62 results about "Quantum memory" patented technology

The invention discloses a switch secure communication encryption method based on quantum key distribution. The method comprises the following steps: a service party submits a'security-delay-bandwidth 'intention to a zero-trust brain through a quantum policy intention description language; evaluating the real-time quality, key margin and topology accessibility of an optical fiber quantum channel, a classical ultra-high-speed channel and a radio frequency space channel according to intention requirements; triggering a QKD transmitting end and a receiving end to perform quantum state transmission of polarization and OAM coding along the optimal quantum path, completing basis vector comparison, error code verification and privacy amplification, generating a root quantum key, and injecting the root quantum key into an on-chip quantum memory; when a data packet arrives at a switch port, the assembly line takes out Kroot from the first-level key pool, and derives a one-time session key through the HMAC-SHA3; continuously monitoring a quantum channel bit error rate, a key pool margin and an AI abnormal score; and the transmitting and receiving parties synchronously confirm and destroy the session key, write all key life cycle events into a quantum invariant account book, and realize second-level auditing evidence obtaining through block chain hash anchoring.

A quantum memory device 100 for storing a signal field 170 comprises an optical cavity comprising a first and second reflective surface 110, 120, a first and a second optical element 130,140 within th

A method for routing in a quantum network is provided. The method may include receiving parameters including a fidelity with coherence decay time and an entanglement generation rate for each quantum node in a mesh quantum network by a controller, the controller being configured to communicate with each quantum node of a plurality of quantum nodes in the mesh quantum network. Each quantum node includes a quantum memory and a processor. The method may also include analyzing the fidelity with coherence decay time and the entanglement generation rate to yield a determination of a path fidelity with a path coherence decay time and a path entanglement generation rate between at least one pair of quantum nodes. The method may further include, based on the determination, selecting a quantum communication path from a source node to a destination node.

A system includes a quantum memory configured to store sensitive data to be transmitted to a quantum computing device over an optical communication channel and a quantum processor operably coupled to the quantum memory and configured to generate pairs of entangled quantum bits (QuBits), and further encode each pair of the pairs of entangled QuBits based on the sensitive data. The pairs of entangled QuBits include the sensitive data. The quantum processor is further configured to store the pairs of entangled QuBits to a predetermined quantum storage medium configured to maintain a state of each pair of the pairs of entangled QuBits, identify, based on a change in state associated with one Qubit of a pair of the pairs of entangled QuBits, an unauthorized measurement of the pairs of entangled QuBits, and in response to identifying the unauthorized measurement, cause the pairs of entangled QuBits to be rendered unreadable.

The invention provides an apparatus for quantum communication in a quantum network configured to create an entangled pair of quantum information carriers comprising a first quantum information carrier and a second quantum information carrier, transmit the first quantum information carrier to a remote device, store the second quantum information carrier in a quantum memory, receive, from the remote device, information about a phase correction related to the transmission of the first quantum information carrier, and apply the phase correction to the second quantum information carrier.

The invention provides a quantum state protocol construction system, and relates to the technical field of quantum communication, an Alice end modulates an optical pulse into a quantum optical pulse bearing two mutually orthogonal polarization states, and the quantum optical pulse is sent to a Bob end through an optical fiber link; the Bob end receives the quantum light pulses sent by the Alice end, extracts one light pulse, disorganizes the time sequence of the other light pulses, and returns the light pulses to the Alice end through an optical fiber link; and the Alice end realizes measurement of quantum state information of the light pulse by detecting the returned light pulse, and determines the type of one light pulse extracted by the Bob end. Based on the setting of a quantum multi-party security computing protocol device in quantum communication, the use of immature quantum related equipment such as a quantum memory and a high-dimensional entanglement quantum measurement device at present is avoided, and the application range of the protocol is enlarged.

A system and method are provided for entanglement assisted quantum sensing. An entangled source generates entangle photon pairs that include a signal photon and an idler photon. The signal photon is modulated and transmitted to a target. In the monostatic configuration, the idler photon stays at the radar, where the idler photon passes through a quantum memory or delay line and an optical phase-conjugate module. The radar return signal includes signal photons that have interacted with the target (e.g., reflected from the target). The received signal photons are detected using balanced homodyne detection by beating the received signal photons against the phase-conjugate idler photons, which function as a local oscillator. The target is detected using a cross-correlation between the electrical signal from the homodyne balanced detector and the modulation pattern used to modulate the signal photons.

The present invention relates to a quantum information storage device (100) comprising a vacuum chamber (2), a plurality of waveguides (4) configured to propagate light of wavelength λ, each waveguide (4) having a narrower cross-sectional segment with a minimum lateral dimension less than λ, and an atomic trap configured to trap a single atomic cloud (20) around the narrower cross-sectional segment of the plurality of waveguides.

A quantum memory device for storing a signal field is provided. The quantum memory device comprises an optical cavity comprising a first reflective surface and a second reflective surface; a first optical element and a second optical element arranged within the optical cavity; an atomic system situated between the first optical element and the second optical element, the atomic system configured to store the signal field via an atomic transition; and one or more magnets configured to apply an axial magnetic field across the atomic system.

The invention belongs to the technical field of commercial cipher system testing, and particularly relates to a quantum random number generator-based commercial cipher system entropy source quality detection method, which comprises the following steps of: acquiring shot noise of a light quantum detector at a high sampling rate, removing direct current bias by using a moving average subtraction method, and acquiring a quantum fluctuation sequence of a zero mean value; based on a variance ratio of the sequence and short-range autocorrelation, nonlinear mapping of an exponential function is utilized to obtain correlation degree so as to amplify a weak non-quantum memory effect; obtaining an evaluation model containing hyperbolic cosine and a logarithmic function by combining the drift potential energy of the bias voltage relative to the target value and the aging time of the device, and obtaining a dynamic entropy loss index; and comparing the entropy loss index with a preset threshold value, and executing self-adaptive bias current feedback regulation or triggering hardware fusing according to a comparison result. According to the invention, the problem of recessive degradation of the entropy source caused by drifting of the working point of the detector is solved, and accurate closed-loop control of the quality of the entropy source is realized.

Solution synthesis of rare-earth-doped nanoparticles, followed by flash sintering of the nanoparticles, can produce rare-earth-doped transparent polycrystalline ceramics with beneficial optical and / or mechanical properties, such as low optical losses, high optical coherence, high refractive-index controllability, and / or high mechanical strength. In one example application, high-quality erbium-doped yttria for quantum memory devices can be fabricated.

The present application belongs to the technical field of commercial cipher system test, and particularly relates to a method for detecting the quality of an entropy source of a commercial cipher system based on a quantum random number generator, which comprises: obtaining shot noise of an optical quantum detector at a high sampling rate, removing direct current bias by using sliding average subtraction, and obtaining a quantum fluctuation sequence with zero mean; obtaining a correlation degree by using nonlinear mapping of an exponential function based on the variance ratio and short-range autocorrelation of the sequence, so as to amplify weak non-quantum memory effects; obtaining an evaluation model containing a hyperbolic cosine and a logarithmic function by combining the drift potential of a bias voltage relative to a target value and the aging time of a device, so as to obtain a dynamic entropy loss index; and comparing the entropy loss index with a preset threshold value, and performing adaptive bias current feedback adjustment or triggering hardware fusing according to the comparison result. The present application solves the problem of implicit degradation of an entropy source caused by drift of a detector operating point, and realizes precise closed-loop control of the quality of the entropy source.

A permanent defect qubit repair system using a redundant repair circuit at a quantum circuit level, includes: automatic test equipment configured to provide a fault address table with information of a permanent fault address (FA) and a spare address (SA) for replacing the FA to a quantum memory; a redundant repair circuit configured to constitute a circuit to repair a permanent defect qubit consisting of an address comparison and address replacement process and transfer an updated memory address to an address routing circuit; and the quantum memory comprising the address routing circuit configured to receive the updated memory address from the redundant repair circuit and then route the updated memory address to a memory cell according to an address value.

A quantum memory manager (QMM) of a source endpoint obtains a memory request from a quantum application for quantum memory blocks. The source endpoint negotiates with a destination endpoint to determine a memory lifetime value that includes a minimum decoherence time for qubits stored at the source endpoint and qubits stored at the destination endpoint. The QMM allocates a quantum memory block of a plurality of qubit storage locations to the quantum application based on the memory lifetime value. The QMM receives communication qubits that are entangled with destination qubits sent to the destination endpoint, and stores the communication qubits in the quantum memory block. Each particular communication qubit of the communication qubits is entangled with a particular destination qubit of the destination qubits.

Methods for fabricating optically active quantum memories into quantum-grade diamond thin films and then bonding them to semiconductor substrates are described. Semiconductor substrates are optically and electronically functionalized in preparation for using a flip-chip bonding technique to bond the functionalized substrates to overgrown diamond thin films that host color centers. By purposefully growing quantum-grade diamond thin films and implanting them with color centers separately from fabrication processes that functionalize the substrates, the high quality, purity, and crystallinity of the thin films are preserved, while also allowing for further customization of the types of color centers that are implanted into the diamond.

Techniques for generating and maintaining a buffer of on-demand, pairwise quantum entanglement instances using programmable optical switchboard architectures within quantum repeaters are disclosed. A rate of establishing pairwise quantum entanglement instances between quantum repeaters of a quantum entanglement network may be higher than both a rate of decay of said instances and a rate of consumption of said instances for providing distributed quantum entanglement, such that on-demand distribution of quantum entanglement may be provided for customers. Furthermore, an optical switchboard with a given quantum repeater may be configured to route between any of the quantum memory locations provided within the quantum repeater, such that an optimization of the usage of such buffers of quantum entanglement instances may be ensured.

The invention provides a design method and device of a quantum memory architecture and a storage medium. The method comprises the following steps: receiving a physical quantum bit specification and an environmental noise model constructed based on environmental noise; selecting a continuous symmetric group according to the interaction between the physical quantum bit specification and the environmental noise; synthesizing a quantum state code in the symmetrically protected subspace through a continuous symmetric group; a control pulse sequence for keeping symmetric protection is designed through a continuous symmetric group; and outputting a quantum memory architecture specification according to the quantum state code and the control pulse sequence, including: in an access stage of the quantum memory, actively and dynamically decoupling the quantum state of the quantum memory from the environmental noise based on the control pulse sequence. On the basis, the quantum memory architecture adopting the continuous symmetric groups to realize symmetric protection can reduce the number of physical quantum bits of the quantum memory and simplify the error correction overhead.

A method performed by a first device according to an embodiment of the present specification comprises the steps of: measuring first entanglement photons based on entanglement photon pairs; determining first measurement values based on the same bases as second bases among first measurement values for the first entanglement photons; and transmitting a message to a second device. The message is generated on the basis of the determined first measurement values and message information of the first device.

The technology described herein is directed towards a cryogenic magnet-less circulator device, in which the circulator device is based on the spatiotemporal modulation of angular momentum for microwave photons, controlled using a modulated control signal. The circulator device is configured for integration with a quantum computer, e.g., to facilitate qubit measurements. The circulator topology and design are based on tank circuits, e.g., arranged in a star topology with different sets of radio frequency superconducting quantum interference devices (rf-SQUIDS) per tank circuit, that resonate out-of-phase based on the modulated control signal. The circulator can be fabricated on a layered superconducting chip using standard semiconductor processes, allowing one or more circulators to be integrated on the same superconducting chip as the qubits. A classical computer can be used to output the modulated control signal, and adapt the modulated control signal as needed under varying conditions.

Methods, systems, and apparatus for quantum data processing. In one aspect, a method includes storing, in a quantum memory, multiple copies of a quantum state, comprising, for each copy of the quantum state, i) probing, by an initialized quantum sensor, a target system to obtain an evolved quantum state of the quantum sensor, ii) transducing the evolved quantum state of the quantum sensor into a quantum state of a quantum buffer, iii) logically encoding the quantum state of the quantum buffer into a quantum error correcting code, and iv) moving the logically encoded quantum state of the quantum buffer into the quantum memory; loading the multiple copies of the quantum state in the quantum memory into a quantum computer; processing, by the quantum computer, the multiple copies of the quantum state to obtain a purified quantum state; and measuring the purified quantum state to determine properties of the target system.

Methods for fabricating optically active quantum memories into quantum-grade diamond thin films and then bonding them to semiconductor substrates are described. Semiconductor substrates are optically and electronically functionalized in preparation for using a flip-chip bonding technique to bond the functionalized substrates to overgrown diamond thin films that host color centers. By purposefully growing quantum-grade diamond thin films and implanting them with color centers separately from fabrication processes that functionalize the substrates, the high quality, purity, and crystallinity of the thin films are preserved, while also allowing for further customization of the types of color centers that are implanted into the diamond.

A system 500 comprises a quantum card issuer authority 502, a quantum card reader 504 and a quantum card 506. The quantum card 506 comprises a quantum memory 508 and a classical memory 509. The quantum memory 508 comprises a quantum system capable of storing a currency state generated by the quantum card reader or the quantum card issuer authority 504. The classical memory 509 is configured to store a serial number associated with a user.

Methods and apparatuses are disclosed for improving quantum information storage and retrieval to / from in matter-based quantum memory devices. A first mapping procedure triggers an interaction between a signal field and the memory. This causes a first retrieval or storage event. The signal field is then redirected to re-enter the memory where a second mapping procedure is enacted to trigger a second interaction between the signal field and the memory resulting in a second storage or retrieval event. A phase difference is used to mediate the second interaction to cause enhanced storage or retrieval.

A rare-earth-doped antiferromagnetic crystal is disclosed, designed to achieve long optical coherence times and enable coherent coupling between optical and magnon modes. The crystal includes a host lattice, such as gadolinium vanadate, gadolinium oxide, or gadolinium silicate, which is antiferromagnetic below a Néel temperature and is doped with a second rare-earth ion, such as erbium. By operating at cryogenic temperatures, electron spins in the host are magnetically ordered, providing a quiet magnetic environment that minimizes decoherence for the dopant ions. The system achieves long optical coherence times for the rare-earth dopant ions, supporting robust quantum memory and communication. Additionally, coherent coupling between the optical transitions of the dopant and magnon modes of the host enables efficient microwave-to-optical quantum transduction. Isotopic purification of the host and / or dopant ions can further reduce nuclear spin noise, enhancing coherence times.

Techniques for implementing a QRAM by routing quantum information through multiple modes of a bosonic system are described. According to some aspects, a single bosonic system may be configured to maintain quantum information in a large number of independent modes at the same time. Suitable operations upon these modes may allow a quantum address value to be routed to modes associated with respective bits such that the only modes altered by the operations are those associated with the addresses being accessed. These modes may be operated upon based on the stored values then extracted to obtain the desired correlated superposition of the stored bit values in the addresses. The bits stored at the address locations may be classical bits, or may be qubits.

A system and method for providing quantum entanglement as a service are described. Intermediate nodes which may be located in trusted or trustless locations are used to distribute quantum entanglement to endpoints, such as endpoints of customers of a quantum entanglement distribution service. The distributed quantum entanglement provides a secure communication path that does not rely on trust placed in an infrastructure or software provider. To distribute the quantum entanglement, intermediate nodes comprising quantum memories are used. Joint measurements are performed on quantum particles of respective entangled quantum pairs received at the intermediate nodes without collapsing superposition states of the particles. This allows for the quantum entanglement to be extended across intermediate nodes while maintaining entanglement and superposition of the entangled quantum particles.

A quantum computing system comprising a reconfigurable quantum processing unit optically coupled to a photon source and a photon detector and having a plurality of Mach-Zehnder interferometers (MZIs); and a controller communicatively coupled to the plurality of MZIs and configured to generate a control signal to alter a phase setting of at least one of the plurality of MZIs, and the plurality of MZIs configured to alter a phase of one or more photons passing through the plurality of MZIs. Further, the quantum computing system comprises a quantum memory array having a plurality of quantum memories optically coupled to the plurality of MZIs, wherein each quantum memory is configured to absorb a photon received by the quantum memory comprising quantum information and release a photon comprising quantum information of the received photon into the reconfigurable quantum processing unit.

Improved receiving device for a ground-to-surface interface of a quantum information network. This device (10) comprises: an optical unit (11) for capturing an entangled photon emitted at an emission frequency ( ) from a satellite (3), a frequency converter (16), and a quantum memory (14) for storing entangled photons, the frequency converter comprising: a nonlinear crystal (50); a tunable source (52); and control means (54) for the tunable source, the nonlinear crystal generating a secondary entangled photon from the captured entangled photon and a conversion photon generated by the tunable source, the control means controlling the tunable source to modify a generation frequency of the conversion photon so that the secondary entangled photon is compatible with the quantum memory, while the captured entangled photon has its emission frequency affected by a Doppler shift due to the satellite's movement.Figure for the abbreviation: Figure 1.

A passively protected quantum memory operates in two dimensions using a square lattice of harmonic oscillators. Each harmonic oscillator is subjected to a coherent two-photon drive process and an incoherent two-photon loss process. The oscillators are coupled to their nearest neighbors via a ferromagnetic Ising parity-parity interaction. A cold bath coupled to the oscillators facilitates an energy dissipation process that aligns the parities of neighboring oscillators. This configuration passively suppresses phase-flip and bit-flip errors without active error correction cycles.

Techniques for generating and maintaining a buffer of on-demand, pairwise quantum entanglement instances using programmable optical switchboard architectures within quantum repeaters are disclosed. A rate of establishing pairwise quantum entanglement instances between quantum repeaters of a quantum entanglement network may be higher than both a rate of decay of said instances and a rate of consumption of said instances for providing distributed quantum entanglement, such that on-demand distribution of quantum entanglement may be provided for customers. Furthermore, an optical switchboard with a given quantum repeater may be configured to route between any of the quantum memory locations provided within the quantum repeater, such that an optimization of the usage of such buffers of quantum entanglement instances may be ensured.