TWI469547B - A quantum entanglement establishment method - Google Patents

Description

Quantum entangled state construction method

The invention relates to a quantum entangled state construction method, in particular to a method for sharing the same set of quantum entangled states in a quantum network by allowing different clients to assist via a server.

According to the evolution trend of semiconductor technology (for example, size reduction, etc.), the behavior of information processing media (such as electrons or photons) has gradually operated according to the characteristics of Quantum. As a result, the conventional information processing method will no longer be fully applicable. Instead, Quantum Information Science (QIS), derived from quantum physics and information science, is a new field of information processing and traditional information processing. Very different, the relevant literature is listed below.

Table 1 List of related articles in quantum information science

It can be seen from the related literature shown in Table 1 that Quantum Network, Quantum Computer, Quantum Communication can be derived by using quantum state changes of atoms, electrons or photons. Applications of quantum information science such as Quantum Teleportation or Quantum Cryptography.

Moreover, because the traditional information science's traditional bit (Classical Bit) can only be in a state other than 0 or 1, the quantum information science quantum bit (Quant, Qubit, hereinafter referred to as quantum) can be in the state at the same time | 0> and |1>, so that different information can be recorded using quantum superposition and coherence, for example, using a tensor product (Tensor Product, ) Calculate the superposition, so the configuration using quantum recording information will be more than the configuration using traditional bits. Furthermore, since any observation behavior for quantum will immediately change the state of the quantum, it can be used to determine whether the state of the quantum has been eavesdropped (ie, measured) to ensure the absolute security of the information.

It is worth noting that in quantum computing technology, the quantum stored in the scratchpad can be measured, for example, Bell Measurement, etc., and the quantum has an entangled state with each other, for example: photon pole Chemical characteristics or phase |0>±|1>, etc., these quantum (at least two) with entangled states have strong correlation, when one of the quantum states is changed or measured, all other bit states will Corresponding changes, this feature can be applied to applications such as quantum computing or quantum computers.

Conventional quantum computers can be broadly classified into technical solutions using cold-bound ion traps, atomic and optical cavity interactions, electron or nuclear spin resonance, quantum dot manipulation, or superconducting Josephine junctions. In addition, the conventional quantum communication system comprises a quantum state generator, a classical channel, a quantum channel, and a quantum state receiver, wherein the quantum state a generator (eg, a polarized photon random generator, etc.) for generating photons having different quantum states; the conventional channel (eg, an optical fiber, etc.) is used to transmit a check between the quantum state generator and the quantum state receiver for verification Information; the quantum channel (eg, fiber optics, etc.) is used to transmit the photons having different quantum states to the quantum state receiver; the quantum state receiver (eg, a single photon detector) is used to detect the quantum state of the photon. Therefore, a conventional computer or quantum computer can be combined with a quantum communication system to form a conventional quantum network.

In the conventional quantum network, when several users want to perform applications such as quantum operations or transmission, they need to share the same set of quantum entangled states (Entanglement, or entangled states). However, since the quantum state is atomic or Other micro-particles are formed, which are easily affected by noise from the external environment, causing the quantum coherence to disappear (or decoherence). Therefore, it is easy to produce a mass change during quantum transmission, making the quantum entangled state difficult to be long distance (for example: greater than 40 km) Maintenance, it is prone to errors in the processing results of quantum information.

In order to solve the problem of information processing of the above quantum network, domestic and foreign industry and academia have not invested a large amount of money for research and development, and some solutions have been developed at present. Several representative practices are described below:

Referring to FIG. 1a, it is a first conventional quantum entanglement state construction method in which a source end (for example, a device having a quantum state generator) E1 and a destination end (for example, having quantum state reception) Between the devices E2, a plurality of relay terminals (for example, quantum repeaters) R1, ..., Rn are connected in series by a conventional channel and a quantum channel (not shown). When the source end E1 and the destination end E2 want to share a set of quantum entangled states, two quantum q having an entangled state are first generated by the source end E1, and one of the two quasi-qu q is transmitted to the relay end R1. The quantum q is successively transmitted by the relay terminals R1, . . . , Rn to the destination end E2. However, in the transmission process, the quantum q is liable to undergo a qualitative change due to energy dissipation.

Please refer to FIG. 1b, which is a second conventional quantum entanglement state construction method, in which a server (Server, for example, a device with a quantum state generator) V and a plurality of clients (Client, for example : a device with a quantum state receiver) forms a Hierarchical Network Structure between C1, C2, ..., Cn, and the server V and each client C1, C2, ..., Cn They need to be connected to each other by traditional channels and quantum channels. When each client C1, C2, ..., Cn wants to share a set of quantum entangled states with each other, it is necessary for the servo terminal V to first generate a plurality of quantum q1, q2, ..., qn having entangled states, and then respectively One of the quantum q1, q2, ..., qn is transmitted to each of the clients C1, C2, ..., Cn. When at least two need to establish a quantum entangled state, all the transmission nodes (ie, the server V and each of the clients C1, C2, ..., Cn) must have available channels between them, but in the existing network This is not the case with cabling, so quantum routing is not possible with existing network cabling (eg, fiber optic networks) and will increase the cost of required channel construction. Moreover, due to the disconnection or congestion of the network, there is no channel between all the transmission nodes. For example, there may not be any available channels between the server V and the client Cn, causing the quantum. q cannot be transferred to the client Cn.

Please refer to FIG. 1c, which is a third conventional quantum entanglement state construction method, in which a source terminal (for example, a device having a quantum state generator) E1 and a destination end (for example, a quantum state receiver) Between the devices E2, a plurality of servo terminals (for example, devices having a quantum state generator and a quantum state receiver) V1, ..., Vn are connected in series by a conventional channel and a quantum channel. When the source end E1 and the destination end E2 want to share a set of quantum entangled states, a Quantum Entanglement Swapping process is required, and two sources q0 and q0' having entangled states are first generated by the source E1. Transmitting the quantum q0' to the servo terminal V1, the quantum terminals q1 and q1' having the entangled state are generated by the servo terminal V1, and the quantum q1 and the quantum q0' are mutually generated with an Entanglement State, for example: The quantum q1 and q0' are subjected to Bell measurement, etc., and the quantum terminal q1' is transmitted to the next servo terminal by the servo terminal V1, so that each of the servo terminals sequentially performs the quantum generation, entanglement, transmission, and the like. The quantum entangled state build operation, and finally, a quantum qn' is transmitted from the servo terminal Vn to the destination end E2. However, each of the servo terminals V1, . . . , Vn sequentially performs the quantum entanglement state setting operation, and when the number of the servo terminals V1, . . . , Vn is greatly increased, the quantum entangled state construction operation time is performed. It will grow in multiples, and when the network is disconnected or blocked, the destination end E2 may not receive the quantum qn'.

In summary, the conventional quantum entanglement state construction method not only causes "two pairs of channels exist between all transmission nodes", "cannot use existing network wiring for quantum transmission" and "quantum tangled state establishment operation time" Long, etc. Problems, and doubts such as "cannot receive quantum" and "quantum quality change", there are many limitations and shortcomings in actual use. It is inconvenient, and further improvement is needed to improve its practicability.

The object of the present invention is to improve the above disadvantages to provide a quantum entangled state construction method, by confirming that a transmission path between at least two of the entangled states is to be generated, so that there is no channel between the transmission nodes. Quantum can be transmitted via other channels.

A second object of the present invention is to provide a quantum entanglement state construction method for reducing quantum entanglement state construction time by parallel processing quantum generation, entanglement and transmission operations.

A quantum entangled state construction method is applied to a network environment, comprising: a path establishment step, wherein one of a plurality of sharing ends is used as an initiator, and the initiator uses a routing protocol to find a transmission path between each sharing end The transmission path is connected to the sharing end and the plurality of tangled ends, and the sharing end, the tangling end and the combination thereof are coupled to each other by a traditional channel and a quantum channel, and the initiator is weighted according to the routing protocol and the channel cost. Searching for the best path between the sharing end and the tangled end to form a minimum spanning tree and finding the longest path in the minimum spanning tree as the transmission path; a hierarchical establishment step is performed by the initiator The sharing end, the connection relationship between the tangled end and the transmission path confirms that the sharing end and the tangled end form a hierarchical structure, and then the tangled end negotiates to determine the transmission direction of the transmission path; and a quantum transmission step A plurality of quantumes having entangled states are generated by the tangled end, so that the quantum is transmitted in parallel according to the transmission direction to each share end.

The hierarchy establishing step is performed by the initiator in the transmission path to find a mid-point, and the tangled end closest to the middle point is the top of the hierarchical structure, and the sharing end serves as the hierarchical structure. bottom.

The hierarchical establishment step is performed by the initiator in the transmission path, wherein the tangential end includes a root and a plurality of leaves, and the root of the tree is closest to one of the tangential ends of the middle point. The leaves are connected to the tangled ends of the sharing ends.

The sharing end, the tangling end and the combination thereof are coupled to each other by a traditional channel and a quantum channel, and the initiator calculates a distance midpoint as the middle vertices by using the channel distance between the sharing ends. .

Wherein, the quantum transmission step generates a quantum having an entangled state from the root of the tree, and transmits it to each leaf in parallel, and each leaf generates a quantum having an entangled state according to the received quantum, and transmits the generated quantum to each sharing end. .

Wherein the tangled end comprises at least one branch connected to a tangled end between the root of the tree and the leaf, the branch generating a quantum having an entangled state according to the received quantum, and transmitting the generated quantum to the same The connected leaves, the leaves connected by the branches generate quantum with entangled states according to the received quantum, and then transmit the generated quantum to the shared end of its connection.

Wherein, the quantum transmission step generates a quantum having an entangled state from each leaf, and transmits it to the sharing end and the root of the tree in parallel, and the received root generates an entangled state by the received root.

Wherein the tangled end comprises at least one branch attached to the tangled end between the root of the tree and the leaf, the branch producing a quantum having an entangled state and transmitted in parallel to the connected leaves and the root of the tree, The root of the tree The resulting quantum produces an entangled state, and the leaves connected by the branch generate quantum with entangled states based on the received quantum, and then transmit the generated quantum to the shared end of its connection.

Wherein, the tangled end performs two measurements on the two quantum, so that the quantum produces an entangled state.

Wherein, when any entangled end receives j(j>0) quantum and needs to transmit i(i≧1) quantum, then (i+j) quantum with entangled state is generated, as shown in the following formula: Where |Ψ> is the entangled state of quantum, For the tensor product; i of the above (i+j) quantums are transmitted to the sharing end or other tangled ends, and the remaining j of the above (i+j) quantums are compared with the received j quantum twos. Measure.

Wherein, when two quantums are measured by Bell, the entangled state of the quantum is as follows: Where |Φ ⁺ 〉 is one of the four Bell states.

Wherein, when two quantums are measured by Bell, the entangled state of the quantum is as follows: Where |Φ ^- 〉 is one of the four Bell states.

Wherein, when two quantums are measured by Bell, the entangled state of the quantum is as follows: Among them, |Ψ ⁺ 〉 is one of the four Bell states.

When two quantums are measured by Bell, the entangled state of the quantum is as follows: Among them, |Ψ ^- 〉 is one of the four Bell states.

Wherein, the tangled end performs GHZ measurement or GHZ like measurement on a plurality of quantum, so that the quantum generates an entangled state.

Wherein, when the tangled end receives j(j>0) quantum and needs to transmit i(i≧0) quantum, if i=0, the received j quantum is subjected to a GHZ measurement or GHZ Like measurement, if i≧1, then (i+1) quantum with entangled state, where i quantum is transmitted to the sharing end or other tangled end 2, and the remaining 1 quantum is compared with the received j quantum A GHZ measurement or GHZ like measurement.

When several quantums are subjected to GHZ measurement or GHZ like measurement, the entangled state of the quantum is as follows: Where |Ψ> is one of the m GHZ states or one of the m GHZ like states, k {0,1}, For the tensor product.

In addition to the root of the tree, the other tangled ends are respectively an internal node, and each internal node is connected to one parent node and x child nodes, and the x child nodes include another a internal node and (xa) external nodes. After each internal node receives the quantum from the a internal node and generates (x+1) quantum having the entangled state, the (x+1) quantum having the entangled state is a and the a The quantum of the internal node is measured by Bell, and then Transmitting (xa) of the (x+1)th quantum to the external node, and transmitting one of the (x+1)th quantum to the parent node, where x and a are both positive integers, And x is greater than a.

The parent node is the root of the tree or another internal node, and the external node is the sharing end.

Wherein, the entangled state of the (x+1) quantum is as follows: Where |Ψ> is the GHZ state or the GHZ like state, For the tensor product.

The tree root is connected to y child nodes, and the y child nodes include b internal nodes and (yb) external nodes, and the tree root receives the quantum from the b internal nodes, and generates y quantum with tangled states. Then, the quantum of the y quantum entangled states and the b internal nodes are measured by Bell, and then (yb) of the y quantum are transmitted to the external node, where y and b is a positive integer and y is greater than b.

The internal node is the other tangled end except the root of the tree, and the external node is the sharing end.

Wherein, the entangled states of the y quantum are as follows: Where |Ψ> is the GHZ state or the GHZ like state, For the tensor product.

The tangled end selects an entangled state capable of resisting noise according to the type of noise in the quantum transmission, wherein the noise type is phase fading noise or phase rotation noise.

The sharing end performs quantum communication according to the measurement results of the entangled states of the quantum according to the entangled ends.

Wherein, the quantum transmission process adopts a wiretapping inspection mechanism, and a transmitter selects the induced photons from the four single photons of |0>, |1>, |+>, and |->, and the induced photons are randomly inserted into the photon. After quantum, the quantum, the position, base and value of the induced photon are transmitted to a receiver.

Wherein, the quantum transmission process uses a quantum error correction code, and two distinct logical values are represented by single photons |0> and |1>.

The above and other objects, features and advantages of the present invention will become more <RTIgt; Coupling means a medium (such as photons or electrons) that is used to represent quantum states by means of physical circuits (eg, conventional channels and quantum channels, etc.), wireless communication, or a combination thereof. The details thereof can be understood by those having ordinary knowledge in the technical field to which the present invention pertains.

The "Minimum Spanning Tree" (MST) as described in the full text of the present invention means that if a point set and a line between points are given, and each line has a different weighting value, a piece can be found. The path is such that all points are connected, and the sum of all weighting values on the path is the smallest, the details of which are understood by those of ordinary skill in the art to which the present invention pertains.

Please refer to the figures 2a, 2b and 2c, which are schematic diagrams (1), (2) and (3) of the preferred embodiment of the quantum entangled state construction method of the present invention, wherein the sharing unit comprises a plurality of sharing ends (Sharing) End)1 and several tangled ends (Entanglement End) 2, the sharing end 1, the tangential end 2 and a combination thereof may adopt a conventional channel T and a quantum channel Q to be coupled to each other to form a quantum Quantum Network, each sharing device 1 includes a data processing and quantum receiving function for receiving a quantum (eg, photon) having an entangled state, and storing the state of the quantum for sharing by the user Terminal 1 performs related applications of quantum information science; the tangled end 2 includes means for data processing, quantum generation, and transceiving functions for generating a plurality of quantum with entangled states, receiving/transmitting the quantum, and causing several quantum to generate entangled states. The traditional channel and the quantum channel are respectively composed of materials capable of transmitting information and quantum states, and are used for transmitting communication information and quantum state between the sharing terminal 1 and the tangential terminal 2. In this embodiment, the two sharing ends 1 and the three tangling ends 2 are taken as the first embodiment (as shown in FIG. 2a); the other two sharing ends 1 and five tangled ends 2 are used as the first Two implementation aspects (as shown in Figure 2b); another three sharing ends 1 and five tangled ends 2 as a third implementation aspect (as shown in Figure 2c); wherein each sharing end 1 can A plurality of single photon detectors are electrically connected by a computer; the tangential end 2 can be electrically connected to a polarized photon random generator and a plurality of single photon detectors; the traditional channel and the quantum channel can be respectively formed by optical fibers. , but not limited to this.

Referring to FIG. 3, it is an operational flowchart of a preferred embodiment of the quantum entanglement state construction method of the present invention, which includes a path establishment step S1, a level establishment step S2, and a quantum transmission step S3.

The path establishing step S1 is performed by one of the plurality of sharing terminals 1 as an initiator, and the initiator uses a routing protocol to find between the sharing terminals 1 The transmission path is connected to each sharing end 1 and a plurality of tangential ends 2. In detail, when a plurality of sharing terminals 1 want to share the same quantum entanglement state (Quantum Entanglement State), any sharing end 1 (for example, sharing end 1a) can be used as the initiator, as shown in FIG. 2c. The initiator may use a routing protocol, for example, using a conventional distance vector algorithm or a routing protocol of a connection state algorithm to find a minimum spanning tree between the sharing end 1 and the tangling end 2 (Minimum) Spanning Tree, MST)M, and looking for the longest path in the minimum spanning tree M as the transmission path; or, as shown in FIG. 2b, the initiator can also use the routing protocol to find all the sharing terminals 1 and the tangling end 2 The best path is used as the transmission path. For example, the transmission path is searched according to the weighted value of each channel (ie, the traditional channel and the quantum channel). If the distance of each channel is longer, the weighting value of the channel cost can be set to be lower. The path with the lowest weighting value is taken as the transmission path.

The stratum establishes step S2, and the initiator confirms that the sharing end 1 and the tangled end 2 form a hierarchical architecture according to the connection relationship between the sharing end 1, the tangled end 2 and the transmission path. Then, the tangled end 2 negotiates to determine the transmission direction of the transmission path. In detail, first, the initiator confirms whether the shared end 1 and the tangled end 2 have formed the hierarchical structure according to the connection relationship between the transmission path and the sharing end 1 and the tangled end 2, if The hierarchical architecture, as shown in FIG. 2a, can determine the transmission direction of the transmission path jointly by the tangential end 2, and the transmission direction can be from the top of the hierarchical structure toward the bottom (Bottom) or from the bottom toward the top ( As shown in the figure in Figure 4).

On the other hand, if the hierarchical architecture is not formed, as shown in FIG. 2b, the initiator can find a mid-point A in the transmission path, for example, calculate a midpoint from the channel distance between the sharing terminals 1 As the middle break point A. Next, the initiator includes the plurality of tangential ends 2 including a root 2R and a plurality of leaves 2L, the root 2R being the closest to the tangential end 2 of the middle break point A, the leaf 2L To connect the tangled end 2 of each sharing end 1; or, as shown in Fig. 2c, the tangential end 2 further includes at least one branch 2B connected to the tangled end between the root 2R and the leaf 2F 2.

Then, all the tangential terminals 2 can negotiate or adjust the transmission direction of the transmission path according to the current network condition, for example, the transmission direction can be oriented from the leaf 2L toward the root 2R, or from the root 2R The leaf 2L (as shown in FIG. 4); in addition, the adjacent adjacent tangential end 2 can jointly determine the transmission direction of the transmission path between the two according to the current network condition (as shown in FIG. 5). ).

In the quantum transmission step S3, a plurality of tangled quantums (Entangled Quantum) are generated by the tangential terminal 2, so that the quantum is transmitted (or Swapping) to the sharing terminals 1 in parallel according to the transmission direction. In detail, as shown in FIG. 4, the tree root 2R can be generated according to a conventional quantum entanglement state generation method (for example, generated by a polarization photon random generator) to generate a quantum having a plurality of entangled states (ie, a plurality of quantum Tangled state), and transmitted parallel to each leaf 2L through the quantum channel, each leaf 2L generates a quantum with entangled state according to the received quantum, and transmits the generated quantum to each sharing end 1; or, can be separated by each leaf 2L Generating a quantum having an entangled state and transmitting it in parallel to the sharing end 1 and the root 2R, which is received by the root 2R The quantum produces an entangled state.

In addition, as shown in FIG. 5, if the tangential end 2 includes the branch 2B, the root 2R can also be quantum parallel transmitted to the branch 2B, so that the branch 2B has an entangled state according to the received quantum. Quantum, and then the generated quantum is transmitted to its connected leaves 2F. The leaves 2F connected by the branches 2B generate quantum with entangled states according to the received quantum, and then transmit the generated quantum to its connected sharing end 1 Or alternatively, the branch 2B generates a quantum having an entangled state, and is transmitted in parallel to the connected leaf 2F and the root 2R, and the received root generates an entangled state by the root 2R, and is connected by the branch 2B The leaf 2L produces a quantum with entangled states based on the received quantum, and then transmits the generated quantum to its connected sharing end 1.

Wherein, the tangled end 2 causes the quantum to generate an entangled state, and the two quantum can be subjected to Bell measurement, or the plurality of (ie, at least two) quantum can be subjected to GHZ measurement (GHZ Measurement). Or GHZ like Measurement, as exemplified below.

For example, as shown in FIG. 4, only two sharing terminals 1 want to share the same set of quantum entangled states, and the quantum number received by any tangential end 2 (for example, 2L1) by other tangential terminals 2 is j. (j>0), and if the quantum quantity to be transmitted to the sharing end 1 or other tangled end 2 is i(i≧0), then it is judged whether i is 0 or not, and if "i=0", it can be received. The j quantum to the GHZ measurement or the GHZ like measurement is performed as shown in the following formula (1): Where |Ψ> is one of the m GHZ states or one of the m GHZ like states, k {0,1}, It is the Tensor Product.

On the other hand, if "i≧1", you can choose to generate (i+j) quantum with entangled states, as shown in the following equation (2): Where |Ψ> is the entangled state of quantum, For the tensor product. Thereafter, i (i+j) of the quantum having the entangled state are transmitted to the sharing terminal 1 or other tangential terminal 2, and the (j+j)th remaining j of the quantum having the entangled state are received. The j quantum measurements of the two quantum measurements are performed, so that the j-group quantum entangled states form one of four Bell states, which are represented by the following formulas (3a), (3b), (3c) or (3d). Show:

Where |Φ ⁺ 〉, |Φ ^- 〉, |Ψ ⁺ 〉 and |Ψ ^- 〉 are respectively one of four kinds of Bell states, |00>, |11>, |01> and |10> are two orders Different combinations of photons (eg: |0> or |1>).

In addition, it is also possible to generate (i+1) quantum with entangled states, as shown in the following equation (4): Where |Ψ> is the entangled state of quantum, For the tensor product. The i quantum with the entangled state will be transmitted to the sharing end 1 or other tangential end 2, and the remaining quantum with the tangled state will perform a GHZ measurement or a GHZ like measurement with the received j quantum. The j+1 quantum is formed into one of m species GHZ state or GHZ like state, as shown in the above formula (1).

As another example, as shown in FIG. 5, there are two or more (for example, three) sharing terminals 1 to share the same set of quantum entangled states, since the sharing terminal 1 and the tangential end 2 form the minimum. Spanning tree M. In addition to the root 2R, the other tangled ends 2 (such as 2L and 2B shown in FIG. 5) are respectively regarded as an internal node; each internal node is connected to a parent node (may be Tree root 2R or another internal node) and x child nodes, for example, the internal node 2B connects its parent node 2R and one child node 2L, and the other internal nodes and so on; the x child nodes include another a internal node and (xa) external nodes (that is, the sharing terminal 1), for example, the one child node 2L includes another 0 internal nodes and one external node 1; each internal node receives quantum from the a internal node, and Generate (x+1) quantum with entangled states, as shown in the following equation (5): Where |Ψ> is the GHZ state or the GHZ like state, For the tensor product. Then, the (x+1) quantum of the entangled state and the quantum of the a internal node are subjected to Bell measurement, and then (xa) of the (x+1) quantum are transmitted to The outer node transmits one of the (x+1)th quantum to the parent node, wherein x and a are both positive integers and x is greater than a.

Moreover, the root 2R is connected to y child nodes, for example: 3 child nodes 2L1, 2L2, and 2B; the y child nodes include b internal nodes (that is, the other tangled ends 2 except the tree root 2R) and (yb An external node (that is, the sharing terminal 1), for example, the child nodes 2L1, 2L2, and 2B include one internal node 2L3 and two external nodes 1a, 1b; the tree root 2R receives the internal nodes from the b The quantum, and produces y quantum with entangled states, as shown in the following equation (6): Where |Ψ> is the GHZ state or the GHZ like state, For the tensor product. Then, the quantum of the y quantum entangled states and the b internal nodes are measured by Bell, and then (yb) of the y quantum are transmitted to the external node, where y b is a positive integer and y is greater than b.

In addition, the tangled end 2 is required to transmit the quantum front, and may also be based on the noise type of the transmission channel (ie, the quantum channel), for example, a collective-dephasing noise or a collective-rotation noise. ), and choose to be able to transmit the entangled state of the noise, for example, if the single photons are tensor productized with each other, the phase decay can be countered by |0> ₁ |1〉 ₂ and |1〉 ₁ |0〉 ₂ Noise; if two quantums are measured by Bell, then |Φ ⁺ 〉 and |Ψ ^- 〉 can be used to combat phase rotation noise; the remaining tangled states against noise are understood by those of ordinary skill in the art to which the present invention pertains. I will not repeat them here.

Furthermore, the quantum transmission process may also employ a wiretapping verification mechanism, for example, by a transmitter (eg, the tangled end 2) from |0>, |1>, |+> and |->Selecting the induced photons (decoy photon) from the four single photons, and then randomly inserting the induced photons into a photon of the transmitted message, and then transmitting the transmitted message, the position, base and value of the induced photon to a receiver Used to detect eavesdroppers. Wherein, since the eavesdropper does not know the position, the base and the value of the induced photon, if the eavesdropper evades the eavesdropping (or attacking) the transmitted message, the state of the induced photon may be changed, and therefore, when the recipient (for example, the sharing end) 1) After receiving the transmission message, the induced photon can be taken out according to the correct position, and the induced photon is measured with the correct substrate. If the measurement result is different from the value published by the transmitter, it indicates that an eavesdropper exists. However, it is not limited thereto, and it can be understood by those having ordinary knowledge in the field to which the present invention pertains, and is not described herein.

In addition, the quantum transmission process may also use a quantum error correction code, for example, using an error correction code such as a Hamming Code, and changing the encoded logical values 〝0〞 and 〝1〞 to corresponding single photons| 0> and |1>, so that single photon|0> and |1> can represent two different logical values, but not limited thereto, which can be understood by those having ordinary knowledge in the field to which the present invention pertains. Do not repeat them. Therefore, the quantum with the entangled state can be correctly transmitted to each sharing end 1 for the sharing end 1 to perform quantum communication and the like according to the measurement results of the tangled state of the quantum by the tangential end 2 .

According to the foregoing technical means, the quantum entangled state construction method of the present invention uses one of the plurality of sharing terminals 1 as the initiator to confirm the transmission path between the sharing terminals 1 (for example, using a routing protocol and The weighting value of each channel cost); then, the initiator confirms that the hierarchical structure is formed between the sharing end 1 and the tangled end 2, and then the tangential end 2 determines the transmission direction of the transmission path; The tangled end 2 produces an entangled state The quantum is transmitted to the sharing terminals 1 in parallel according to the transmission direction (for example, the uplink or downlink direction).

Therefore, if there is no traditional channel and quantum channel between any of the sharing end 1 and the tangential end 2 (as in the case of the actual fiber optic network), it can also pass through the other tangential end 2 and the conventional channel and quantum channel connected therebetween. The quantum is effectively transmitted to the sharing terminal 1, so that the sharing terminals 1 can effectively and safely share the same set of quantum entangled states for use as quantum communication and the like. Moreover, in the case that all the transmission nodes do not need to establish channels in two or two, the channel construction and maintenance costs can be reduced, and the economic benefit in use is improved, which is the effect of the invention.

Furthermore, each of the tangled ends 2 is parallelized to process quantum entanglement states such as quantum generation, entanglement, and transmission operations, and the quantum entanglement state can be reduced by performing the above-described quantum entanglement state construction operation in a conventional manner. Setting the operating time to provide a highly efficient quantum network environment is an effect of the present invention.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

〔this invention〕

1,1a, 1b‧‧‧Shared

2‧‧‧ tangled end

2B‧‧‧ branches

2L‧‧‧ leaves

2L1, 2L2, 2L3‧‧‧ leaves

2R‧‧‧ Tree Roots

A‧‧‧ 中折点

M‧‧‧Minimum Spanning Tree

T‧‧‧Traditional channel

Q‧‧‧Quantum channel

S1‧‧‧ Path establishment steps

S2‧‧‧ class establishment steps

S3‧‧‧Quantum transfer steps

[study]

C1, C2, Cn‧‧‧ client

E1‧‧‧ source

E2‧‧‧ destination

R1, Rn‧‧‧ relay

V, V1, Vn‧‧‧ server

q,q’‧‧· quantum

Q0, q0’‧‧‧ quantum

Q1, q1’‧‧‧ quantum

Q1, q2‧‧‧ quantum

Qn, qn’‧‧‧ quantum

Figure 1a: Schematic diagram of the first conventional quantum entanglement state construction method.

Figure 1b: Schematic diagram of the second conventional quantum entanglement state construction method Figure.

Figure 1c: Schematic diagram of the structure of the third conventional quantum entanglement state construction method.

Figure 2a is a schematic diagram of the architecture of the preferred embodiment of the quantum entanglement state construction method of the present invention (1).

Figure 2b is a schematic diagram of the architecture of the preferred embodiment of the quantum entanglement state construction method of the present invention (2).

Figure 2c: Schematic diagram of the architecture of the preferred embodiment of the quantum entanglement state construction method of the present invention (3).

Figure 3 is a flow chart showing the operation of the preferred embodiment of the quantum entanglement state construction method of the present invention.

Fig. 4 is a schematic view showing the transmission direction of the preferred embodiment of the quantum entangled state construction method of the present invention (1).

Fig. 5 is a schematic view showing the transmission direction of the preferred embodiment of the quantum entangled state construction method of the present invention (2).

S1. . . Path establishment step

S2. . . Hierarchy establishment step

S3. . . Quantum transmission step

Claims (27)

A quantum entangled state construction method is applied to a network environment, comprising: a path establishment step, wherein one of a plurality of sharing ends is used as an initiator, and the initiator uses a routing protocol to find a transmission path between each sharing end The transmission path is connected to the sharing end and the plurality of tangled ends, and the sharing end, the tangling end and the combination thereof are coupled to each other by a traditional channel and a quantum channel, and the initiator is weighted according to the routing protocol and the channel cost. Searching for the best path between the sharing end and the tangled end to form a minimum spanning tree and finding the longest path in the minimum spanning tree as the transmission path; a hierarchical establishment step is performed by the initiator The sharing end, the connection relationship between the tangled end and the transmission path confirms that the sharing end and the tangled end form a hierarchical structure, and then the tangled end negotiates to determine the transmission direction of the transmission path; and a quantum transmission step A plurality of quantumes having entangled states are generated by the tangential end, so that the quantum is transmitted in parallel to each sharing end according to the transmission direction. The method for constructing a quantum entanglement state according to claim 1, wherein the hierarchical establishment step is performed by the initiator in the transmission path to find a mid-point, and the tangled end is one of the closest to the intermediate point. At the top of the hierarchical architecture, the share is the bottom of the hierarchical architecture. The method for constructing a quantum entanglement state according to claim 1, wherein the hierarchical establishment step is that the initiator searches for a mid-point in the transmission path, wherein the plurality of tangential ends comprise a root and a plurality of Leaves, the root of which is closest to one of the tangential ends of the mid-point, the leaves are connected The tangled end of the sharing end. The method for constructing a quantum entanglement state according to the second or third aspect of the patent application, wherein the initiator calculates a distance midpoint as the middle vertices by using a channel distance between the sharing ends. The method for constructing a quantum entanglement state according to claim 3, wherein the quantum transmission step generates a quantum having an entangled state from the root of the tree, and transmits it to each leaf in parallel, and each leaf has a quantum generated according to the received The quantum of the entangled state, and the generated quantum is transmitted to each sharing end. The method of constructing a quantum entanglement state according to claim 5, wherein the tangential end comprises at least one branch connected to a tangled end between the root of the tree and the leaf, the branch being based on the received quantum Generating a quantum with entangled states and transmitting the generated quantum to its connected leaves, the leaves connected by the branches generate quantum with entangled states according to the received quantum, and then transmit the generated quantum to its connected share end. The method for constructing a quantum entanglement state according to claim 3, wherein the quantum transmission step generates a quantum having an entangled state from each leaf, and transmits it to the sharing end and the root of the tree in parallel, from the root The received quantum produces an entangled state. The quantum entangled state construction method according to claim 7, wherein the tangential end comprises at least one branch connected to a tangled end between the root of the tree and the leaf, the branch generating an entangled state Quantum, and transmitted in parallel to its connected leaves and the root of the tree, from which the received quantum produces an entangled state, and the leaves connected by the branch produce a quantum with entangled states according to the received quantum, and then The resulting quantum is transmitted to the shared end of its connection. The method for constructing a quantum entanglement state according to claim 1, wherein the tangential end performs two-quantum measurement on the quantum, so that the quantum produces an entangled state. The method for constructing a quantum entanglement state according to claim 1, wherein when any entangled end receives j(j>0) quantum and needs to transmit i(i≧1) quantum, then ( i+j) A quantum with entangled states, as shown in the following equation: Where |Ψ> is the entangled state of quantum, For the tensor product; i of the above (i+j) quantums are transmitted to the sharing end or other tangled ends, and the remaining j of the above (i+j) quantums are compared with the received j quantum twos. Measure. The method for constructing a quantum entanglement state according to claim 9 or claim 10, wherein when two quantums are subjected to Bell measurement, the entangled state of the quantum is as follows: Where |Φ ⁺ 〉 is one of the four Bell states. The method for constructing a quantum entanglement state according to claim 9 or claim 10, wherein when two quantums are subjected to Bell measurement, the entangled state of the quantum is as follows: Where |Φ ^- 〉 is one of the four Bell states. The method for constructing a quantum entanglement state according to claim 9 or claim 10, wherein when two quantums are subjected to Bell measurement, the entangled state of the quantum is as follows: Among them, |Ψ ⁺ 〉 is one of the four Bell states. The method for constructing a quantum entanglement state according to claim 9 or claim 10, wherein when two quantums are subjected to Bell measurement, the entangled state of the quantum is as follows: Among them, |Ψ ^- 〉 is one of the four Bell states. The method for constructing a quantum entanglement state according to claim 1, wherein the tangled end performs GHZ measurement or GHZ like measurement on the plurality of quantum, so that the quantum generates an entangled state. The method for constructing a quantum entanglement state according to claim 1, wherein when the tangential end receives j(j>0) quantum and needs to transmit i(i≧0) quantum, if i=0 Then, the received j quantum is subjected to a GHZ measurement or a GHZ like measurement. If i≧1, (i+1) quantum with entangled state is generated, wherein i quantum is transmitted to the sharing end or other At the tangled end 2, the remaining 1 quantum and the received j quantum are subjected to a GHZ measurement or a GHZ like measurement. The quantum entangled state construction method according to claim 15 or 16, wherein when the quantum is subjected to GHZ measurement or GHZ like measurement, the entangled state of the quantum is as follows: Where |Ψ> is one of the m GHZ states or one of the m GHZ like states, k {0,1}, For the tensor product. The quantum entangled state construction method according to claim 6, wherein the other tangled ends are respectively an internal node, and each internal node is connected to one parent node and x child nodes, and the x children are connected to the tree root. The node includes another a internal node and (xa) external nodes, after each internal node receives the quantum from the a internal node, and generates (x+1) quantum with the entangled state, the (x+ 1) a quasi-quantized quantum of which a and the a internal node are subjected to Bell measurement, and then (xa) of the (x+1)th quantum are transmitted to the external node, and the One of the (x+1)th quantum is passed to the parent node, where x and a are both positive integers and x is greater than a. The method for constructing a quantum entanglement state according to claim 18, wherein the parent node is the root of the tree or another internal node, and the external node is the sharing end. The method for constructing a quantum entanglement state according to claim 18, wherein the entangled state of the (x+1) quantum is as follows: Where |Ψ> is the GHZ state or the GHZ like state, For the tensor product. The method for constructing a quantum entanglement state according to claim 3, wherein the tree root is connected to y child nodes, and the y child nodes include b internal nodes and (yb) external nodes, and the root of the tree is received from the root node. The quantum of b internal nodes, and after generating y quantum with entangled states, the b of the y quantum with entangled states and the b internal nodes The quantum is measured by Bell, and then (y-b) of the y quantum is transmitted to the external node, wherein y and b are both positive integers, and y is greater than b. The method for constructing a quantum entanglement state according to claim 21, wherein the internal node is a tangled end other than the root of the tree, and the external node is the sharing end. The method for constructing a quantum entanglement state according to claim 21, wherein the entangled state of the y quantum is as follows: Where |Ψ> is the GHZ state or the GHZ like state, For the tensor product. The method for constructing a quantum entanglement state according to claim 1, wherein the tangled end selects an entangled state capable of transmitting noise against the noise according to the type of noise in the quantum transmission, wherein the noise category is Phase decay noise or phase rotation noise. The method for constructing a quantum entanglement state according to claim 1, wherein the sharing end performs quantum communication according to the measurement result of the entangled state of the quantum according to each tangential end. The method for constructing a quantum entanglement state according to claim 1, wherein the transmission process of the quantum uses a wiretapping test mechanism, and a transmitter transmits from |0>, |1>, |+>, and |-> The induced photon is selected from the single photon. After the induced photon is randomly inserted into the quantum, the quantum, the position, the base and the value of the induced photon are transmitted to a receiver. The method for constructing a quantum entanglement state according to claim 1, wherein the quantum transmission process uses a quantum error correction code and is a single photon. |0> and |1> represent two distinct logical values.