37 results about "Quantum memory" patented technology

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 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 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.

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 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 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.

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.

The application provides a quantum storage device, a preparation method and a quantum device, and relates to the technical field of quantum storage devices. The quantum storage device comprises a substrate, a superconducting circuit, at least two support parts, at least two diffusion regions and a superconducting mechanical oscillator. The at least two support parts are arranged vertically on a first surface. The at least two diffusion regions are arranged one by one with the support parts. The at least two diffusion regions are connected with the superconducting mechanical oscillator, so that the superconducting mechanical oscillator is arranged in suspension on the first surface. The superconducting mechanical oscillator comprises a suspension part and at least two cantilever beams, and the cantilever beams are arranged one by one with the diffusion regions. The direction of each cantilever beam is different, so that the at least two cantilever beams jointly form a first branch structure, and the first branch structure is used for reducing the dissipation of vibration energy of the suspension part for the first time based on a dissipative dilution mechanism. The application can guarantee the mechanical stability of the superconducting mechanical oscillator and the preparation yield, and can reduce mechanical loss and improve the quality factor.

Quantum memory The invention relates to an assembly (11) for a quantum memory (10), the quantum memory (10) being suitable to store and retrieve a quantum information encoded into an optical signal, the assembly (11) being deprived of optical cavity and comprising: - a vacuum chamber (12), - a neutral atoms source (14) suitable to generate neutral atoms in the vacuum chamber (12), and - a magneto-optical trap generator (16) suitable to generate an elongated magneto-optical trap enabling to trap neutral atoms in the vacuum chamber (12) so as to obtain an elongated ensemble of neutral atoms elongated along a so-called elongation axis, the elongation axis being along a vertical direction, the optical signal being intended to propagate in the vacuum chamber (12) along the elongation axis, the quantum information being stored in the elongated ensemble of neutral atoms or being retrieved from the elongated ensemble of neutral atoms depending on a control signal.

The invention provides a quantum memory device, a preparation method and a quantum device, and relates to the technical field of quantum memory devices. The quantum memory device includes a substrate, a superconducting circuit, at least two support portions, at least two diffusion regions, and a superconducting mechanical oscillator. The at least two supporting parts are vertically arranged on the first surface. The at least two diffusion areas are in one-to-one correspondence with the supporting parts. And the at least two diffusion regions are connected with the superconducting mechanical oscillator, so that the superconducting mechanical oscillator is suspended on the first surface. The superconducting mechanical oscillator comprises a suspension part and at least two cantilever beams, and the cantilever beams and the diffusion areas are arranged in a one-to-one correspondence mode. The orientations of the cantilever beams are different, so that the at least two cantilever beams jointly form a first branch structure, and the first branch structure is used for reducing the dissipation of the vibration energy of the suspended part for the first time based on a dissipation dilution mechanism. According to the invention, the mechanical stability and preparation yield of the superconducting mechanical oscillator can be ensured, the mechanical loss can be reduced, and the quality factor can be improved.

A quantum data processing system and method are provided. A computer-implemented method may include: storing multiple copies of a quantum state in a quantum memory, wherein the quantum state encodes properties of a target system; loading the multiple copies of the quantum state in the quantum memory into a quantum computer; processing the multiple copies of the quantum state by the quantum computer to obtain a purified quantum state; and measuring the purified quantum state to determine properties of the target system.

A quantum memory device includes: a waveguide configured to spatially confine paths of photons therein; a memory cell that includes a micro-ring resonator (MRR), a frequency tuner, and a quantum memory material portion, wherein the MRR includes a first segment that is parallel to a segment of the waveguide, wherein the frequency tuner is configured to modulate a photon resonance frequency in the MRR by modifying an effective refractive index within, or around, a second segment of the MRR, and wherein the quantum memory material portion includes a quantum memory material having a ground state and an excitation state that stores photons therein and located within or on a third segment of the MRR; and a control circuit configured to modulate the photon resonance wavelength in the MRR during a first step of a photon capture operation to match a predefined wavelength, and to generate captured photons in the MRR.

The application relates to a tunable light-quantum memory entanglement generation device based on atomic transition interference and belongs to the technical field of quantum information science technology. In the application, a multi-energy-level atomic system is used as an atomic medium for preparing a quantum memory; atoms in an initial state in the atomic medium are transitioned to a coherent superposition state of multiple excited states under the action of excitation light; the atoms in the coherent superposition state of the multiple excited states are transitioned to a ground state, forming a coherent superposition state of multiple light-quantum memory entangled states, that is, atomic transition interference occurs; the frequency of the excitation light can be adjusted to change the coefficients of the coherent superposition of the light-quantum memory entangled states, so that the photons output from the atomic medium and the quantum memory of the spin state of the storage atom are in a tunable quantum entangled state. In the application, each component for preparing the tunable light-quantum memory entanglement can be obtained from a mature optoelectronic device.

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

A system includes a quantum memory configured to store a quantum cryptographic key, a unique random key, and sensitive data to be transmitted to a quantum computing device over an optical communication channel. The system further includes a quantum processor operably coupled to the quantum memory and configured to access the quantum cryptographic key and the sensitive data and to transmit, over the optical communication channel, the quantum cryptographic key to the quantum computing device. In response to transmitting the quantum cryptographic key to the quantum computing device, the quantum processor is further configured to encode the sensitive data based on the quantum cryptographic key and a unique random key. The encoded sensitive data includes a generated one or more pairs of entangled quantum bits (Qubits). The quantum processor is further configured to transmit, over the optical communication channel, the encoded sensitive data to the quantum computing device.

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 technology described herein is directed towards a multi-bit random-access quantum memory (RAQM) system based on reconfigurable tunable resonators. The RAQM system includes an array of (e.g., four) tunable high-Q resonators which, when one is tuned to the same frequency as a common (shared) broadband tunable low quality resonator, strongly interact to write a qubit to the high-Q resonators, and similarly readout a previously stored qubit. The shared low-Q and multiple high-Q resonators can be fabricated in a monolithically-integrated stack, without consuming a large circuit footprint or chip area. The low-Q resonator can be coupled to an external feed-line to obtain the qubits through a circulator, facilitating efficient read / write operations from and to the quantum memory storage portion of the RAQM system. In one implementation, the circulator is a magnet-less circulator, facilitating deployment of the RAQM system at cryogenic temperatures.

The invention discloses a quantum storage compression structure supporting online calculation, which is characterized in that the compression structure comprises an input module, a compression module, a conversion module, a calculation module and a decompression module, and the input module is used for converting an input form of an initial state vector and a quantum circuit into an identified legal form; the compression module is used for compressing and converting the state vector into a linked list for storage through a vernier, and compressing and unloading the periodic data again; the conversion module is used for converting the quantum circuit into a form which can be processed by RepeatCounter; and the decompression module decompresses the output stream or the memory according to requirements, and decompresses and destroys the RepeatCounter when the memory is limited. Compared with the prior art, the method has the advantages of optimization of storage space, reduction of calculation loss, efficient parallel support and the like, online quantum calculation can be performed without frequent compression and decompression, frequent internal and external memory exchange caused by offline compression can be reduced, and larger-scale quantum calculation can be better simulated on a machine with lower configuration.

This invention provides a quantum storage device and a quantum storage method based on an optical resonant cavity. The quantum storage device includes: a light generation module that emits pump light and an optical signal; an electrical pulse generation module that generates an electrical pulse signal corresponding to the optical signal according to a preset storage method; the storage module includes a rare-earth-doped crystal, wherein a first reflective film on a first surface and a second reflective film on a second surface of the rare-earth-doped crystal constitute an optical resonant cavity, with the first and second surfaces forming a preset angle to change the resonant frequency of the optical resonant cavity; an optical waveguide array disposed inside a third surface of the rare-earth-doped crystal; an electrical waveguide array disposed on the third surface and electrically connected to the electrical pulse generation module, and changing the absorption band structure of rare-earth ions through the electrical pulse signal; the optical signal is coupled into the optical resonant cavity through the optical waveguide array, interacts with rare-earth ions within the optical resonant cavity, and excites the population of rare-earth ions to the upper optical energy level to store the optical signal.

Systems and techniques for active quantum memory (AQM) and quantum circuits with feedback are described. For instance, one or more aspects of the present disclosure may enable the indefinite storage of one or more qubits via a sequence of quantum teleportations or quantum swaps involving the rapid periodic executions of a standard teleportation or swap protocols with feedback (e.g., provided the total feedback cycle time is less than the decoherence time for a qubit). The stored quantum state may be passed repeatedly back-and-forth between two of the qubits, and the stored quantum state may be maintained by the input energy on each cycle required to initialize the entangled qubit pair (e.g., where the cycle period is chosen to be less than the decoherence time of the qubits to maintain state information over many cycles).