69 results about "Quantum memory" patented technology

A system comprising a solid state lattice containing an electronic spin coupled to a nuclear spin; an optical excitation configuration which is arranged to generate first optical radiation to excite the electronic spin to emit output optical radiation without decoupling the electronic and nuclear spins; wherein the optical excitation configuration is further arranged to generate second optical radiation of higher power than the first optical radiation to decouple the electronic spin from the nuclear spin thereby increasing coherence time of the nuclear spin; a first pulse source configured to generate radio frequency (RF) excitation pulse sequences to manipulate the nuclear spin and to dynamically decouple the nuclear spin from one or more spin impurities in the solid state lattice so as to further increase the coherence time of the nuclear spin; a second pulse source configured to generate microwave excitation pulse sequences to manipulate the electronic spin causing a change in intensity of the output optical radiation correlated with the electronic spin and with the nuclear spin via the coupling between the electronic spin and the nuclear spin; and a detector configured to detect the output optical radiation correlated with the electronic spin and the nuclear spin so as to detect a nuclear spin state of the nuclear spin.

A quantum memory includes memory cells each comprising a physical system ensemble, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, and the memory cells including two storage memory cells storing the quantum state and a transfer memory cell transferring the quantum state, only two of the memory cells being present on a straight line. The quantum memory also includes a magnet applying a magnetic field to the two storage memory cells and the transfer memory cell, a first light source irradiating the two storage memory cells and the transfer memory cell with right-handed or left-handed polarized light, a second light source simultaneously irradiating one of the two storage memory cells and the transfer memory cell with a laser beam, and a detector detecting a polarization state of the laser beam.

A memory system comprising a qubit array configured to store therein and read one or more entangled qubit states encoded using a quantum stabilizer code. The quantum-memory system further comprises a quantum-state-refresh module configured to change an entangled qubit state in the qubit array when an error is detected therein. The quantum-state-refresh module is configured to detect an error by performing a redundant measurement of a set of syndrome values corresponding to the quantum stabilizer code, with the redundant measurement being based on a block error-correction code. In one embodiment, the block error-correction code is a low-density generator-matrix code or a low-density parity-check code constructed using an EXIT-function optimization method.

A nondeterministic quantum CNOT gate (10) for photon qubits, with success probability 1 / 9, uses beamsplitters (B1–B5) with selected reflectivities to mix control and target input modes. It may be combined with an atomic quantum memory to construct a deterministic CNOT gate, with applications in quantum computing and as a Bell-state analyser.

An optical switch and optical storage loop are used as the basis of a single-photon source and a quantum memory for photonic qubits. To operate as a single-photon source, the techniques include a source of a pair of photons, such as a parametric down-conversion crystal, which is known to emit photons in pairs. The detection of one member of the pair activates the switch, which re-routes the other member into the storage loop. The stored photon is then known to be circulating in the loop, and can be switched out of the loop at a later time chosen by the user, providing a single photon for potential use in a variety of quantum information processing applications. To operate as a quantum memory for photonic qubits, a single-photon in an arbitrary initial polarization state is coherently stored in the loop, and coherently switched out of the loop when needed.

A process for constructing a superconducting Josephson-based nonvolatile quantum memory device comprising: sequentially depositing on a silicon substrate a thermal oxide buffer layer, a superconductor bottom-electrode thin film, and an oxide isolation layer; patterning an active window having dimensions smaller that 10 nanometers in the oxide isolation layer; then sequentially depositing a bottom tunnel oxide layer, a charge-trapping layer, a top cap, and a top superconductor electrode layer; defining an active region by dry etching down to the oxide isolation layer while protecting the active region from etch chemistry; depositing a device passivation layer; defining and patterning vias from a top of the device passivation layer to the superconductor bottom-electrode thin film and to the top superconductor electrode of the active region; and depositing metal interconnect into the vias.

An optical switch and optical storage loop are used as the basis of a single-photon source and a quantum memory for photonic qubits. To operate as a single-photon source, the techniques include a source of a pair of photons, such as a parametric down-conversion crystal, which is known to emit photons in pairs. The detection of one member of the pair activates the switch, which re-routes the other member into the storage loop. The stored photon is then known to be circulating in the loop, and can be switched out of the loop at a later time chosen by the user, providing a single photon for potential use in a variety of quantum information processing applications. To operate as a quantum memory for photonic qubits, a single-photon in an arbitrary initial polarization state is coherently stored in the loop, and coherently switched out of the loop when needed.

The invention provides a generating device for a continuous variable polychrome entangled optical field. The generating device for the continuous variable polychrome entangled optical field comprises a laser device, two non-degenerate optical parametric oscillation cavities and three to five unequal-arm Mach-Zehnder interference measuring systems. Due to the fact that the two cascading non-degenerate optical parametric oscillation cavities are utilized to generate the continuous variable polychrome entangled optical field, the generating device for the continuous variable polychrome entangled optical field has the advantages of being compact in structure, convenient to adjust, good in reliability and the like. The generated continuous variable polychrome entangled optical field can be applicable to both quantum memory and quantum communication and has important application values in quantum information networks.

A non-invasive method for storing, editing, deleting, appending, and retrieving infinite quantities of audio, visual or tactile data from targeted neuronal groups in the human brain. The process involves transmitting sequenced, buffered, and indexed data streams to human sensory receptors. Each data stream contains an ordinal or cardinal position that identifies a targeted group of neurons. Linear data streams may be stacked vertically and then transmitted to manufacture complete thoughts. Both linear and stacked data streams create artificial memory constructs. The manufactured memories appear older than they are because of the indexed and undated artificial mnemonic environmental variables embedded in the data stream. This method further creates a genius complex in some individuals whereby implanted memories are recalled quickly and precisely using a sequenced query that specifies the neuronal group. In stark contrast, the brain indexes naturally occurring memories with non-indexed and unknown variables randomly selected by the human senses.

The invention provides a multi-fault intelligent diagnosing method for an artificial circuit utilizing quantum Hopfield neural network and aims at multi-fault coupling of the artificial circuit. The multi-fault intelligent diagnosing method includes the steps of data acquisition, feature extraction, feature quantization, fault cause probability analysis and the like. Ideal single-fault response and actual measured multi-fault response of the artificial circuit are obtained through SPICE simulation and a data acquisition board respectively. After wavelet packet decomposition, fault response wavelet coefficient defined by a new energy function realizes construction of an energy feature space. Elements in the energy feature space is submitted on the basis of quantization to a quantum Hopfield neural network model. Neuron states and connecting weight matrix in the network are expressed in quantum states. By calculating probability value of occurrence of related weight element in measurement matrix, the occurrence probability of quantum key input mode in forms of specific quantum memory prototype at specific time, and accordingly occurrence probability of multiple faults relative to specific single fault is obtained to judge fault types.

This disclosure relates to preserving a quantum state in a quantum memory. A controller of the quantum memory determines based on a characteristic of noise that causes deterioration of the quantum state a dynamical decoupling base sequence. The duration of the base sequence is shorter than or equal to an access latency time of the quantum memory to allow access to the quantum state within the access latency time. Further, the deterioration of the quantum state is bounded to an upper deterioration limit when the base sequence is repeatedly applied to the quantum system. This provides acceptable access times while simultaneously allowing long term storage of data in the quantum state with low error rates. Repeatedly applying the base sequence to the quantum system will first yield an increasing deterioration but that deterioration will eventually reach the upper limit. As a result, over time the error rates will not exceed that upper limit and the quantum state is stable.

The invention relates to a generation device of quantum entanglement among three atomic ensembles, and mainly aims to solve the existing technical problem of probability preparation existed by quantum entanglement among a plurality of atomic ensembles. The invention adopts the technical scheme that the generation device of quantum entanglement among the three atomic ensembles comprises a light source unit, nine acousto-optic modulators, three sets of optical parametric amplifiers, a beam coupling system, the three atomic ensembles, three sets of optical filtering systems and an entanglement measurement system. Under the light writing action of quantum memory, orthogonal component quantum states of three entangled light pulses are mapped into collective spin waves of the three atomic ensembles, and quantum entanglement among the three atomic ensembles is certainly established; then, under the light reading action of quantum memory, the collective spin wave quantum states of the three atomic ensembles are mapped into the orthogonal component quantum states of the three release light pulses, and quantum entanglement among the three atomic ensemble is certainly verified through measuring correlative characteristics of the orthogonal component quantum states of the three release light pulses and the collective spin waves of the three atomic ensembles.

The invention discloses a quantum error correction code preparation method oriented to fault-tolerant blind quantum computing, which reduces the dependence of Alice preparation of error correction codes on quanta, and belongs to the technical field of quantum computing. The method comprises the following steps: S1, Alice transmitting N random weak coherent optical pulses and an auxiliary pulse sequence with a known quantum state to Bob through a quantum channel; S2, Bob preparing an unknown state required by Alice by using a random weak coherent light pulse according to a remote blind preparation quantum bit protocol, and entangling the unknown state with a quantum state in a known auxiliary pulse to create a multi-particle entangled graph in a two-dimensional plane, namely a brickwork state; and S3, Alice guiding Bob to carry out measurement-based quantum calculation on the graphic state brickwork state through the measurement angle, and preparing a required quantum error correction code. The Alice does not need a quantum memory and quantum computation, and does not need to be prepared, so that the expenditure of the Alice for the quantum aspect is greatly reduced, and the Alice is closer to a classical user.

A novel method and apparatus for long distance quantum communication in realistic, lossy photonic channels is disclosed. The method uses single emitters of light as intermediate nodes in the channel. One electronic spin and one nuclear spin coupled via the contact hyperfine interaction in each emitter, provide quantum memory and enable active error purification. It is shown that the fixed, minimal physical resources associated with these two degrees of freedom suffice to correct arbitrary errors, making our protocol robust to all realistic sources of decoherence. The method is particularly well suited for implementation using recently-developed solid-state nano-photonic devices.

The invention belongs to the technical field of communication networks, and discloses an efficient quantum privacy comparison method and system. In a quantum privacy comparison protocol, only a semi-trusted server needs to be configured with a quantum memory, a Bell-state preparation device and Bell-state joint measuring equipment; in secrete information comparison, both parties only need to configure quantum equipment for measuring and reflecting a |0>,|1> state of a quantum, so that the comparison of secrete information can be realized; in the operation process of the protocol, the semi-trusted server can be provided by a special quantum server provider, and the provider only needs to strictly comply with the requirements of the protocol, even if the provider records data in the protocolcommunication process, the provider cannot obtain the secret information of a user. The application scene of the efficient quantum privacy comparison method provided by the invention is easy to be implemented compared with an existing protocol and accords with an actual scene of a future quantum network application, and the efficient quantum privacy comparison method has a promoting effect on theapplication development of a quantum communication network.

The invention discloses a bidirectional user authentication and secret information quantum communication transmission method, and relates to the technical field of quantum communication. By adopting the method, during the secret information transmission process, the assistance of a third party is not needed, and the secret information can transmitted safely from a sending end to a receiving end through just one transmission step, thereby simplifying the information transmission process. During an eavesdropping detection process, if an information sender does not know an identity identifier IDBof an information receiver, the eavesdropping detection cannot be passed; if the information receiver does not know the identity identifier IDA of the information sender, the information receiver cannot restore the secret information, namely, the identities of the information receiver and the information sender can be authenticated in the communication process, and the secret information is transmitted more safely. According to the method, a quantum memory and a unitary operator do not need to be configured, the sending end only needs to prepare the single photon and the Bell state particles,and the receiving end only needs to measure the single photon and the Bell state particles, so that the deployment cost is reduced, and the application of a quantum communication network is promoted.

The invention discloses a post-confirmation method for a quantum sealed-bid auction. The method is characterized in that in the quantum sealed-bid auction, each bidder sends his bid price to an auctioneer, then processes and sends his bid price information to other bidders. When the auctioneer announces the winner and his bid price, other bidders can verify the authenticity of the winner based onthe previously received bid price information. The object of the invention is to solve the problems that the operation and measurement complexity of the post-confirmation method of an existing quantumsealed-bid auction protocol are high, and the existing protocol is difficult to realize without quantum entanglement resources and a quantum memory. The method enables any bidder to verify the authenticity of the final winner, ensuring the fairness of the auction.

The invention belongs to the technical field of network communication, and discloses a semi-quantum secure direct communication method and system based on a Bell state, and the method comprises the steps: a strong quantum party randomly selecting from four sets of Bell states and preparing Bell state particles, and a semi-quantum party randomly selecting measurement or reflection operation on eachparticle after receiving a sequence sent by the strong quantum party; the strong quantum party temporarily storing the particle sequence reflected by the semi-quantum party through quantum memory equipment, and informing the strong quantum party that the particles reflected by the semi-quantum party are completely received through a classical channel; and the strong quantum party measuring the remaining sequence particles to obtain a measurement result. By using the protocol provided by the invention, secret information can be directly transmitted to a common user with weak quantum capacity under relatively good efficiency transmission, so that quantum secure direct communication is completed. Based on the semi-quantum theory, the protocol can be applied to a quantum communication networkcloser to reality.

The invention provides an opto-electronic hybrid system realizing quantum coherence. The system comprises a fixed cavity mirror, a movable cavity mirror and a charge body; an optical cavity provided with cold atom cloud is formed between the fixed cavity mirror and the movable cavity mirror, and the movable cavity mirror is filled with charge; probe light is injected into the optical cavity; the charge body forms capacitive coupling with the movable cavity mirror; a current generator is electrically connected with the charge body so as to inject charge. Quantity of injected charge is regulated so as to control coulomb force between the charge body and the charge on the movable cavity mirror, then the movable cavity mirror is controlled to move relative to the fixed cavity mirror, and intensity of a cavity field generated in the optical cavity due to external action is changed, as a consequence, a quantized cavity field serving a control field is changed, then interaction between the probe light and atoms in the atom cloud is regulated coherently according to the change of the cavity field intensity, and storage / retrieval of information included in the probe light in the cold atoms or on / off of a probe light transmission path is realized. The system has the advantage of high integration of electronic control, has a cavity quality regulation function and realizes quantum memory by cavity induced transparency.

The invention discloses a quantum resource limited semi-quantum secret sharing method. Semi-quantum secret sharing usually includes that a quantum side Alice divides a secret into two parts and sendsthem to quantum resource limited Bob and Charlie respectively, and only when the Bob and the Charlie cooperate, the complete secret be recovered. At present, the typical semi-quantum secret sharing method guarantees the security, but requires the semi-quantum sides Bob and Charlie to perform quantum measurement operations. The measurement device may be unsafe, which increases the hidden danger ofsecret sharing. The present invention enables the resource limited Bob and Charlie to perform secret sharing without a quantum measurement device, and the quantum side Alice does not require quantum memory. In this way, the present invention can greatly reduce the quantum resources required by the three participants, thereby saving the communication cost.

The invention discloses a quantum secret sharing method and system based on tensor network state dynamic compression, and the method comprises the following steps: S1, enabling a dispatcher to carry out the local equidistant transformation of quantum state secret information needing to be shared in a mode of a matrix product state, and decomposing the quantum state secret information into corresponding secret shares according to the number of participants; S2, enabling the dispatcher to dispatch the decomposed secret share to the corresponding participant; S3, enabling the participants to share the secret shares obtained by themselves; and S4, acquiring the process information of the local equidistant transformation from the distributor by the participants acquiring all secret shares, andrecovering the shared quantum state secret information in combination with decompression. The method and the system have the advantages that all classic participants and quantum participants can use quantum bits with the quantity index higher than that of the quantum bits received by the participants to decompress the state, the obvious storage advantage is achieved, the quantum communication efficiency and precision are improved, and the size of a quantum memory is greatly reduced.

A quantum memory device relates to the field of quantum information technology, including a pump light module, a quantum memory module, and an orbital angular momentum analysis module; the pump lightmodule is for producing pump light and generating a signal photon of an optical signal to be stored and outputting pump light and signal photons to the quantum memory module through a quantum channel;the quantum memory module is configured to combine received pump light and signal photons and convey signal photons to the orbital angular momentum analysis module for analysis; the orbital angular momentum analysis module is used for analyzing orbital angular momentum quantum states of received signal photons to enable multi-mode operation of high-dimensional quantum state storage and spatial domain. The present invention provides a spatially multiplexed quantum storage device that is easier to implement and can store high-dimensional quantum states.

The present invention provides a single photon source device, a preparation method and a quantum memory. The single photon source device comprises: a quantum dot luminescent layer, wherein the quantumdot luminescent layer comprises a barrier layer and a quantum dot layer in the barrier layer; a piezoelectric ceramic substrate, wherein the central wavelength of the luminescent spectrum of the quantum dot luminescent layer can be adjusted through the piezoelectric ceramic substrate; and a bonding layer, wherein the bonding layer is arranged between the quantum dot luminescent layer and the piezoelectric ceramic substrate, and the quantum dot luminescent layer is connected with the piezoelectric ceramic substrate through the bonding layer. According to the technical scheme of the present invention, by using a piezoelectric ceramic substrate, the single photon source device has the advantages that a large wavelength adjustment range can be achieved, the wavelength can be bidirectionally adjusted, the compact on-chip integration trend can be satisfied and the test device is simple.

The invention discloses a key value storage system and method based on a quantum algorithm. The key value storage system and method are used for improving the data retrieval request processing efficiency. In the system, a non-quantum processor is used for sending a data retrieval request of first data. The FPGA is used for converting the data retrieval request into first processing information which can be recognized by the quantum processor. The quantum processor is used for using a quantum algorithm to concurrently retrieve first storage address information of the first data in a memory corresponding to the quantum processor based on different quantum bits and the first processing information, and sending the first storage address information to the FPGA. The FPGA is used for convertingthe first storage address information into second storage address information which can be recognized by the non-quantum processor and sending the second storage address information to the non-quantumprocessor. The non-quantum memory is used for receiving a data acquisition request which at least comprises the second storage address information and is sent by the FPGA or the non-quantum processor, and sending the first data to the non-quantum processor according to the data acquisition request.

The invention discloses an orbital angular momentum key distribution method based on an odd coherent light source and quantum storage. An odd coherent light source is used for replacing a weak coherent light source, the number of single photons in sent pulses is increased, the number of multiple photons is reduced, and therefore the safety key generation rate of measurement equipment irrelevant quantum key distribution is increased, and the bit error rate is reduced. According to the method, orbital angular momentum coding is used for replacing polarization coding, the dependency problem of bases in quantum key distribution is solved, the security key generation rate is further increased, and the bit error rate is reduced; by adding the quantum storage unit, the secure transmission distance of the OAM-MDI-QKD protocol is significantly increased, and the key generation rate and the secure transmission distance are improved. According to the invention, long-distance QKD without quantum relay can be realized only by using single-mode quantum storage, and the coherence time required by a quantum memory in the protocol is shorter than the coherence time required by a quantum relay protocol.

Devices, systems, and methods for ambient-temperature quantum information buffering, storage, and communication are provided enabling receiving a quantum communication (for example, photons holding quantum information, e.g., qubits), storing the qubits in a room-temperature scalable quantum memory device, selectively retrieving the qubits, performing filtering, and extracting the quantum communication with a controllable delay.

The invention relates to a frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband. An entangled photon pair is output at a high speed by adopting a frequency domain broadband entangled light source; secondly, establishing entanglement of a photon-quantum memory at a high speed through a storage effect of the multichannel quantum memory on photons of a plurality of frequency channels; establishing quantum entanglement among the multi-channel quantum memories at a high speed in a declaring form through a multi-channel Bell state measuring device; andfinally, according to a multi-channel Bell state measurement result, the multi-channel quantum memory can output entangled photon pairs with the same frequency at a high speed, so that the fidelity and the transmission rate of quantum bit transmission in a quantum channel can be improved. All devices used in the invention can be from mature photoelectronic devices, which is beneficial to system assembly preparation and practical development, and the whole device has the characteristics of easy assembly, miniaturization, practicability and integration of optical fiber devices.

The invention belongs to the field of array signal processing, specifically relates to a wideband direction finding method based on a search evolution mechanism of a quantum charged system. The methodcomprises the following steps: establishing a wideband signal sampling model; initializing the parameters of the search evolution mechanism of the quantum evolutionary system; calculating the fitnessof all charged particles and sorting in descending order; creating a quantum memory library of charged particles; updating the charged amount of charged particles and the distance between them; updating the moving probability and the applied combined force of the charged particles; updating the quantum rotation angle, the quantum position and speed of the charged particles; calculating the fitness of the charged particles and sorting in descending order; updating the quantum memory library; judging whether the maximum number of iterations is reached; and outputting a global optimal quantum position of the quantum charged system to map into an optimal position. The wideband direction finding method based on the search evolution mechanism of the quantum charged system uses the search evolution mechanism of the quantum charged system to perform direction finding on the wideband signals, which simplifies the calculation and reduces calculation time, improves the convergence speed and convergence precision, and realizes a fast and high precision direction finding.