRR 10a-2 in which it has been determined that an abnormality has occurred, thereby excluding the route to the QRR 10a-2 from routing candidates.

[0253] Furthermore, the QGW 100 sets a priority route for the QRR 10a-3, which is an adjacent node of the QRR 10a-1 and has no abnormalities (step S1608). For example, the QGW 100 sets a priority route for the route between the QRR 10a-3, which is an adjacent node of the QRR 10a-1 and has no abnormalities, and the QRR 10a-1.

[0254] Furthermore, the QGW 100 notifies the NMG 50 of the error (step S1609). For example, the QGW 100 notifies the NMG 50 of the error regarding the QRR 10a-2 by transmitting to the NMG 50 information indicating that the QRR 10a-2 may have abnormally stopped.

[0255] The NMG 50, which has received the error notification, restores the QRR 10a-2 (step S1610). For example, a human administrator or the like who uses the NMG 50, who has received the error notification, restores the QRR 10a-2 by correcting the error in the QRR 10a-2. In FIG. 18, the QRR 10a-2 is restored in step S1610.

[0256] Then, the restored QRR 10a-2 requests a topology update (step S1611). For example, the restored QRR 10a-2 requests the QGW 100 to update the route deleted in step S1607 to the restored topology. For example, the QRR 10a-2 requests the QGW 100 to update the topology in the same way as in the processing in the first task.

[0257] For example, the QGW 100 that has received a request from the recovered QRR 10a-2 adds a route to the QRR 10a-1 adjacent to the recovered QRR 10a-2. For example, the QGW 100 adds a route to the QRR 10a-1 adjacent to the recovered QRR 10a-2, that is, restores the route deleted in step S1607, thereby adding the route to the QRR 10a-2 to the routing candidates.

[0258] [3-8-2-3. Link Cost Abnormality] Next, an example of a link cost abnormality will be described with reference to Fig. 19. Fig. 19 shows an example of a specific process when a link cost abnormality occurs.

[0259] It is assumed that the QRR 10a-2 shown as "QRR#2" in Fig. 19 is an adjacent node of the QRR 10a-1 shown as "QRR#1" in Fig. 19. In this way, Fig. 19 will be described as an example in which the QRR 10a-1 and the QRR 10a-2 are (mutually) adjacent nodes.

[0260] 19, a decrease in the physical Bell pair generation rate occurs in the QRR 10a-1 and the QRR 10a-2 in the information processing system 1 (step S1701). For example, a decrease occurs in the physical Bell pair generation rate in the quantum entanglement between the QRR 10a-1 and the QRR 10a-2.

[0261] Then, the QGW 100 requests the QRR 10a-2 to perform a health check (step S1702). For example, the QGW 100 requests the QRR 10a-2 to perform a health check by transmitting a health check message to the QRR 10a-2.

[0262] 19, since a decrease in the physical bell pair generation rate between QRR 10a-1 and QRR 10a-2 has occurred even at the time of step S1702, a response indicating a lower physical bell pair generation rate is sent from QRR 10a-2 to QGW 100 (step S1703). As a result, QGW 100 receives a response indicating a lower physical bell pair generation rate from QRR 10a-2 to QGW 100.

[0263] The QGW 100 compares the generation rate with a threshold to determine whether an anomaly has occurred in the generation of the quantum state (step S1704). For example, the QGW 100 compares the physical Bell pair generation rate indicated in the response received from the QRR 10a-2 with a threshold for quantum state generation anomalies, and determines that an anomaly has occurred in the generation of the quantum state because the physical Bell pair generation rate is lower than the threshold. Therefore, the QGW 100 updates the routing table (step S1705). For example, the QGW 100 determines that an anomaly has occurred in the generation of the quantum state between the QRR 10a-2 and the QRR 10a-1, and updates the routing table for the QRR 10a-2.

[0264] The QGW 100 deletes the route to the QRR 10a-1 adjacent to the QRR 10a-2 (step S1706). For example, the QGW 100 instructs the QRR 10a-2 to delete the route between the QRR 10a-2 and the QRR 10a-1, where it has been determined that an anomaly has occurred in the generation of the quantum state, thereby excluding the route to the QRR 10a-1 from routing candidates.

[0265] Furthermore, the QGW 100 notifies the NMG 50 of the generation anomaly (step S1707). For example, the QGW 100 notifies the NMG 50 of the generation anomaly of the quantum state between QRR 10a-2 and QRR 10a-1 by transmitting information indicating that an anomaly may have occurred in the generation of the quantum state between QRR 10a-2 and QRR 10a-1.

[0266] Upon receiving the notification of the generation anomaly, the NMG 50 performs hardware calibration of the QRR 10a-1 and the QRR 10a-2 (steps S1708 and S1709). For example, a human administrator or the like who uses the NMG 50 who receives the notification of the generation anomaly performs hardware calibration on the QRR 10a-1 and the QRR 10a-2, thereby resolving the generation anomaly of the quantum state between the QRR 10a-2 and the QRR 10a-1. In FIG. 19, steps S1708 and S1709 resolve the generation anomaly of the quantum state between the QRR 10a-2 and the QRR 10a-1.

[0267] Then, the QRR 10a-2 and QRR 10a-1, whose quantum state generation anomaly has been resolved, execute a link benchmark job (step S1710). Then, the QRR 10a-2, whose quantum state generation anomaly between it and the QRR 10a-1 has been resolved, requests a topology update (step S1711). For example, the restored QRR 10a-2 requests the QGW 100 to update the route deleted in step S1706 to the restored topology. For example, the QRR 10a-2 requests a topology update from the QGW 100, similar to the processing in the first task.

[0268] For example, the QGW 100, upon receiving a request from the restored QRR 10a-2, adds a route between the QRR 10a-2 and the QRR 10a-1, for which the quantum state generation anomaly has been resolved. For example, the QGW 100 adds a route between the QRR 10a-2 and the QRR 10a-1, for which the quantum state generation anomaly has been resolved, that is, restores the route deleted in step S1706, thereby adding the route to the QRR 10a-1 to the routing candidates.

[0269] In this way, when responding to an internal failure, the information processing system 1 performs various processes depending on the nature of the detected failure. For example, in the information processing system 1, if a relay, link, or calculation QPU in the network stops abnormally due to a failure or other reason, the QGW 100 removes routes that pass through the affected relay or QPU from available routes and notifies the network manager of the equipment failure. The network manager then performs recovery, and once recovery is complete, the equipment notifies the QGW 100 or adjacent nodes that it is available again. The QGW 100 then makes the recovered route available again.

[0270] Furthermore, for example, in the information processing system 1, if the link creation rate or the fidelity of the created state indicates an abnormal value, the route including the relay that includes the target link is removed from the routing table and a performance measurement request is made. For example, in the information processing system 1, if the link performance value improves, the path that passes through the target relay is added back to the routing table.

[0271] Furthermore, for example, in the information processing system 1, if the link performance value does not improve, the information processing system 1 performs a physical system initialization process for the target repeater, etc., and measures the performance again. Furthermore, for example, if the link performance does not improve, the information processing system 1 notifies the network manager that the device has failed. For example, if the link performance improves, the information processing system 1 performs a process such as adding a path that passes through the target repeater, etc., to the routing table again, and takes measures such as returning to the state before the failure was detected.

[0272] Furthermore, for example, in the information processing system 1, if a quantum gateway router abnormally terminates due to a failure and a backup quantum gateway router (backup router) is set, the QGW 100 will switch to the backup router when it detects a failure in one of the devices. The QGW 100 will notify the network manager that it has detected a gateway failure, and the network manager will carry out recovery work.

[0273] Furthermore, for example, in the information processing system 1, if a backup router is not set, the QGW 100 notifies the network manager of the equipment failure, and the network manager performs recovery work.

[0274] The eighth task is discussed in the following related literature: Pirker, Alexander, and Wolfgang Dur. "A quantum network stack and protocols for reliable entanglement-based networks." New Journal of Physics 21.3 (2019): 033003.

[0275] As described above, by detecting and responding to a failure in the eighth task, the gateway device 100 can respond appropriately to the failure, thereby enabling rapid recovery, partial maintenance of services, and guarantee of service reliability. Therefore, the gateway device 100 can enable appropriate operation of the quantum network. For example, the gateway device 100 requests information including a physical Bell pair generation rate from at least one of two or more quantum nodes that generate physical Bell pairs in a quantum intranet, receives the physical Bell pair generation rate from the quantum node in the quantum intranet, and if the physical Bell pair generation rate is not a normal value, updates the routing table and notifies the network manager of the physical Bell pair generation abnormality so that the error can be corrected for at least one of the two or more quantum nodes that generate physical Bell pairs.

[0276] [3-9. Ninth Task (Logging)] [3-9-1. Overview of the Ninth Task] Next, an overview of the ninth task will be explained. Note that explanations of the same points as those explained above, such as the contents explained in other tasks, will be omitted as appropriate. The ninth task is a task related to logging. Key points in the ninth task include selecting items to be recorded in the log according to the intended purpose.

[0277] The ninth task may also be premised on the following points: For example, the type and number of logs to be acquired and displayed may be determined based on the size of the network, the settings of the network manager, and the like.

[0278] [3-9-2. Processing Example Related to Ninth Task] A processing example related to the ninth task will now be described. The information processing system 1 executes the following processing related to the ninth task. When performing logging, in the information processing system 1, the QGW 100 collects information related to each component.

[0279] For example, in the information processing system 1, when a log relating to the status of a repeater or QPU in the network is output, the contents of the request and response at the time of a health check periodically performed by the QGW 100 are displayed and recorded on the console as a log at any time together with timestamps, etc. For example, when the QGW 100 outputs a log relating to the status of the QPD 20, the QRR 10a, etc., the contents of the request and response at the time of a health check periodically performed on the QPD 20, the QRR 10a, etc. are displayed and recorded on the console as a log at any time together with timestamps, etc.

[0280] If the response during a health check times out or if a device failure or a status generation abnormality is detected, the QGW 100 outputs that fact to a log and, in some cases, notifies the network manager as an alert. For example, if the response during a health check of the QPD 20, the QRR 10a, or the like times out or if a device failure or a status generation abnormality is detected, the QGW 100 outputs that fact to a log and, in some cases, notifies the NMG 50 as an alert.

[0281] As described above, by performing logging in the ninth task, the gateway device 100 can store information and improve service quality and reliability in the future. Therefore, the gateway device 100 can enable proper operation of the quantum network.

[0282] [4. Others] The processing according to each of the above-described embodiments may be implemented in various different forms (modifications) other than the above-described embodiments and modifications.

[0283] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using known methods. Furthermore, the information, including the processing procedures, specific names, various data, and parameters shown in the above documents and drawings, can be changed as desired unless otherwise specified. For example, the various information shown in each drawing is not limited to the information shown in the drawings.

[0284] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0285] Furthermore, the above-described embodiments and modifications can be combined as appropriate within the scope of not causing any contradiction in the processing content.

[0286] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0287] 5. Effects of the Present Disclosure As described above, a gateway device (gateway device 100 in an embodiment) according to the present disclosure is a gateway device for connecting a quantum internet and a quantum intranet, and receives information indicating the communication quality between a quantum node and other quantum nodes calculated by a quantum node in the quantum intranet, constructs a routing table for the quantum intranet, receives requests from nodes in the quantum internet, references the routing table for the quantum intranet, and transmits the requests to quantum nodes in the quantum intranet based on the referenced routing table.

[0288] As a result, the gateway device according to the present disclosure constructs a routing table for the quantum intranet, and when a request is received from a node in the quantum internet, it can refer to the routing table for the quantum intranet and transmit the request to an appropriate quantum node in the quantum intranet based on the referenced routing table. Thus, the gateway device can enable appropriate operation of the quantum network.

[0289] In addition, the gateway device is a gateway device for connecting the quantum internet and the quantum intranet, and at the stage of starting communication of quantum information, generates quantum entanglement with a quantum node in the quantum internet, measures the quality of the quantum entanglement, and if the measured quality is normal, continues communication, and if the measured quality is not normal, blocks communication.

[0290] As a result, the gateway device according to the present disclosure generates quantum entanglement with quantum nodes in the quantum internet at the stage of starting communication of quantum information, measures the quality of the quantum entanglement, and continues communication if the measured quality is normal, but cuts off communication if the measured quality is abnormal, thereby making it possible to appropriately establish trust in the quantum communication path. Therefore, the gateway device can enable appropriate operation of the quantum network.

[0291] The gateway device is a gateway device for connecting the quantum internet and the quantum intranet, which sends a message to an adjacent quantum node, receives a response from the adjacent quantum node, requests the adjacent node to obtain information representing the communication quality between the gateway device and the adjacent quantum node, and obtains the information representing the communication quality between the adjacent quantum nodes from the gateway device.

[0292] As a result, the gateway device according to the present disclosure can request adjacent quantum nodes to provide information indicating the communication quality between the gateway device and the adjacent quantum nodes, and by obtaining the information indicating the communication quality between the adjacent quantum nodes from the gateway device, it becomes possible to appropriately determine whether or not to participate in the quantum internet. Therefore, the gateway device can enable appropriate operation of the quantum network.

[0293] The gateway device is a gateway device for connecting the quantum internet and the quantum intranet, and receives a routing table update message sent in response to an update of the routing table of an adjacent quantum node, and updates the routing table based on the routing table update message of the adjacent quantum node.

[0294] This allows the gateway device according to the present disclosure to update its routing table based on the routing table update messages of neighboring quantum nodes, thereby enabling appropriate routing selection in the quantum internet, thereby enabling appropriate operation of the quantum network.

[0295] The gateway device is a gateway device for connecting the quantum internet and the quantum intranet, and receives notifications of quantum state generation anomalies from adjacent quantum nodes and notifies the network manager of the errors for error correction on quantum repeaters located between the adjacent quantum nodes and the gateway device.

[0296] As a result, when the gateway device according to the present disclosure receives a notification of a quantum state generation anomaly from an adjacent quantum node, it can notify the network manager of the error to perform error correction on the quantum repeater between the adjacent quantum node and the gateway device, thereby enabling the gateway device to properly operate the quantum network.

[0297] In addition, the gateway device is a gateway device for connecting the quantum internet and the quantum intranet, and requests information including a physical Bell pair generation rate from at least one of two or more quantum nodes that generate physical Bell pairs in the quantum intranet, receives the physical Bell pair generation rate from the quantum node in the quantum intranet, and if the physical Bell pair generation rate is not a normal value, updates the routing table and notifies a network manager of the physical Bell pair generation abnormality for error correction for at least one of the two or more quantum nodes that generate physical Bell pairs.

[0298] This allows the gateway device according to the present disclosure to receive the physical Bell pair generation rate from the quantum node in the quantum intranet, and if the physical Bell pair generation rate is not normal, update the routing table and notify the network manager of the physical Bell pair generation abnormality to correct the error for at least one of the two or more quantum nodes that generate the physical Bell pairs, thereby enabling appropriate fault notification. Therefore, the gateway device can enable proper operation of the quantum network.

[0299] [6. Hardware Configuration Example] The gateway device 100, relay node 10, QPD 20, etc. described above are realized by a configuration that appropriately combines classical computers, quantum computers, etc., configured as shown below, for example. An example of the hardware configuration of the gateway device 100 will be described below. Note that the hardware configuration shown below is merely an example, and any hardware configuration can be adopted for the gateway device 100, relay node 10, QPD 20, etc., as long as the desired processing is possible.

[0300] For example, the classical function unit 110 of the gateway device 100 is realized by a classical computer having the following configuration. The classical computer has a CPU, RAM, ROM (Read Only Memory), HDD (Hard Disk Drive), a classical communication interface, and an input / output interface. Each unit of the classical computer is connected by a bus.

[0301] The CPU operates based on programs stored in the ROM or HDD and controls each part. For example, the CPU loads the programs stored in the ROM or HDD into the RAM and executes processes corresponding to the various programs.

[0302] The ROM stores boot programs such as the Basic Input Output System (BIOS) that is executed by the CPU when the classical computer is started, as well as programs that depend on the hardware of the classical computer.

[0303] The HDD is a computer-readable recording medium that non-temporarily records programs executed by the CPU, data used by such programs, etc. Specifically, the HDD is a recording medium that records the information processing program according to the present disclosure, which is an example of program data.

[0304] A classical communication interface is an interface that allows a classical computer to connect to an external classical network (e.g., the classical Internet). For example, a CPU can receive data from other devices or send data generated by the CPU to other devices via the classical communication interface.

[0305] An input / output interface is an interface for connecting an input / output device to a classical computer. For example, a CPU receives data from an input device such as a keyboard or a mouse via the input / output interface. The CPU also transmits data to an output device such as a display, a speaker, or a printer via the input / output interface. The input / output interface may also function as a media interface for reading programs recorded on a predetermined recording medium. Examples of media include optical recording media such as a DVD (Digital Versatile Disc) or a PD (Phase Change Rewritable Disk), magneto-optical recording media such as an MO (Magneto-Optical Disk), tape media, magnetic recording media, or semiconductor memory.

[0306] For example, when a classical computer functions as the gateway device 100 according to the embodiment, the CPU of the classical computer executes an information processing program loaded onto the RAM to realize functions of the control unit 130, etc. The information processing program according to the present disclosure and data in the storage unit 120 are stored in the HDD. The CPU reads and executes the program data from the HDD, but as another example, the CPU may obtain these programs from other devices via an external classical network.

[0307] Furthermore, for example, the quantum function unit 150 of the gateway device 100 is realized by a quantum computer having the following configuration. The quantum computer has a QPU, a quantum communication interface, etc. Each unit of the quantum computer is connected by an arbitrary configuration such as a transmission line.

[0308] The QPU performs quantum computation functions and quantum memory functions. The QPU operates according to predetermined controls and performs processes such as quantum computation and quantum state storage. The quantum communication interface is an interface for connecting the quantum computer to an external quantum network (e.g., the quantum internet). For example, the QPU receives data from other devices and transmits data generated by the QPU to other devices via the quantum communication interface.

[0309] Note that the present technology can also be configured as follows: (1) A gateway device for connecting a quantum internet and a quantum intranet, comprising: receiving information representing communication quality between a quantum node and other quantum nodes calculated by the quantum node in the quantum intranet; constructing a routing table for the quantum intranet; receiving a request from a node in the quantum internet; referencing the routing table for the quantum intranet; and transmitting the request to a quantum node in the quantum intranet based on the referenced routing table. (2) A gateway device for connecting a quantum internet and a quantum intranet, comprising: at a stage of starting communication of quantum information, generating quantum entanglement with a quantum node in the quantum internet, measuring the quality of the quantum entanglement, continuing communication if the measured quality is normal, and cutting off communication if the measured quality is not normal. (3) A gateway device for connecting a quantum internet and a quantum intranet, the gateway device comprising: (a) a gateway device configured to transmit a message to an adjacent quantum node; (b) a gateway device configured to receive a response from the adjacent quantum node; (c) a gateway device configured to request the adjacent quantum node to obtain information indicating the communication quality between the adjacent quantum node and the gateway device from the adjacent quantum node; and (d) a gateway device configured to receive a routing table update message transmitted in response to an update of a routing table of an adjacent quantum node; and (d) a gateway device configured to update the routing table based on the routing table update message of the adjacent quantum node.(5) A gateway device for connecting a quantum internet and a quantum intranet, the gateway device receiving a notification of a quantum state generation anomaly from an adjacent quantum node, and notifying a network manager of the error for error correction for a quantum repeater between the adjacent quantum node and the gateway device. (6) A gateway device for connecting a quantum internet and a quantum intranet, the gateway device requesting information including a physical Bell pair generation rate from at least one of two or more quantum nodes that generate physical Bell pairs in the quantum intranet, receiving the physical Bell pair generation rate from a quantum node in the quantum intranet, and if the physical Bell pair generation rate is not a normal value, updating a routing table, and notifying a network manager of the physical Bell pair generation anomaly for error correction for at least one of the two or more quantum nodes that generate the physical Bell pairs.

[0310] REFERENCE SIGNS LIST 1 Information processing system (quantum-classical hybrid system) 2 Quantum data center 10 Relay node 10a QRR 10b EQRR 10c IQR 20 QPD 30 CLT 100 Gateway device (QGW) 110 Classical function unit (classical computer unit) 120 Memory unit 130 Control unit 140 Communication unit 150 Quantum function unit (quantum computer unit) 160 Quantum memory unit 170 Quantum control unit 180 Quantum communication unit CN Classical network CN1 Classical intranet CN2 Classical internet QN Quantum network QN1 Quantum intranet QN2 Quantum internet

Claims

1. A gateway device for connecting a quantum internet and a quantum intranet, comprising: receiving information representing communication quality between a quantum node and other quantum nodes calculated by the quantum node in the quantum intranet; constructing a routing table for the quantum intranet; receiving a request from a node in the quantum internet; referring to the routing table for the quantum intranet; and transmitting the request to a quantum node in the quantum intranet based on the referred routing table.

2. A gateway device for connecting a quantum internet and a quantum intranet, which generates quantum entanglement with a quantum node in the quantum internet at a stage of starting communication of quantum information, measures the quality of the quantum entanglement, continues communication if the measured quality is normal, and cuts off communication if the measured quality is not normal.

3. A gateway device for connecting a quantum internet and a quantum intranet, comprising: transmitting a message to an adjacent quantum node; receiving a response from the adjacent quantum node; requesting the adjacent node to obtain information indicating communication quality between the gateway device from the adjacent quantum node; and obtaining the information indicating communication quality between the adjacent quantum node from the gateway device.

4. A gateway device for connecting a quantum internet and a quantum intranet, the gateway device receiving a routing table update message transmitted in response to an update of the routing table of an adjacent quantum node, and updating the routing table based on the routing table update message of the adjacent quantum node.

5. A gateway device for connecting a quantum internet and a quantum intranet, the gateway device receiving a notification of a quantum state generation anomaly from an adjacent quantum node, and notifying a network manager of the error for error correction for a quantum repeater between the adjacent quantum node and the gateway device.

6. A gateway device for connecting a quantum internet and a quantum intranet, comprising: a gateway device that requests information including a physical Bell pair generation rate from at least one of two or more quantum nodes that generate physical Bell pairs in the quantum intranet; receives the physical Bell pair generation rate from a quantum node in the quantum intranet; if the physical Bell pair generation rate is not a normal value, updates a routing table; and notifies a network manager of a physical Bell pair generation abnormality for error correction for at least one of the two or more quantum nodes that generate the physical Bell pairs.

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