Method for time synchronization between source and sink nodes in entanglement distribution network and related equipment

Abstract

The application provides a time synchronization method between source and sink nodes in an entanglement distribution network and related equipment. The entanglement distribution network comprises a plurality of control centers, time reference nodes and quantum source and sink nodes to be synchronized connected with the control centers. The method comprises the following steps: determining a clock source of the entanglement distribution network; performing initial synchronization on a basic clock of any source and sink node through a time synchronization protocol according to the clock source; determining a source and sink node to be synchronized, receiving a synchronization request of the source and sink node to be synchronized, determining a type of the synchronization request, and performing time synchronization according to the type of the synchronization request. Based on different synchronization requirements of nodes, different entanglement distribution or entanglement exchange methods are adopted through a control center judgment mode, time synchronization between nodes is realized, and then full-network synchronization of the source and sink entanglement network is realized. The method has the advantages of long synchronization distance, high synchronization precision and high security.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum information and optical communication technology, and in particular to a time synchronization method between source and sink nodes in an entanglement distribution network and related equipment. BACKGROUND

[0002] With the rapid development of the communication industry, wireless communication has developed to 5G, and the precision requirement of time synchronization has reached tens of nanoseconds. Future 6G and optical communication will enter Tbits, and there will be higher time synchronization requirements. The classical synchronization technical solution is limited by the standard quantum limit, and it is difficult to greatly improve the precision. Therefore, quantum synchronization technology is proposed. Quantum synchronization technology is a new technology that combines quantum technology and synchronization technology to obtain frequency and time synchronization information through preparation, regulation and detection of quantum states.

[0003] However, most of the current time synchronization schemes based on quantum entanglement technology have strict requirements for the transmission network, such as inserting a variable time delay that increases or decreases with time or requiring the time delay or refractive index of the transmission link to be dynamically adjustable, but it is difficult to achieve in an actual network. Therefore, the implementation of quantum synchronization technology has brought many adverse effects. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a time synchronization method between source and sink nodes in an entanglement distribution network and related equipment.

[0005] To achieve the above purpose, the present application provides a time synchronization method between source and sink nodes in an entanglement distribution network, the source and sink nodes including a source node and a sink node, the source node being a network node that sends original data packets, the sink node being a network node that receives data packets, the entanglement distribution network including a plurality of control centers, time reference nodes and nodes to be synchronized connected to the control centers, the time reference nodes being the source nodes, and the nodes to be synchronized being the sink nodes; the method comprising:

[0006] determining the clock source of the entanglement distribution network;

[0007] initially synchronizing the base clock of any of the nodes to be synchronized according to the clock source through a time synchronization protocol;

[0008] determining the nodes to be synchronized, receiving a synchronization request of the nodes to be synchronized, determining the type of the synchronization request, and performing time synchronization according to the type of the synchronization request.

[0009] Optionally, before synchronizing the base clock of any of the nodes to be synchronized according to the clock source through a time synchronization protocol, the method further comprises:

[0010] A network topology graph of the plurality of to-be-synchronized nodes is established based on a preset entanglement distribution distance.

[0011] Optionally, the method comprises:

[0012] In response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and any of the control centers, calculating a time difference between the to-be-synchronized node and the control center, and performing time synchronization according to the time difference and the network topology graph;

[0013] In response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and a time reference node belonging to the same control center, calculating a time difference between the to-be-synchronized node and the time reference node, and performing time synchronization according to the time difference and the network topology graph;

[0014] In response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and a time reference node across control centers, calculating a time difference between the to-be-synchronized node and the time reference node, and correcting a clock of the to-be-synchronized node according to the time difference and the network topology graph, so that the to-be-synchronized node and the time reference node achieve time synchronization.

[0015] Optionally, in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and any of the control centers, calculating a time difference between the to-be-synchronized node and the control center, and performing time synchronization according to the time difference and the network topology graph, comprises:

[0016] In response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and any of the control centers, determining a first synchronization topology graph according to the network topology graph;

[0017] Determining a first entangled state particle and a second entangled state particle through an EPR source, and distributing the first entangled state particle and the second entangled state particle to the to-be-synchronized node and the control center respectively according to the first synchronization topology graph; wherein the first entangled state particle and the second entangled state particle are entangled with each other;

[0018] Establishing a communication channel between the to-be-synchronized node and the control center according to the first entangled state particle and the second entangled state particle;

[0019] The to-be-synchronized node receives a time synchronization message through the communication channel and acquires a current timestamp, and determines a probability distribution of a first superposition state of the first entangled state particle in the to-be-synchronized node according to the current timestamp;

[0020] Determining a time difference between the to-be-synchronized node and the control center according to the probability distribution of the first superposition state of the first entangled state particle.

[0021] correcting a clock of the to-be-synchronized node according to the time difference, to realize time synchronization of the to-be-synchronized node and the control center.

[0022] Optionally, in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and a time reference node belonging to the same control center, the time difference between the to-be-synchronized node and the time reference node is calculated, and time synchronization is performed according to the time difference and the network topology map, including:

[0023] In response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and the time reference node, a second synchronization topology map is determined according to the network topology map.

[0024] The first entangled pair and the second entangled pair are determined by an EPR source; according to the second synchronization topology map, the third entangled state particle is distributed to the time reference node, the fourth entangled state particle and the fifth entangled state particle are distributed to the control center, and the sixth entangled state particle is distributed to the to-be-synchronized node, and in response to determining that the distribution is successful, a communication channel of the to-be-synchronized node, the time reference node and the control center is established; wherein the first entangled pair includes a third entangled state particle and a fourth entangled state particle, the second entangled pair includes a fifth entangled state particle and a sixth entangled state particle.

[0025] The to-be-synchronized node receives a time synchronization message through the communication channel and acquires a current timestamp, and determines a probability distribution of a second superposition state of the sixth entangled state particle in the to-be-synchronized node according to the current timestamp.

[0026] According to the probability distribution of the sixth entangled state particle, a time difference between the to-be-synchronized node and the time reference node is determined.

[0027] According to the time difference, a clock of the to-be-synchronized node is corrected, to realize time synchronization of the to-be-synchronized node and the time reference node.

[0028] Optionally, in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and the time reference node across control centers, a time difference between the to-be-synchronized node and the time reference node is calculated, and a clock of the to-be-synchronized node is corrected according to the time difference and the network topology map, to realize time synchronization between the to-be-synchronized node and the time reference node, including:

[0029] The number of control centers is determined, and in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and the time reference node, a third synchronization topology map is determined according to the network topology map.

[0030] determining a plurality of EPR sources according to the number of the control centers in the third synchronization topology graph; determining a plurality of entangled state particles through the EPR sources, and distributing the plurality of entangled state particles to the to-be-synchronized nodes, the time reference node, and the plurality of control centers respectively; wherein the to-be-synchronized nodes and the time reference node distribute one entangled state particle respectively, and any control center distributes two entangled state particles;

[0031] establishing a communication channel of the to-be-synchronized nodes, the time reference node, and the control centers according to the plurality of entangled state particles, the to-be-synchronized nodes, the time reference node, and the control centers;

[0032] receiving a time synchronization message through the communication channel, and obtaining a current timestamp, and determining a probability distribution of a third superposition state of the entangled state particle corresponding to the to-be-synchronized node according to the current timestamp;

[0033] determining a time difference between the to-be-synchronized node and the control center according to the probability distribution of the entangled state particle;

[0034] modifying a clock of the to-be-synchronized node according to the time difference, so as to realize time synchronization between the to-be-synchronized node and the time reference node.

[0035] Optionally, the method comprises:

[0036] The time synchronization protocol is a PTP protocol or an NTP protocol.

[0037] Based on the same inventive concept, the example embodiments of the present application further provide a source-destination node time synchronization device in an entanglement distribution network, characterized in that the source-destination node comprises a source node and a destination node, the source node is a network node for sending original data packets, the destination node is a network node for receiving data packets, the entanglement distribution network comprises a plurality of control centers, a time reference node, and to-be-synchronized quantum source-destination nodes connected with the control centers, the time reference node is the source node, and the to-be-synchronized node is the destination node, and the device comprises:

[0038] a determining module configured to determine a clock source of the entanglement distribution network;

[0039] a first synchronization module configured to initially synchronize a basic clock of any to-be-synchronized node through a time synchronization protocol according to the clock source;

[0040] A second synchronization module is configured to determine the node to be synchronized, receive a synchronization request of the node to be synchronized, determine a type of the synchronization request, and perform time synchronization according to the type of the synchronization request.

[0041] Based on the same inventive concept, the example embodiments of the present application further provide an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor implements the time synchronization method between source and sink nodes in the entanglement distribution network according to any one of the above embodiments when executing the computer program.

[0042] Based on the same inventive concept, the example embodiments of the present application further provide a non-transitory computer readable storage medium, which stores computer instructions for causing a computer to execute the time synchronization method between source and sink nodes in the entanglement distribution network according to any one of the above embodiments.

[0043] As can be seen from the above, the present application provides a time synchronization method between source and sink nodes in an entanglement distribution network and related equipment, wherein the entanglement distribution network comprises a plurality of control centers, time reference nodes connected to the control centers, and nodes to be synchronized; specifically, the method comprises: determining the synchronization service type of the node to be synchronized with synchronization demand through the control center, and using the corresponding entanglement distribution or entanglement exchange method to complete the end-to-end time synchronization service between users in the entanglement distribution network. Based on different synchronization requirements of nodes, the present application uses different entanglement distribution or entanglement exchange methods through the judgment of the control center, realizes the time synchronization between nodes, and further realizes the network synchronization of the quantum entanglement network, and has the advantages of long synchronization distance, high synchronization precision, and high security. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the present application or related art, the following will briefly introduce the drawings needed to be used in the embodiments or related art descriptions. Obviously, the drawings in the following description are only examples of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0045] Figure 1 The flowchart of the time synchronization method between source and sink nodes in the entanglement distribution network of the embodiments of the present application;

[0046] Figure 2 The topology diagram of the entanglement distribution network of the embodiments of the present application;

[0047] Figure 3A structural schematic diagram of a first synchronization topology of an embodiment of the present application;

[0048] Figure 4 An implementation flowchart of the first synchronization topology of an embodiment of the present application;

[0049] Figure 5 A structural schematic diagram of a second synchronization topology of an embodiment of the present application;

[0050] Figure 6 An implementation flowchart of the second synchronization topology of an embodiment of the present application;

[0051] Figure 7 A structural schematic diagram of a third synchronization topology of an embodiment of the present application;

[0052] Figure 8 An implementation flowchart of the third synchronization topology of an embodiment of the present application;

[0053] Figure 9 A structural schematic diagram of a time synchronization device between source and sink nodes in an entangled distribution network of an embodiment of the present application;

[0054] Figure 10 A structural schematic diagram of an electronic device of an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the common meanings understood by those with ordinary skills in the art to which the present application belongs. The terms "first", "second", and similar terms used in the embodiments of the present application do not represent any order, number, or importance, but are only used to distinguish different components. The terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms do not mean physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like only represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships can also change accordingly.

[0057] As described in the background section, most of the current time synchronization schemes based on quantum entanglement technology have strict requirements for the transmission network, such as inserting a variable time delay that increases or decreases over time in the network or requiring the time delay or refractive index of the transmission link to be dynamically adjustable, which is difficult to achieve in an actual network. Therefore, the implementation of quantum synchronization technology is adversely affected.

[0058] Therefore, the present application provides a time synchronization method between source and destination nodes in an entanglement distribution network, a device, an electronic device, and a storage medium. The entanglement distribution network includes a plurality of control centers and quantum nodes connected to the control centers. Specifically, the method includes determining the synchronization service type of the node with synchronization requirements through the control center, and using the corresponding entanglement distribution or entanglement swapping method to complete the end-to-end time synchronization service between users in the network. Quantum swapping is the teleportation of entangled states, which is a joint basis measurement of two entangled systems to achieve the entanglement of the other two local particles. The preparation process of the entangled state is the basis for the entangled state as a carrier for synchronization. In the spontaneous parametric down-conversion process, when the pump light is incident on the nonlinear crystal, each photon of the pump light radiation will be converted into two photons with entanglement characteristics with lower frequency during the scattering of the nonlinear crystal, one is a signal photon and the other is an idle photon. This pair of photons is called spontaneous parametric down-conversion two photons, and the time difference between them is less than picoseconds, so the two photons in the entangled pair can be considered to be generated at the same time, which provides a theoretical and experimental basis for high-precision positioning and clock synchronization measurement. Therefore, as long as the stability of the clock can be ensured, a pair of entangled states can be used for time service system. Since the quantum clock is based on the study of quantum entanglement characteristics, it can provide security protection for the system according to the Heisenberg uncertainty principle and the quantum no-cloning theorem.

[0059] The time synchronization method between source and destination nodes in an entanglement distribution network provided by the embodiments of the present application will be described in detail below through specific embodiments.

[0060] Figure 1 An exemplary flowchart of a time synchronization method between source and destination nodes in an entanglement distribution network provided by the embodiments of the present application is shown.

[0061] Reference Figure 1 The time synchronization method between source and destination nodes in an entanglement distribution network provided by the embodiments of the present application specifically includes the following steps:

[0062] Step 101, determining the clock source of the entanglement distribution network;

[0063] Step 102, according to the clock source, synchronizing the base clock of any of the to-be-synchronized nodes through a time synchronization protocol;

[0064] Step 103, determining the to-be-synchronized node, receiving the synchronization request of the to-be-synchronized node, determining the type of the synchronization request, and performing time synchronization according to the type of the synchronization request.

[0065] In the step 102, the entanglement distribution network includes a plurality of control centers, time reference nodes connected with the control centers, and to-be-synchronized nodes. In some optional embodiments, before synchronizing the base clock of any of the to-be-synchronized nodes through a time synchronization protocol according to the clock source, a network topology graph as shown in the following figure is established based on a preset entanglement distribution distance, and time synchronization is performed according to the network topology graph. Figure 2 In the figure, S1-S8 are control nodes, A, B, and C are source and sink nodes, the control nodes S1-S8 are connected with each other, the nodes A and C are connected with the control center S1, and the node B is connected with the control center S5. Figure 2 In the figure, S1-S8 are control nodes, A, B, and C are source and sink nodes, the control nodes S1-S8 are connected with each other, the nodes A and C are connected with the control center S1, and the node B is connected with the control center S5.

[0066] Further, the time synchronization protocol is a PTP protocol or an NTP protocol or other time synchronization protocols with equivalent effects. The PTP is a precise time protocol, which is a protocol for synchronizing clocks in the entire computer network. The NTP is a network time protocol, which is used for clock synchronization between computer systems through a variable delay data network of packet exchange.

[0067] In some optional embodiments, the time synchronization according to the type of the synchronization request includes: in response to determining that the type of the synchronization request is that the to-be-synchronized node performs time synchronization with any of the control centers, calculating the time difference between the to-be-synchronized node and the control center, and performing time synchronization according to the time difference; in response to determining that the type of the synchronization request is that the to-be-synchronized source and sink node performs time synchronization with the time reference source and sink node belonging to the same control center, calculating the time difference between the to-be-synchronized source and sink node and the time reference node, and performing time synchronization according to the time difference; and in response to determining that the type of the synchronization request is that the to-be-synchronized node performs time synchronization with other nodes across the control centers, calculating the time difference between the to-be-synchronized node and the time reference node across the control centers, and correcting the clock of the to-be-synchronized node according to the time difference, so that the to-be-synchronized node and the time reference node achieve time synchronization.

[0068] In some optional embodiments, the step of performing time synchronization according to the time difference comprises: in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and any of the control centers, determining a first entangled state particle and a second entangled state particle by an EPR source, and distributing the first entangled state particle and the second entangled state particle to the to-be-synchronized node and the control center, respectively; wherein the first entangled state particle and the second entangled state particle are mutually entangled; establishing a communication channel between the to-be-synchronized node and the control center according to the first entangled state particle and the second entangled state particle; receiving a time synchronization message by the to-be-synchronized node through the communication channel, and obtaining a current timestamp, determining a probability distribution of a first superposition state of the first entangled state particle in the to-be-synchronized node according to the current timestamp; determining a time difference between the to-be-synchronized node and the control center according to the probability distribution of the first superposition state of the first entangled state particle; and correcting a clock of the to-be-synchronized node according to the time difference, so as to realize time synchronization between the to-be-synchronized node and the control center.

[0069] Specifically, according to the topology graph as shown in Figure 2 , when it is determined that node C is a to-be-synchronized node and node A is a time reference node, and node A and node C are connected to control center S1, and according to the connection condition, a synchronization topology graph as shown in Figure 3 is determined, which is a first synchronization topology graph of the application. Referring to the flow chart as shown in Figure 4 , when it is determined that a synchronization service arrives at the to-be-synchronized node, a pair of entangled states is prepared by using an EPR source for node C and control center S1, particle 1 is sent to the to-be-synchronized node C, and particle 2 is sent to control center S1, that is, node C and control center S1 share the same pair of entangled state particles, and a quantum channel between the to-be-synchronized node C and control center S1 is established. Further, control center S1 performs joint Bell measurement on the particle 2 held by itself at t S1 =0 of the clock of itself, the quantum state collapses, and starts to evolve with time; at the same time, since particles 1 and 2 are mutually entangled, the quantum state of particle 1 held by node C also collapses and starts to evolve with time. Then, control center S1 sends a time synchronization message to the to-be-synchronized node C through a classical channel, and the timestamp record information t S1 .

[0070] Further, the to-be-synchronized node performs measurement on the quantum state of the particle 1 held by itself at t C =0 of the clock of itself (assuming later than t S1 ), and the probability distribution of particle 1 in |±> state is Δt=tS1 -t C Calculate the probability of particle 1 being in the positions |+> and |-> and obtain Δt. Modify the time t of particle 1. C =t C +Δt, completing synchronization with control center S1. Here, |±> represents a superposition state, i.e., the first and second superposition states mentioned above; |+> represents the ground state; and |-> represents the excited state. It should be noted that the terms "first" and "second" in the first and second superposition states in this application do not have any technical meaning, but are merely used to distinguish between the two superposition states.

[0071] In some alternative implementations, refer to, for example Figure 3 The flowchart shown illustrates that, in response to the determination that neither node C nor control center S1 has received entangled particles (i.e., particle distribution failed), a feedback indicating unsuccessful distribution is sent to the time reference node. Once the time reference node receives the feedback indicating unsuccessful distribution, it re-distributes the particles.

[0072] In some optional implementations, the step of responding to determining that the type of the synchronization request is time synchronization between the node to be synchronized and a target time reference node belonging to the same control center, calculating the time difference between the node to be synchronized and the target time reference node, and performing time synchronization based on the time difference includes: responding to determining that the type of the synchronization request is time synchronization between the source and destination nodes to be synchronized and the time reference node, determining a first entangled pair and a second entangled pair through an EPR source; wherein, the first entangled pair includes a third entangled particle, a fourth entangled particle, a fifth entangled particle, and a sixth entangled particle; distributing the third entangled particle to the time reference node, and the fourth entangled particle... The fifth entangled particle and the sixth entangled particle are distributed to the control center, and the sixth entangled particle is distributed to the node to be synchronized, establishing a communication channel between the node to be synchronized, the time reference node, and the control center. The node to be synchronized receives a time synchronization message through the communication channel and obtains the current timestamp. Based on the current timestamp, it determines the probability distribution of the superposition state of the sixth entangled particle in the node to be synchronized. Based on the probability distribution of the superposition state of the sixth entangled particle, it determines the time difference between the node to be synchronized and the time reference node. Based on the time difference, it corrects the clock of the node to be synchronized to achieve time synchronization between the node to be synchronized and the time reference node.

[0073] Specifically, according to, for example Figure 2 In the topology diagram shown, when the time reference node is determined to be node A, the node to be synchronized is node C, and S1 is the control center connecting the time reference node A and the node to be synchronized C, the following is determined based on the connection situation: Figure 5 The synchronization topology diagram shown is the second synchronization topology diagram of this application. See reference...Figure 6 The flow chart shows that when it is determined that the synchronization service arrives at the node to be synchronized, the entangled pairs containing entangled particles are distributed between the control center S1 and the node to which it belongs, and a quantum channel is constructed. Among them, the first entangled pair includes particles 3 and 4, and the second entangled pair includes particles 5 and 6. Particles 4 and 5 are distributed to the control center S1, and particles 3 and 6 are respectively distributed to the time reference node A and the node to be synchronized C. In response to the determination that both the node to be synchronized (A, C node) and the control center S1 determine that the entangled particles are received, the S1 and the node A, C quantum channel is successfully established, and the next step of time synchronization is performed.

[0074] Further, as Figure 2 The topology diagram shows that when the synchronization service arrives at the node to be synchronized C, the node to be synchronized C sends a synchronization request to the control center S1, and it is detected that the node to be synchronized C needs to be synchronized with the time reference node A which also belongs to the control center S1. In the case that the particle distribution is successful and the channel is safe, the joint Bell base measurement is performed on particles 4 and 5 at the control center S1, and then the particles 6 and 3 held by the node to be synchronized C and the particles 4 and 5 held by the control center S1 will be entangled. The time reference node A measures the particle 1 held by itself at the time t A = 0, and the quantum state collapses and starts to evolve with time; at the same time, since the particles 3 and 6 are entangled with each other, the quantum state of the particle 6 held by the node C also collapses and starts to evolve with time. Among them, the time reference node A sends a time synchronization message to the node to be synchronized C through a classical channel, and records the time stamp information t A .

[0075] It should be noted that the joint Bell base measurement is to make the particles that are not entangled entangled. For example, there are two nodes Alice and Bob, and initially the two particles A1 and A2 on the node Alice are entangled, and the two particles B1 and B2 on the other node Bob are also entangled, but the particles between Alice and Bob are not entangled. Alice and Bob can respectively send the two particles A2 and B2 (usually photons) to a designated place for Bell base measurement. By measuring and consuming the two particles A2 and B2, the two particles A1 and B1 originally not entangled at different nodes can be entangled.

[0076] Further, the node to be synchronized C measures the quantum state of the particle 6 held by itself at the time t C = 0 (assuming later than t A ), and the probability distribution of the particle 6 in the state |±> is Δt = t A -t CThe probabilities of the states |+> and |-> of the particle 6 are calculated, and Δt is calculated. The time at C is modified according to Δt, and the specific modification method is t C = t C + Δt, thereby completing synchronization with the time reference node A.

[0077] In some optional embodiments, as shown in the flow chart of Figure 6 When it is determined that the entangled state particles are not received by the nodes A and C to be synchronized and the control center S1, i.e., the particle distribution is unsuccessful, a feedback of unsuccessful distribution is sent to the time reference node, and the particle distribution is re-performed after the time reference node receives the feedback of unsuccessful distribution.

[0078] In some optional embodiments, in response to determining that the type of the synchronization request is that the node to be synchronized performs time synchronization with other nodes across the control center, the time difference between the node to be synchronized and the other source and sink nodes is calculated, and the clock of the node to be synchronized is corrected according to the time difference, so that the node to be synchronized and the time reference node achieve time synchronization, comprising:

[0079] In response to determining that the type of the synchronization request is that the node to be synchronized performs time synchronization with the time reference node, a plurality of entangled state particles are determined by an EPR source, and the plurality of entangled state particles are respectively distributed to the node to be synchronized, the other nodes, and a plurality of the control center; wherein the node to be synchronized and the time reference node respectively distribute one entangled state particle, and any control center distributes two entangled state particles; according to the plurality of entangled state particles, the node to be synchronized, the time reference node, and the control center, a communication channel of the node to be synchronized, the time reference node, and the control center is established; the node to be synchronized receives a time synchronization message through the communication channel and obtains a current timestamp, determines the probability distribution of the superposition state of the entangled state particle corresponding to the node to be synchronized according to the current timestamp; according to the probability distribution of the entangled state particle, the time difference between the node to be synchronized and the control center is determined; the clock of the node to be synchronized is corrected according to the time difference, so that the node to be synchronized and the other nodes are time-synchronized.

[0080] Specifically, according to the topology graph as shown in Figure 2 When it is determined that the time reference node is node C and the node to be synchronized is node B, the shortest path between the time reference node C and the node to be synchronized B is determined, and according to the topology graph as shown in Figure 2 It can be seen that the path from the time reference node C to the node B through the control centers S1, S3, and S5 has the least nodes and the shortest path, and the connection between the nodes and the control centers is determined as Figure 7The synchronization topology shown is the third synchronization topology of the present application. Referring to the flowchart shown, Figure 8 The flowchart shown, when determining that the synchronization service arrives at the node to be synchronized, determines the number of control centers, and determines the EPR source of the prepared particles according to the number of control centers. Wherein, the number of EPR sources is one more than the number of control centers, that is, when the number of EPR sources is n, the number of control centers is n+1, therefore, in the present application, the number of control centers is 3, and the number of EPR sources is 4, each EPR source includes 2 particles, so there are particles 1, 2, 3, 4, 5, 6, 7, 8, a total of 8 particles, and particles 1, 2 are respectively distributed to the control center S1 of the node to be synchronized C and the time reference node B, particles 3, 4 are distributed to the control centers S1, S2, and finally the 7th and 8th particles are distributed to the control center S3 and the time reference node B, thereby forming a quantum channel between the nodes.

[0081] In some optional embodiments, after the distribution of the particles is completed, it is detected whether each pair of particles is successfully distributed, it is determined that the distribution of the particles is successful, and then the node to be synchronized is time-synchronized according to the particles. The time synchronization specifically includes: respectively performing joint Bell basis measurement on the particles held by each control center S1, S3, S5, and finally causing the particles 1 and 8 held by the node to be synchronized C and the time reference node B to be entangled. The time reference node B measures the particle 8 held by itself at the time t B =0 of its own clock, the quantum state collapses, and starts to evolve with time; at the same time, since the particles 1 and 8 are mutually entangled, the quantum state of the particle 1 also collapses and starts to evolve with time. At the same time, the time reference node B sends a time synchronization message to the node to be synchronized C through a classical channel, and the time stamp records information t B .

[0082] Further, the node to be synchronized C measures the quantum state of the particle 1 held by itself at the time t C =0 of its own clock (assuming later than t B ), the probability distribution of the particle 1 in the superposition state is Δt=t B -t C , and the probability of the particle 1 in the ground state and the excited state is calculated to obtain Δt, and the time t C of the node to be synchronized C is modified to t C +Δt, thereby completing synchronization with the time reference node B.

[0083] In some optional embodiments, referring to the flowchart shown, Figure 8In response to determining that the entangled state particles are not received by the nodes A, B and the control centers S1, S3 and S5, i.e., the distribution of the entangled state particles is unsuccessful, the flowchart shows that the time reference node is fed back with a feedback of unsuccessful distribution, and the time reference node re-distributes the entangled state particles after receiving the feedback of unsuccessful distribution.

[0084] As can be seen from the above, the entanglement distribution network in the time synchronization method between source and sink nodes provided by the application comprises a plurality of control centers, and time reference nodes and nodes to be synchronized connected with the control centers. Specifically, the method comprises: judging the synchronization service type of the node with synchronization demand through the control center, and adopting the corresponding entanglement distribution or entanglement exchange method to complete the end-to-end time synchronization service between users in the entanglement distribution network. Based on different synchronization demands of the nodes, the method adopts different entanglement distribution or entanglement exchange methods through the judgment of the control center, realizes the time synchronization between the nodes, and further realizes the network synchronization of the network, and has the advantages of long synchronization distance, high synchronization precision, and high security.

[0085] It should be noted that the method of the embodiments of the application can be executed by a single device, such as a computer or a server. The method of the embodiments can also be applied to a distributed scenario, and be completed by multiple devices cooperating with each other. In the case of the distributed scenario, one of the multiple devices can only execute one or more steps in the method of the embodiments of the application, and the multiple devices can interact with each other to complete the method.

[0086] It should be noted that some embodiments of the application have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than the order described above and still achieve desirable results. In addition, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0087] Based on the same inventive concept, the application also provides an entanglement distribution network time synchronization device between source and sink nodes corresponding to any of the above-mentioned embodiment methods.

[0088] Reference Figure 9 The entanglement distribution network time synchronization device between source and sink nodes comprises:

[0089] The determination module 901 is configured to determine the clock source of the entanglement distribution network.

[0090] The first synchronization module 902 is configured to perform initial synchronization of a base clock of any of the source and sink nodes according to the clock source through a time synchronization protocol.

[0091] The second synchronization module 903 is configured to determine a source and sink node to be synchronized, receive a synchronization request of the source and sink node to be synchronized, determine a type of the synchronization request, and perform time synchronization according to the type of the synchronization request.

[0092] In some embodiments, the first synchronization module 902 is further configured to:

[0093] establish a network topology graph of the plurality of the source and sink nodes to be synchronized based on a preset entanglement distribution distance.

[0094] In some embodiments, the second synchronization module 903 is configured to:

[0095] in response to determining that the type of the synchronization request is time synchronization of the source and sink node to be synchronized with any of the control centers, calculate a time difference between the source and sink node to be synchronized and the control center, and perform time synchronization according to the time difference and the network topology graph;

[0096] in response to determining that the type of the synchronization request is time synchronization of the source and sink node to be synchronized with a time reference node belonging to the same control center, calculate a time difference between the source and sink node to be synchronized and the time reference node, and perform time synchronization according to the time difference and the network topology graph;

[0097] in response to determining that the type of the synchronization request is time synchronization of the source and sink node to be synchronized with a time reference node across control centers, calculate a time difference between the source and sink node to be synchronized and the time reference node, and correct a clock of the source and sink node to be synchronized according to the time difference and the network topology graph, so that the source and sink node to be synchronized and the time reference node achieve time synchronization.

[0098] In some embodiments, the second synchronization module 903 is configured to:

[0099] in response to determining that the type of the synchronization request is time synchronization of the source and sink node to be synchronized with any of the control centers, determine a first synchronization topology graph according to the network topology graph;

[0100] determine a first entangled state particle and a second entangled state particle through an EPR source, and distribute the first entangled state particle and the second entangled state particle to the source and sink node to be synchronized and the control center respectively according to the first synchronization topology graph, wherein the first entangled state particle and the second entangled state particle are entangled with each other;

[0101] establish a communication channel between the source and sink node to be synchronized and the control center according to the first entangled state particle and the second entangled state particle.

[0102] receiving, by the to-be-synchronized node, a time synchronization message through the communication channel, and obtaining a current timestamp, and determining a probability distribution of a first superposition state of the first entangled state particle in the to-be-synchronized node according to the current timestamp;

[0103] determining a time difference between the to-be-synchronized node and the time reference node according to the probability distribution of the first superposition state of the first entangled state particle;

[0104] modifying a clock of the to-be-synchronized node according to the time difference, so as to realize time synchronization between the to-be-synchronized node and the time reference node.

[0105] In some embodiments, the second synchronization module 903 is configured to:

[0106] determining a second synchronization topology graph according to the network topology graph, in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and the time reference node;

[0107] determining a first entangled pair and a second entangled pair through an EPR source, and distributing the third entangled state particle to the time reference node, the fourth entangled state particle and the fifth entangled state particle to the control center, and the sixth entangled state particle to the to-be-synchronized node according to the second synchronization topology graph, and establishing a communication channel between the to-be-synchronized node, the time reference node and the control center in response to determining that the distribution is successful; wherein the first entangled pair includes a third entangled state particle and a fourth entangled state particle, the second entangled pair includes a fifth entangled state particle and a sixth entangled state particle;

[0108] receiving, by the to-be-synchronized node, a time synchronization message through the communication channel, and obtaining a current timestamp, and determining a probability distribution of a first superposition state of the first entangled state particle in the to-be-synchronized node according to the current timestamp;

[0109] determining a time difference between the to-be-synchronized node and the time reference node according to the probability distribution of the first superposition state of the first entangled state particle;

[0110] modifying a clock of the to-be-synchronized node according to the time difference, so as to realize time synchronization between the to-be-synchronized node and the time reference node.

[0111] In some embodiments, the second synchronization module 903 is configured to:

[0112] determining a third synchronization topology graph according to the network topology graph, in response to determining that the type of the synchronization request is time synchronization between the to-be-synchronized node and the time reference node;

[0113] determining a plurality of EPR sources according to the number of the control centers in the third synchronization topology; determining a plurality of entangled state particles through the EPR sources, and distributing the plurality of entangled state particles to the to-be-synchronized nodes, the time reference node, and the plurality of control centers respectively; wherein the to-be-synchronized nodes and the time reference node distribute one entangled state particle respectively, and any control center distributes two entangled state particles;

[0114] establishing a communication channel of the to-be-synchronized nodes, the time reference node, and the control centers according to the plurality of entangled state particles, the to-be-synchronized nodes, the time reference node, and the control centers;

[0115] The to-be-synchronized nodes receive a time synchronization message through the communication channel, and obtain a current time stamp, and determine a probability distribution of a third superposition state of the entangled state particle corresponding to the to-be-synchronized nodes according to the current time stamp;

[0116] determining a time difference between the to-be-synchronized nodes and the control centers according to the probability distribution of the entangled state particles;

[0117] modifying a clock of the to-be-synchronized nodes according to the time difference, so as to realize time synchronization between the to-be-synchronized nodes and the time reference node.

[0118] In some embodiments, the second synchronization module 903 is further configured to:

[0119] The time synchronization protocol is a PTP protocol or an NTP protocol.

[0120] For the convenience of description, the above apparatus is described in various modules respectively according to functions. Of course, in the implementation of the present application, the functions of the modules can be implemented in one or more software and / or hardware.

[0121] The apparatus of the above embodiments is used to implement the time synchronization method between source and sink nodes in the entanglement distribution network in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which are not described here again.

[0122] Based on the same inventive concept, the present application also provides an electronic device corresponding to the method of any of the above embodiments, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the time synchronization method between source and sink nodes in the entanglement distribution network according to any of the above embodiments when executing the program.

[0123] Figure 10A more specific electronic device hardware structure schematic diagram provided by the embodiment is shown, and the device can include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 for internal communication.

[0124] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits, etc., for executing related programs to implement the technical solutions provided by the embodiments of the present specification.

[0125] The memory 1020 can be implemented by a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, etc. The memory 1020 can store an operating system and other application programs, and when the technical solutions provided by the embodiments of the present specification are implemented by software or firmware, the related program codes are stored in the memory 1020 and called and executed by the processor 1010.

[0126] The input / output interface 1030 is used to connect input / output modules to realize information input and output. The input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. The input device can include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device can include a display, a speaker, a vibrator, an indicator light, etc.

[0127] The communication interface 1040 is used to connect a communication module (not shown in the figure) to realize the communication interaction between the device and other devices. The communication module can realize communication through a wired manner (such as USB, network cable, etc.) or through a wireless manner (such as mobile network, WIFI, Bluetooth, etc.).

[0128] The bus 1050 includes a channel for transmitting information between various components (such as the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040) of the device.

[0129] It should be noted that although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, but in the specific implementation process, the device can also include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device can also only contain the components necessary to implement the embodiments of the present application, and does not have to contain all the components shown in the figure.

[0130] The electronic device of the above embodiment is used to implement the time synchronization method between source and sink nodes in the entanglement distribution network in any of the preceding embodiments, and has the beneficial effects of the corresponding method embodiments, which are not described here.

[0131] Based on the same inventive concept, corresponding to the method of any of the above embodiments, the present application also provides a non-transitory computer readable storage medium storing computer instructions for causing the computer to perform the time synchronization method between source and sink nodes in the entanglement distribution network as described in any of the above embodiments.

[0132] The computer readable medium of the present embodiment includes permanent and non-permanent, removable and non-removable media, which can be implemented by any method or technology to store information. The information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0133] The computer instructions stored in the storage medium of the above embodiment are used to cause the computer to perform the time synchronization method between source and sink nodes in the entanglement distribution network as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which are not described here.

[0134] Those skilled in the art should understand that the above discussion of any of the embodiments is only exemplary and is not intended to limit the scope of the present application (including claims) to these examples; under the idea of the present application, the above embodiments or technical features in different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the embodiments of the present application as described above. In order to be brief, they are not provided in detail.

[0135] In addition, to simplify the description and discussion, and so as not to obscure the embodiments of the application with details that are well known to those skilled in the art, some conventional attributes of integrated circuit (IC) chips and other components can or can not be shown in the drawings and can not be described. Furthermore, devices can be shown in block diagram form in order to avoid obscuring the embodiments of the application, and this also acknowledges the fact that the details in regard to how such block devices are implemented are highly dependent on the platform within which the embodiments of the application are being implemented (i.e., such details should be readily apparent to those skilled in the art). Where specific details are set forth in order to describe an illustrative embodiment of the application, it should be apparent to those skilled in the art that the embodiment described can not specifically address some nuances, or options or modifications, etc. that can be significant in a non-illustrative embodiment. The description is thus to be considered in all respects as illustrative and not restrictive.

[0136] While the application has been described in connection with specific embodiments thereof, it will be understood that many modifications, substitutions and changes can be made by those skilled in the art without departing from the spirit and scope of the present application. For example, other memory architectures (e.g., dynamic RAM (DRAM)) can use the embodiments discussed.

[0137] It is intended that the embodiments of the present application encompass all such substitutions, modifications and variations as fall within the broad scope of the appended claims. Accordingly, any and all such modifications, variations or equivalents that fall within the spirit and scope of the present application should be intended to be embraced by the claims.

Claims

1. A method for time synchronization of source and destination nodes in an entangled distribution network, characterized in that, The source and destination nodes include a source node and a destination node. The source node is a network node that sends the original data packet, and the destination node is a network node that receives the data packet. The entanglement distribution network includes several control centers, as well as a time reference node and a node to be synchronized connected to the control centers. The time reference node is the source node, and the node to be synchronized is the destination node. The method includes: Determine the clock source of the entanglement distribution network; A network topology diagram of multiple nodes to be synchronized is established based on a preset entanglement distribution distance; Based on the clock source, the base clock of any of the nodes to be synchronized is initially synchronized using a time synchronization protocol. The process involves identifying the node to be synchronized, receiving a synchronization request from the node to be synchronized, determining the type of the synchronization request, and performing time synchronization based on the type of the synchronization request; wherein, performing time synchronization based on the type of the synchronization request includes: In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and any of the control centers, the time difference between the node to be synchronized and the control center is calculated, and time synchronization is performed based on the time difference and the network topology diagram; In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and a time reference node belonging to the same control center, the time difference between the node to be synchronized and the time reference node is calculated, and time synchronization is performed according to the time difference and the network topology. In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and the time reference node across control centers, the time difference between the node to be synchronized and the time reference node is calculated, and the clock of the node to be synchronized is corrected according to the time difference and the network topology diagram, so that the node to be synchronized and the time reference node can achieve time synchronization.

2. The method according to claim 1, characterized in that, The response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and any of the control centers, calculating the time difference between the node to be synchronized and the control center, and performing time synchronization based on the time difference and the network topology diagram includes: In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and any of the control centers, a first synchronization topology is determined based on the network topology. The first entangled particle and the second entangled particle are determined by the EPR source, and the first entangled particle and the second entangled particle are distributed to the node to be synchronized and the control center respectively according to the first synchronization topology graph; wherein the first entangled particle and the second entangled particle are mutually entangled; A communication channel is established between the node to be synchronized and the control center based on the first entangled particle and the second entangled particle. The node to be synchronized receives a time synchronization message through the communication channel and obtains the current timestamp. Based on the current timestamp, it determines the probability distribution of the first superposition state of the first entangled particles in the node to be synchronized. The time difference between the node to be synchronized and the control center is determined based on the probability distribution of the first superposition state of the first entangled particles. The clock of the node to be synchronized is corrected based on the time difference to achieve time synchronization between the node to be synchronized and the control center.

3. The method according to claim 1, characterized in that, The response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and a time reference node belonging to the same control center, calculating the time difference between the node to be synchronized and the time reference node, and performing time synchronization based on the time difference and the network topology diagram includes: In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and the time reference node, a second synchronization topology is determined based on the network topology diagram; The first entangled pair and the second entangled pair are determined by the EPR source; wherein the first entangled pair includes a third entangled particle and a fourth entangled particle, and the second entangled pair includes a fifth entangled particle and a sixth entangled particle; According to the second synchronization topology, the third entangled particle is distributed to the time reference node, the fourth and fifth entangled particles are distributed to the control center, and the sixth entangled particle is distributed to the node to be synchronized. In response to the successful distribution, a communication channel is established between the node to be synchronized, the time reference node, and the control center. The node to be synchronized receives a time synchronization message through the communication channel and obtains the current timestamp. Based on the current timestamp, it determines the probability distribution of the second superposition state of the sixth entangled particle in the node to be synchronized. Based on the probability distribution of the sixth entangled state particle, the time difference between the node to be synchronized and the time reference node is determined; The clock of the node to be synchronized is corrected based on the time difference to achieve time synchronization between the node to be synchronized and the time reference node.

4. The method according to claim 1, characterized in that, The response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and the time reference node across control centers, calculating the time difference between the node to be synchronized and the time reference node, and correcting the clock of the node to be synchronized based on the time difference and the network topology diagram to achieve time synchronization between the node to be synchronized and the time reference node includes: Determine the number of control centers, and in response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and the time reference node, determine a third synchronization topology based on the network topology diagram; Based on the number of control centers in the third synchronization topology diagram, several EPR sources are determined; several entangled particles are determined through the EPR sources, and the several entangled particles are distributed to the node to be synchronized, the time reference node, and the several control centers respectively; wherein, the node to be synchronized and the time reference node each distribute one entangled particle, and any one of the control centers distributes two entangled particles; A communication channel is established between the entangled particles, the node to be synchronized, the time reference node, and the control center. The node to be synchronized receives a time synchronization message through the communication channel and obtains the current timestamp. Based on the current timestamp, it determines the probability distribution of the third superposition state of the entangled particles corresponding to the node to be synchronized. Based on the probability distribution of the entangled particles, the time difference between the node to be synchronized and the control center is determined; The clock of the node to be synchronized is corrected based on the time difference to achieve time synchronization between the node to be synchronized and the time reference node.

5. The method according to claim 1, characterized in that, The method includes: The time synchronization protocol is either PTP or NTP.

6. A source-destination node time synchronization device in an entangled distribution network, characterized in that, The source and destination nodes include a source node and a destination node. The source node is a network node that sends the original data packet, and the destination node is a network node that receives the data packet. The entanglement distribution network includes several control centers, as well as a time reference node and a node to be synchronized connected to the control centers. The time reference node is the source node, and the node to be synchronized is the destination node. The device includes: The determination module is configured to determine the clock source of the entanglement distribution network and establish a network topology map of multiple nodes to be synchronized based on a preset entanglement distribution distance. The first synchronization module is configured to perform initial synchronization of the base clock of any of the nodes to be synchronized according to the clock source and through a time synchronization protocol. The second synchronization module is configured to determine the node to be synchronized, receive a synchronization request from the node to be synchronized, determine the type of the synchronization request, and perform time synchronization according to the type of the synchronization request; wherein, performing time synchronization according to the type of the synchronization request includes: In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and any of the control centers, the time difference between the node to be synchronized and the control center is calculated, and time synchronization is performed based on the time difference and the network topology diagram; In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and a time reference node belonging to the same control center, the time difference between the node to be synchronized and the time reference node is calculated, and time synchronization is performed according to the time difference and the network topology. In response to determining that the type of the synchronization request is time synchronization between the node to be synchronized and the time reference node across control centers, the time difference between the node to be synchronized and the time reference node is calculated, and the clock of the node to be synchronized is corrected according to the time difference and the network topology diagram, so that the node to be synchronized and the time reference node can achieve time synchronization.

7. An electronic device, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor, when executing the computer program, implements the method according to any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions for causing the computer to perform the method according to any one of claims 1 to 5.

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