37 results about "Bell state" patented technology

The invention relates to the technical field of quantum information, and discloses a method for controllably and remotely executing any target quantum operation of a single quantum bit, and the method comprises the steps: employing a one-dimensional five-quantum-bit cluster state as an entanglement resource, and forming a quantum information transmission channel through the reasonable configuration of quantum bits; quantum bit measurement and classical information transmission are executed by an information control party, and generation of a channel access authorization key and secure transmission of a target quantum state are realized; the operation executor executes a series of quantum operations and Bell state measurement according to the received classic information and transmits a measurement result to the receiving agent; and the receiving agent executes a dynamic conversion operation according to the received classical information and the channel access authorization key, and finally controlled remote execution of the target quantum operation is realized. According to the method and the device, the confidential quantum information is quickly and safely transmitted under the condition that the operation executor does not completely trust the receiving member.

Methods and systems are provided for performing an encoded n-qubit GHZ measurement on n encoded (logical) qubits using encoded Bell state measurements (E-BSMs). Each E-BSM comprises a plurality of dual-rail Bell state measurements (DR-BSMs) performed on pairs of dual-rail encoded photonic qubits (DR-qubits). Methods and systems for using encoded n-qubit GHZ measurements for fault-tolerant measurement-based quantum computation are also provided.

This paper proposes a single-state multi-party semi-quantum secret sharing method based on d-dimensional Bell states, which achieves the goal of "the sender's key can only be recovered when all receivers work together." This method has been proven to be resistant to both external and participant attacks. The method is applicable to d-dimensional quantum systems, uses only a single d-dimensional Bell state as the initial quantum resource, and requires neither quantum entanglement exchange nor unitary operations.

The application discloses a kind of machine room equipment intelligent remote operation and maintenance method and platform, it is related to intelligent operation and maintenance technical field, including, construct bayesian probability model, and combine optical signal characteristics and current harmonic characteristics, predict the failure probability distribution of machine room equipment;According to the failure probability distribution of machine room equipment, convert fault coordinates into equipment logical identifier, and detect the quantum teleportation link of machine room equipment, generate machine room equipment switching instruction according to detection result;According to machine room equipment switching instruction, send Bell state measurement command to fault equipment, and carry out quantum state reconstruction and machine room equipment switching.The application constructs multilayer bayesian probability model based on Gaussian distribution, Granger causality test and variational inference, realizes the nonlinear correlation analysis of optical signal wavelength shift and current harmonic characteristics, can accurately capture the weak signs of potential equipment failure, to significantly improve the sensitivity and reliability of failure prediction.

The invention relates to quantum key distribution, in particular to a quantum key distribution system and method of a single copy QPA based on hyper-entanglement, a hyper-entanglement photon pair source synchronously generates a hyper-entanglement photon pair which is in a maximum entanglement Bell state at a polarization degree of freedom and an energy-time degree of freedom; the QPA processing module is positioned in the transmitting end Alice and the receiving end Bob, and is used for projecting energy-time high-dimensional entanglement to a path degree of freedom and realizing deterministic CNOT gate operation between different degrees of freedom in a single photon; the detection and post-processing module is located in the transmitting end Alice and the receiving end Bob, selects coincidence events with consistent detection results, and generates a final security key by using a distilled entangled state with higher fidelity on the degree of freedom of polarization; according to the technical scheme provided by the invention, the defect that reliable quantum key distribution is difficult to realize in a complex channel environment in the prior art can be effectively overcome.

The invention relates to a novel quantum secret sharing method based on a Bell state. The method comprises the following steps that: firstly, a secret distributor sends a sequence of mixed Bell states and decoy particles to participants; secondly, the participants encode secret shares of the participants into corresponding Pauli operators, and the Pauli operators are applied to the received particle sequences; and finally, the participants recover the shared secret information through cooperation. And shared secret information can be obtained by executing Bell-based measurement by a secret distributor. Compared with other quantum secret sharing methods, the method has the advantages that the secret distributor does not grasp the secret share of the participant, even if the secret distributor grasp the shared secret information, the secret share of the participant cannot be deduced, and the privacy and benefits of the participant can be effectively protected. On the basis of meeting safety, a Bell state is used as a quantum carrier, and compared with an entangled state of n particles, the Bell state is easier to prepare; and meanwhile, various eavesdropping attacks can be effectively resisted. Compared with a traditional method, the method is more practical and higher in efficiency.

This invention belongs to the field of quantum dialogue and discloses a one-step quantum dialogue method. In this method, communicator A prepares a large number of identical polarization-spatial hyperentangled states and sends one photon from each hyperentangled state to communicator B through a quantum channel, establishing a hyperentangled quantum channel between the two parties. After confirming the security of the photon transmission process, both parties encode the photon pairs according to the information to be transmitted. Then, by running nonlocal Bell state measurements and publishing the detector responses, both parties can read the information transmitted by the other, thus achieving bidirectional quantum communication, i.e., quantum dialogue. Compared with existing quantum dialogue protocols, this invention reduces the number of photon transmissions in the channel from two to one, simplifying experimental operations and effectively reducing the photon loss rate, which can effectively promote the practical application of quantum dialogue.

The invention discloses a controlled semi-quantum dialogue method and system based on semi-quantum cryptography and an entangled Bell state. Wherein a manager Charlie prepares a large number of entangled photon pairs, and splits the photon pair in each entangled state into a coding sequence and a test sequence. Only under the condition that the channel is ensured to be safe, the quantum communication party Alice and the classic communication party Bob can code in the sequence in sequence, and finally the code is returned to the management party Charlie for measurement to complete communication. According to the method, the quantum communication party and the classical communication party can exchange secret information at the same time under the supervision of the management party Charlie, that is, only through the permission of the management party Charlie. In addition, compared with a one-way semi-quantum communication protocol, the communication efficiency is remarkably improved by introducing a dialogue mechanism. Compared with a complex GHZ state, the Bell state adopted by the invention is simpler and more convenient in preparation, so that the implementation difficulty is reduced.

Disclosed is a quantum diagnostic circuit, which includes an input unit having an input of at least first to fourth qubits, a diagnostic circuit unit receiving the first to fourth qubits from the input unit and providing a quantum superposition and a quantum entanglement, and an output unit receiving an output of the diagnostic circuit unit and determining whether the output is in a Bell-state, and the diagnostic circuit unit includes a Hadamard gate processing the first qubit to provide the quantum superposition of the first to fourth qubits, a first CNOT gate providing the quantum entanglement between an output of the Hadamard gate and the second qubit, a second CNOT gate providing the quantum entanglement between an output of the first CNOT gate and the third qubit, and a third CNOT gate providing the quantum entanglement between an output of the second CNOT gate and the fourth qubit.

Aspects of the present disclosure relate generally to systems and methods for use in the implementation and / or operation of quantum information processing (QIP) systems, and more particularly, to ion entanglement. Some examples include generating a fused resource-state between atomic qubits of non-neighboring parcels such that the atomic qubit share a Bell state.

This invention discloses a method and system for implementing a completely reference-frame-independent quantum key distribution protocol, belonging to the field of quantum information technology. Alice and Bob, the communicating parties, randomly select mutually unbiased basis vectors to prepare quantum states and send them to a third party, Charlie. Charlie performs Bell state projection measurements and announces the success. Both parties publish the basis vector information, divide the dataset, and calculate the gain and bit error rate. A 3×3 correlation tensor matrix is ​​constructed and singular value decomposition is performed to obtain three reference-frame-independent singular values. The secure key rate is calculated based on the bit error rate. Finally, key negotiation and security enhancement are performed to extract the secure key. This invention does not require basis vector alignment, completely eliminating the dependence on reference frame calibration. It can still stably generate keys even with basis vector drift, and the amount of information required by eavesdroppers is lower, significantly improving the practicality and security of the quantum key distribution system.

The present application provides a method of entanglement swapping in a quantum information network (1) comprising a plurality of nodes including a first and a second endpoint (11a, 11e) and a sequence of intermediary nodes (11b, 11c, 11d) linking the first and the second endpoint. The claimed method comprises repeated entanglement swapping mediated by a BSM-based LOCC between two adjacent elementary links. Upon confirming that all Bell-state measurements are successful, a combined quantum state postprocessing is performed that is conditional on a result of a combined Boolean logic operation. The present application further pertains to a corresponding quantum information network and to an intermediary node for the network.

The invention relates to the technical field of quantum security calculation, and discloses a multi-party multi-data summation method based on a d-dimensional cluster state, which introduces a semi-honest third party to assist in completing summation calculation, and constructs a bidirectional identity authentication process between a participant and the third party by using a dual one-way hash function, thereby effectively preventing identity impersonation attack. In a multi-party multi-data summation stage, a multi-party quantum information interaction structure is established by using quantum entanglement association between a d-dimensional Bell state and a d-dimensional cluster state, and secure coding and aggregation of private data of participants are realized through Bell measurement. Meanwhile, detection particles from (d + 1) groups of complementary bases are randomly inserted into a quantum channel and are used for detecting potential eavesdropping behaviors and ensuring the safety of a quantum communication process.

The application discloses a high-quality quantum network construction method based on self-detection technology and relates to the field of quantum communication, which comprises the following steps: entanglement measurement is performed by using an intermediate node, so that a center node and a plurality of edge nodes share a preset number of pairs of Bell states; the center node and each edge node jointly select half of the Bell states to perform Bell state self-detection, and if the Bell state self-detection is passed, the remaining Bell states are reserved and grouped; half of the groups of shared quantum states are selected to perform generalized GHZ state measurement self-detection, and if the generalized GHZ state measurement self-detection is passed, the center node performs generalized GHZ state measurement on the remaining groups, so that the plurality of edge nodes share high-quality generalized GHZ states. The two-stage device-independent self-detection mechanism is used to screen quantum resources and measurement operations, the quality instability problem caused by noise and loss accumulation in the traditional method is overcome, and it is ensured that the final distributed entangled states have very high fidelity, thereby providing reliable guarantee for subsequent quantum tasks.

The present invention belongs to the field of quantum communication technology and discloses a measurement device-independent quantum dialogue method based on entanglement exchange, in which user B first loads the information to be transmitted into an entangled photon pair through phase encoding. Users A and B establish a long-distance entangled channel through two Bell state measurements at one end of the detection party. User A then performs phase encoding to load the information to be transmitted into its own photon. Both parties then send the photons in their hands to the detection party for a third Bell state measurement. Based on the results of the three Bell state measurements and their respective operations, the two parties can decode the information transmitted by the other party and complete the dialogue. The present invention can effectively resist all attacks from the measurement end and ensure the security of quantum dialogue under the actual conditions of imperfect detection equipment. The present invention uses all linear optical devices, which can be implemented under current experimental conditions and can effectively promote the practical application of MDI-QD.

The invention discloses a non-interactive multi-party dynamic quantum homomorphic encryption method and a non-interactive multi-party dynamic quantum homomorphic encryption device, which can simultaneously ensure that a dynamic processing server is unstable and the problem of errors during T gate homomorphic evaluation is solved in a non-interactive manner, and can be expanded into a multi-client multi-server mode. The method comprises the following steps: (1) generating a Bell state and carrying out secret segmentation; (2) generating an encryption key set; (3) encrypting the corresponding particle set by using the encryption key; (4) evaluating; and (5) decrypting the ciphertext by using the decryption key.

The invention discloses a Bell state and rotation operation-based practical quantum privacy comparison protocol method, which comprises the following steps that: a semi-honest third party prepares S and records the state of the S, and first particles and second particles in all Bell states are respectively utilized to form S1 and S2; first eavesdropping detection is carried out, if the first eavesdropping detection passes, the first participant and the second participant respectively obtain S1 and S2, and the next step is continued, otherwise, communication is stopped; the first participant and the second participant act rotation operations Ry (piX) and Ry (piY) on the S1 and the S2 respectively to obtain SA and SB and send the SA and the SB to the semi-honest third party; the semi-honest third party sequentially executes Bell-based measurement on the SA and the SB to obtain a measurement result, if the measurement result is consistent with the quantum sequence S, the semi-honest third party declares that the privacy information of the first participant and the privacy information of the second participant are the same, otherwise, the privacy information of the first participant and the privacy information of the second participant are different. According to the method, possible information leakage is effectively prevented, the capability of resisting external and internal attacks of the method provided by the invention is remarkably enhanced, and the technical threshold and the cost of implementation are greatly reduced.

An apparatus for providing Bell fusion comprises a measurement unit configured to apply a Bell fusion operator to a plurality of Bell blocks 10-1, 10-n corresponding to pairs of photons 1-m in a quantum entanglement state to sequentially measure a zeroth level 10 of a Bell state for each of the plurality of Bell blocks; a selection unit configured to select a Bell fusion operator to be applied to a next Bell block of the plurality of Bell blocks based on a result of measuring a zeroth level of Bell state for a previous Bell block corresponding to the next Bell block; and an identification unit configured to identify a first level of Bell state for a Bell box 20 including the plurality of Bell blocks based on a result of measuring a zeroth level of Bell state for each of the plurality of Bell blocks. A second level for a Bell network is also identified. Bell fusion is achieved using linear optics. Quantum error correction is achieved through a hierarchical Bell state measurement in a feed-forward method increasing the success probability of fusion. Limiting the number of failure for the Bell state measurement improves the limitation of photon losses.

This invention discloses a highly practically secure continuous-variable quantum secret sharing method, belonging to the field of quantum communication technology. Specifically, the method involves: First, establishing a communication scenario consisting of an untrusted measuring party, a distributor, and n participants; the n participants and the distributor prepare their respective quantum states and transmit them to the measuring party through a quantum channel; the measuring party performs Bell state measurements on the quantum states from the participants and the distributor and publishes the measurement results; then, the distributor and participants each randomly select a portion of the quantum state data and, combined with the publicly published measurement results from the measuring party, calculate the transmittance of all channels. Next, the distributor performs classical post-processing with each participant sequentially to obtain their respective keys; finally, the participants and the distributor verify the keys using a hash function. This invention, by having an untrusted third party perform quantum state measurements and publish the results, avoids security vulnerabilities caused by detector non-ideals.

This invention discloses a controllable authentication quantum dialogue method based on Bell states, where a third-party quantum dialogue controller C, quantum communicator A, and quantum communicator B share identity authentication information pairwise. The third-party quantum dialogue controller C prepares a Bell state sequence and two Bell state sequences for identity verification. Then, it splits the Bell state sequence into single-particle sequences, sending a portion of the particle sequence to quantum communicator A and quantum communicator B respectively. The third-party quantum dialogue controller C verifies the identity information of quantum communicator A and quantum communicator B, and quantum communicator A and quantum communicator B verify each other's identity information. Quantum communicator A and quantum communicator B each perform unitary operations on the communication particles with the message to be sent. Based on the measurement results of the Bell states after the Bell unitary operations, quantum communicator A and quantum communicator B deduce the message sent by the other party. This method achieves bidirectional secure and efficient communication between quantum communicator A and quantum communicator B under the control of a semi-trusted third-party quantum dialogue controller C, while simultaneously solving the three-party identity authentication problem. The method of this invention is simple and easy to implement, with good practical feasibility.

This invention discloses a controlled semi-quantum dialogue method and system based on Grover's quantum search algorithm. Two classical users entrust a manager, Charlie, to perform quantum searches, thereby achieving bidirectional secure communication. First, Bell states are used to enable the classical user to obtain a shared string, which is then used to encrypt the identifier string. Subsequently, Charlie, based on the search request command, applies Grover's algorithm to sequentially execute the phase flip operator and the diffusion operator, iterating this process times. Finally, Z-basis measurements are used to obtain the target information. This allows classical users to entrust the quantum search algorithm, which they cannot execute independently, to Charlie. Furthermore, the two classical users can only exchange secret information with Charlie's authorization. By introducing Grover's quantum search algorithm mechanism, a quadratic speedup in computational efficiency is achieved.

The present invention provides a method for sharing maximum entangled states in an amplitude-damped channel based on coherence compensation, which relates to the field of quantum communication. Specifically, the distributor Alice prepares a maximum entangled Bell state based on single-particle A and single-particle T, and sends single-particle T to the receiver Bob via an amplitude-damped channel; the receiver Bob performs a quantum controlled NOT gate operation on the prepared single-particle B and the received single-particle T, and then sends single-particle T to the distributor Alice via an amplitude-damped channel; the distributor Alice performs a joint unitary operation on single-particle A and single-particle T, and then performs a single-particle Z-basis measurement on single-particle T, thereby achieving maximum entangled Bell state sharing between two parties in the amplitude-damped channel. This method is also applicable to maximum entangled GHZ state sharing between multiple parties in an amplitude-damped channel. The present invention adopts a coherence compensation mechanism to effectively suppress amplitude damping noise, thereby improving the fidelity of quantum teleportation and multi-party quantum state sharing.

In some aspects, the techniques described herein relate to a method including: providing, from a first endpoint, an unentangled photon containing image information to an intermediate server via a first multimode fiber; generating, at a second endpoint, an entangled photon pair including a first entangled photon and a second entangled photon; providing, from the second endpoint, the first entangled photon to the intermediate server via a second multimode fiber; Bell state measuring the unentangled photon and the first entangled photon at the intermediate server to swap entanglement of the first entangled photon such that the unentangled photon becomes entangled with the second entangled photon; providing, from the intermediate server to the second endpoint, results of the Bell state measuring; and generating an image corresponding to the image information at the second endpoint using the second entangled photon and the results of the Bell state measuring.

A distributed quantum computing system 100, e.g. a quantum memory, comprises: quantum computing units 102 of qubits; quantum networking units 104, each coupled to qubits on the quantum computing units and being configured to selectively couple each qubit to a fixed number of outputs; entanglement units 106, each having inputs to receive signals from the quantum networking units 104 and configured to entangle the received signals; a fixed coupling network 110 comprising predefined network pathways between outputs of the quantum networking units and the inputs of the entanglement units; and a control system 108 configured to control the plurality of the quantum networking units 104 to entangle qubits of the quantum computing units according to a topology associated with an error correcting code. The networking units 104 comprise photonic integrated chips to selectively couple each qubit to the fixed number of outputs. Network pathways may comprise optical fibers. The topology may be divided into tiles with connections such that the number of connections between tiles is minimised. Entanglement units 106 comprise performing Bell state measurements. The error-correcting code may be: low-density parity-check, qLDPC; hyperbolic or semi-hyperbolic; Floquet. [figure 1]

The application provides a novel arbitration quantum signature method based on Bell states, which is used for improving the security performance of AQS; the steps are as follows: firstly, a specific Bell state is encoded by the hash function output value of a message; secondly, the signature sender, the signature receiver and the arbitration management party exchange the encoded Bell state sequence in a specific way; the signature sender and the signature receiver respectively encrypt the measured results of the exchanged Bell state by using different keys, and send the ciphertext to the arbitration management party; finally, the arbitration management party verifies the signature legality by searching a specific table. The application performs digital signature based on Bell quantum states, BB84 protocol and quantum one-time encryption and decryption algorithm, and has formal security proof.

An apparatus for providing Bell fusion comprises a measurement unit configured to apply a Bell fusion operator to a plurality of Bell blocks corresponding to pairs of photons in a quantum entanglement state to sequentially measure a zeroth level of a Bell state for each of the plurality of Bell blocks; a selection unit configured to select a Bell fusion operator to be applied to a next Bell block of the plurality of Bell blocks based on a result of measuring a zeroth level of Bell state for a previous Bell block corresponding to the next Bell block; and an identification unit configured to identify a first level of Bell state for a Bell box including the plurality of Bell blocks based on a result of measuring a zeroth level of Bell state for each of the plurality of Bell blocks.

The application discloses a kind of measurement equipment independent quantum conversation methods with bidirectional identity authentication function, the method is mutually authenticated whether communication two sides are legal collaborators, then directly utilize quantum channel to mutually converse each other.Communication two sides Alice and Bob mutually share a set of identity keys by BB84 protocol, Alice and Bob are only responsible for preparing entangled photon pair and single photon, and performing encoding operation to photon, all measurement tasks are completed by third party measurement end Charlie.Alice and Bob can verify the identity of two sides according to the Bell state analysis result of Charlie, determine as the legal party of communication, and complete bidirectional communication after that.The application first applies bidirectional identity authentication technology to MDI-QD field, can resist the impersonation attack of eavesdropper, and by completing measurement task by third party, can effectively resist all attacks to imperfect measurement equipment, enhance the security of two-way identity authentication code and communication.The application has very important significance to promote the practical application of quantum conversation.

A controlled quantum secure direct communication method based on multiple groups of Bell bases comprises the following steps: a third party prepares a series of entangled photon pairs to form two photon sequences, and the two photon sequences are respectively sent to two communication parties; and the two communication parties select photons on the photon sequence for two rounds of safety detection. And the third party publishes a preparation base of the entangled photon pair, and an information receiver performs Bell state measurement and records a result according to the preparation base. An information sender publishes random coding positions and coding information, a third party publishes initial states on the positions, a receiver performs second round of security detection, and it is indicated that the channel is free of eavesdropping when the bit error rate is lower than a threshold value. And finally, the third party publishes the initial states of other positions, and the receiver deduces the information to be transmitted by the sender according to the Bell state measurement result. According to the method, only the Bell state needs to be used for communication, and only two rounds of transmission and two rounds of security detection are needed, so that the implementation complexity of a protocol can be reduced, and the communication efficiency is improved.

The invention discloses a data transmission method, device and system based on quantum communication and electronic equipment, and the method comprises the steps that a first communication node obtains a channel quality index, a quantum entanglement resource and a classic channel resource of a quantum channel in response to receiving a first entanglement state particle; determining scheduling configuration of data transmission according to the channel quality index, the quantum entanglement resource and the classic channel resource; based on the scheduling configuration, performing Bell state measurement on a quantum state corresponding to data to be transmitted and the first entangled state particles, and determining a measurement result; and the measurement result is sent to a second communication node, so that the second communication node corrects a second entangled state particle based on the measurement result, a quantum state corresponding to the to-be-transmitted data is determined, and the first entangled state particle and the second entangled state particle are mutually entangled particle pairs.

This invention discloses a method and system for measuring single-photon orbital angular momentum Bell states based on a diffractive optical neural network. Based on time-energy correlated photon pairs generated by a spontaneous parametric downconversion process, an interference light field is generated by passing a signal photon modulated into a single-photon orbital angular momentum Bell state through a Bell state evolution system. A diffractive optical processor is constructed using a diffractive optical neural network to map the interference light fields of different Bell states into Gaussian spots in different detection regions within the output plane. Fast and high-precision identification of single-photon orbital angular momentum Bell states is achieved by correlating the imaging results with an enhanced charge-coupled device (CCD) camera. The proposed Bell state measurement method possesses a signal-to-noise ratio and anti-interference capability exceeding the classical limit, maintaining high-precision Bell state identification capability even under high background noise. It exhibits low energy consumption and high efficiency, meeting the needs of green computing and sustainable development. It can be applied to quantum state measurement in the field of quantum information processing.