73 results about "Quantum measurement" patented technology

The invention provides a time-resolved single-photon counting two-dimensional imaging system and a time-resolved single-photon counting two-dimensional imaging method and belongs to the technical field of extremely-weak light detection. A trigger 2 is triggered to start sampling, centralized sampling is performed at t time intervals, and measurement and counting are performed if light comes at the intervals, so that time resolving of an extremely-weak light object is realized, and a time sequence image is generated. Imaging is performed on the basis of a compressive sensing (CS) theory, a digital micro-mirror device (DMD5) performs linear random projection on a compressible two-dimensional image, the compressible two-dimensional image is optically modulated and then synchronously detected by using a single-photon counter, and a high-resolution extremely-weak light image can be reconstructed by a small amount of sampling operation. The measurement process is linear and non-adaptive, the reconstruction process is non-linear, and the invention has the advantages of high generality, robustness, expandability, superposition and computation asymmetry, and can be widely applied to the fields of life science, medical imaging, data acquisition, communication, astronomy, military affairs, hyper-spectral imaging and quantum measurement.

The invention includes systems for and methods of performing quantum computation. The method of quantum computation includes preparing a set of one or more qubits capable of storing quantum information in 2ⁿ possible states, wherein the number of qubits n≧1. The qubit set is subject to a decoherence mechanism that could cause a loss of quantum information stored in some but not all of the qubit states. The method also includes determining, via a quantum measurement of the qubit system or just by analyzing the decoherence of the qubit states, which of the 2ⁿ states or their superposition is/are not susceptible to decoherence. The method further includes encoding and processing quantum information in one or more of the decoherence-free states by controlling qubit-qubit interactions or via an electromagnetic interaction with the set of qubits.

The invention discloses a scalable low-latency feedback control device for quantum bits. The device realizes the feedback control of the quantum states of multiple quantum bits by means of digital signal processing technology and a quantum mechanical principle based on a high-speed microwave baseband signal transceiving hardware circuit board. The quantum feedback control device designed in the present invention is different from the feedback control applied in the classic field, and can generate synchronous microwave pulses for operating superconducting quantum bits, can accurately define thenumber of times, the time and the strength of quantum measurement, demodulates measurement signals in real time, deploys a quantum feedback algorithm on an FPGA, and has extremely low feedback delayand excellent scalability so as to accurately control a system integrating multiple quantum bits and to satisfy a requirement for running a measurement-based quantum error correction algorithm on a quantum chip.

The present disclosure relates to a generally-applicable measurement technique based on coherent quantum enhancement effects and provides embodiments with nonlinear optics. The technique utilizes parametric nonlinear processes where the information-carrying electromagnetic quanta in a number of electromagnetic modes are converted phase coherently to signature quanta in a single mode or a few modes. The phase coherence means that while the quanta before conversion may have unequal or uncertain phase values across the modes, the signature quanta converted from those different modes have the (near) uniform phase. This can lead to significant increase in the signal to noise ratio in detecting weak signal buried in strong background noise. Applications can be found in remote sensing, ranging, biological imaging, field imaging, target detection and identification, covert communications, and other fields that can benefit from improved signal to noise ratios by using the phase coherent effect.

The invention provides an inter-satellite ranging method based on quantum light sources on satellites and a reflector. The quantum light sources on the satellites and a quantum measuring device are arranged on a user satellite and used for generating and emitting entangled-state photon pulse signals, the reflector and a pointing mechanism are arranged on a beacon satellite and used for reflecting the received entangled-state photon pulse signals to the user satellite, and the user satellite measures the high-precision distance between the user satellite and the beacon satellite by measuring the difference of arrival times of the emitted entangled-state photon pulse signals and the reflected entangled-state photon pulse signals. By means of the method, constellation satellite autonomous navigation tasks based on measurement of inter-satellite distances can be achieved, the degree of dependence of the satellites on the ground measurement and control can be reduced, and the autonomous viability of a constellation system under emergency conditions can be enhanced.

The invention discloses a high-precision magnetic field meter based on novel weak quantum measurement. The magnetic field meter comprises an LED white light source, an initial state preparing system, a magnetic light coupling system and a detection system; the LED white light source generates wide-spectrum photons which interact with a magnetic field; the initial state preparing system collimates the wide-spectrum photons generated by the LED light source, and prepares a polarization state of the wide-spectrum photons into a needed quantum state; the magnetic light coupling system couples the wide-spectrum photons prepared into the quantum state with the magnetic field, and then output the coupled photons; the detection system converts a circular polarization state of the wide-spectrum photons into a linear polarization state, introduces a stable offset bias phase difference between horizontal and vertical polarization in the linearly polarization state, and sets a working point of the system in a most sensitive area; polarization-state projection is carried out to implement post selection of the wide-spectrum photons, and the spectral distribution of the wide-spectrum photons after post selection is measured; and change of the magnetic field intensity where a magneto-optic coupling system is placed is measured by comparing change of the spectral distribution. According to schemes of the invention, the specific bias phase difference is used to change the working point of traditional weak measurement, and the measuring precision is improved greatly. Compared with a superconductive quantum interference magnetic field meter, similar resolution can be reached needless of a low-temperature device or an interference device, the cost is low, and the working state is stable.

The invention discloses a two-party quantum private comparison method based on a five-quantum bit entangled state. The two-party quantum private comparison method is used for comparing whether secrets of two users are equal or not in size. The two-party quantum private comparison method has the advantages that the method needs help of a semi-loyal third party (Third Party, TP), the TP is allowed to mistakenly act according to the wish of the TP, but is not allowed to conspire with any one of the two users; one five-quantum bit entangled state can be used for achieving two-bit equality comparison in all comparison; unitary operation and the quantum entanglement swapping technology are not required in the method, it is avoided that expensive quantum devices related by unitary operation and the quantum entanglement swapping technology are consumed; Bell measurement and single-particle measurement are only adopted in the method, and the quantum measurement can be achieved with the existing quantum technology; safety performance according to outside attack and participant attack is guaranteed; secret information and the comparative result of the two users are not revealed to the TP.

The invention belongs to the field of quantum information, in particular to a method for generating two-photon radiation on the basis of a single quantum dot. Generation of two photons has great significance in the quantum information field such as quantum key distribution, quantum entanglement, quantum measurement and the like. The method for generating two-photon radiation on the basis of the single quantum dot is provided and comprises steps as follows: firstly, a near infrared single quantum dot is prepared on a slide with a indium tin oxide film formed through evaporation plating; then, indium tin oxide nanoparticles cover the single quantum dot; the indium tin oxide nanoparticles are spin-coated with polystyrene polymer films, and influence of the external environment on the quantum dot is effectively isolated; laser co-focusing is performed on the sample, and two-photon fluorescence radiation is generated for the single quantum dot. With the adoption of the indium tin oxide nanoparticles, nonradiative auger recombination of biexciton of the quantum dot is effectively inhibited, and two-photon radiation of the single quantum dot is realized.

The invention provides a null information leakage quantum dialogue protocol with collective retreat phase noise resistance. According to the protocol, logical quantum bit with noise interference invariance resistance of a decoherence-free subspace is utilized for eliminating noise effect, and two legal users secretly share initial state of each logic quantum bit by directly transferring corresponding auxiliary logic quantum bit to overcome the problem of information leakage. In the protocol of the invention, secret information is encoded in the initial logic quantum bit by two composite unitary operation. In addition, decoding only needs single-photon measurement rather than Bell state measurement or complex measurement so that the protocol is easy to execute. Security analysis shows that a plurality of active attacks of Eve can be effectively overcome, such as interception-retransmission attack, measurement-retransmission attack, entanglement-measurement attack and control non-operating attack. In addition, compared with anti-noise quantum dialogue protocols of Yang and Hwang, the null information leakage quantum dialogue protocol has better performance on quantum resource and quantum measurement.

The invention provides a cascading quantum time synchronization method. The method comprises the steps of: arranging a plurality of cascading stations in front of two stations needing time synchronization to form a cascading system, wherein the distance between every two adjacent stations does not exceed the action distance of quantum time synchronization; arranging a quantum light source and a quantum measurement device on each station to obtain photon arrival time between adjacent stations; based on a bidirectional time synchronization principle and a cross-correlation algorithm between frequency entangled two photons, calculating to obtain a clock difference between time frequency sources at the two ends of the cascade system by utilizing a photon arrival time sequence recorded by eachstation; and finally, adjusting the output time of the to-be-synchronized end by utilizing the measured clock error to realize time synchronization of the to-be-synchronized end and the source end. Onthe basis of fully utilizing the advantages of high accuracy and high stability of quantum time synchronization, the application distance of the quantum time synchronization is greatly expanded, so that the high-precision quantum time synchronization technology further meets the requirements of long-distance and high-precision time synchronization and transmission.

The invention belongs to the field of quantum measurement and control, and specifically discloses a threshold straight line determination method and device based on a measurement track. The thresholdstraight line determination method comprises the following steps: obtaining measurement data of a quantum bit reading signal when a quantum bit is in a determined quantum state, and carrying out complex number transformation processing on the measurement data to obtain original data corresponding to the quantum bit reading signal when the quantum bit is in the determined quantum state; obtaining ameasurement track corresponding to the quantum bit reading signal according to the original data; obtaining a first type of coordinate point data, a first statistical center coordinate point, a second type of coordinate point data and a second statistical center coordinate point according to the measurement track; and determining a threshold straight line according to the first type of coordinatepoint data, the first statistical center coordinate point, the second type of coordinate point data and the second statistical center coordinate point. The threshold straight line determination method can improve the data preprocessing precision and the obtained threshold linear precision, and can improve the reliability and the stability of the quantum computing system.

The invention discloses a method and a system for optimizing a goods loading three-dimensional layout based on a quantum genetic algorithm and belongs to an intelligent loading optimizing method. The method mainly comprises the following nine steps: inputting information about counters and packing boxes, initiating, calculating suitability, mutating, crossing, measuring quanta, optimally retaining, selecting a wheel disc, judging terminal conditions and outputting an optimizing result. The variety of genetic population genes is effectively increased through the combination of quantum calculation and the genetic algorithm, and the maintenance capacity and the overall optimizing capacity of the system are accordingly improved, so that a more accurately optimizing result about the goods three-dimensional layout is obtained. Meanwhile, the operation steps of the method provided by the invention for optimizing the goods loading three-dimensional layout based on the quantum genetic algorithm are clearer than those of the traditional algorithm. The method and the system can be used for electronic fine management over all kinds of warehouse logistics industries and can be applied in a wide range.

The invention discloses a quantum control remote joint implementation method, which belongs to the field of quantum, and is characterized in that three senders share quantum control information needing to be executed, and remote quantum control is completed in a joint assistance manner. The method of the invention adopts an easy-prepared, anti-noise five-particle entangled state as a quantum entangled channel to realize joint control of quantum states; a sender selects to execute corresponding single event measurement according to known remote quantum control information needing to be executedand measurement results of other communication parties, and a receiver executes local unitary operation on other particles according to measurement results of all the senders, so that a target statecan be prepared on the other particles. According to the invention, quantum communication and quantum measurement technologies are utilized to realize quantum state remote joint control. The method has the advantages of high feasibility and high safety.

The invention provides a quantum dialogue protocol with collective-dephasing noise resisting robustness based on logic qubits and CNOT operation. A preparation party produces the logic qubits serving as a transmission state to resist collective-dephasing noise. The other party knows the initial preparation state of the logic qubits by the aid of the CNOT operation and acquires secret information of the preparation party through decoding with the help of a classic information sequence transmitted by the preparation party. The preparation party reads secret information of the other party by the aid of quantum secure direct communication. In this way, the risk of information leakage is effectively avoided. In the protocol, only single-photon measurement is required for quantum measurement. Compared with a noise-resistant quantum dialogue protocol in the past, the protocol has the highest information theory efficiency. Compared with the recent quantum dialogue protocol that two adjacent logic qubits need to be prepared to be in the same quantum state, the protocol is easier to execute experimentally because the protocol does not have the special request.

The present invention belongs to the technical field of quantum measurement and control, and especially relates to a quantum bit frequency calibration method based on a Ramsey interference experiment.The method comprises the steps of: performing N-times Ramsey interference experiment for quantum bits, recording f0(f<N>d) obtained according to a result of each Ramsey interference experiment, and performing liner fitting of coordinate points formed by N f<N>d and the corresponding f0(f<N>d) in an orthogonal plane coordinate system to obtain a fitting linear equation; and according to the fitting linear equation, obtaining a fd value. The quantum bit frequency calibration method can effectively ensure the precision of the finally obtained quantum bit frequency calibration value by means of the Ramsey interference experiment and the data fitting.

The invention discloses a bright squeezed light field producing device. The bright squeezed light field producing device is characterized by being provided with an inner-cavity coherent population trapping (CPT) effect system, the inner-cavity CPT effect system is provided with a first light source and a second light source, the first light source is a bright squeezed laser source, and the secondlight source is a coherent laser source. The inner-cavity CPT effect system is provided with double resonant optical resonators, and artificial atoms are built in the double resonant optical resonators. The first light source and the second light source are simultaneously resonant with the optical resonators and produce a resonance effect with two transition energy levels of the artificial atoms to form a Lambda type three-energy-level structure, an inner-cavity CPT effect is achieved, conversion from quantum compression characteristics of the first light source to the second light source is completed, and preparation of a bright squeezed light field is achieved. The bright squeezed light field producing device is compact in structure and easy to operate, other different wavelengths of squeezed light can be prepared based on existing squeezed light, accordingly the wavelength range of the squeezed light is widened, and the bright squeezed light field producing device has the importantapplication value in the fields such as precision quantum measurement and quantum communication.

The invention belongs to the field of quantum measurement and control, and particularly relates to a method and device for obtaining a quantum state discrimination model, and the method comprises thesteps: obtaining first measurement data and second measurement data which are respectively corresponding to a quantum bit in a first quantum state and a second quantum state; processing the first measurement data and the second measurement data based on a two-dimensional Gaussian mixture model to obtain first quantum state label data and second quantum state label data which reflect the real distribution characteristics of the first quantum state and the second quantum state respectively; and training the first quantum state label data and the second quantum state label data to obtain a discrimination model for discriminating a quantum state type. According to the invention, the accuracy of the obtained discrimination model and the accuracy of the quantum state judgment result can be improved.

The invention discloses the polarization system of diamond color center nucleuses. The system comprises an optical control system, a microwave control system, a magnetic field control system and a control and data acquisition system. The optical control system, the microwave control system and the magnetic field control system are independent and are connected through the control and data acquisition system and a correlation component so as to form a diamond color center nucleus polarization system. Through the method of using a laser, a microwave, a magnetic field and a radio-frequency multi-physics field to act on a diamond according to a design sequence, interaction between a diamond color center and surrounding nucleuses can be high-sensitively and rapidly reduced, the high polarization efficiency of the nucleuses can be realized, de-coherence time used for quantum measurement can be prolonged, and support is provided for the technologies of quantum calculating, quantum sensing, quantum transmission and the like based on the diamond color center.

Two dimensional (2D) optical spectroscopy, wherein the spectrum has an excitation and an emission axis, reveals information formerly hidden in one-dimensional (1D) optical spectroscopy. However, current two dimensional optical spectroscopy systems are complex laboratory arrangements and accordingly limited in deployment. According to embodiments of the invention a monolithic platform providing significantly reduced complexity and increased robustness is provided allowing for “black-box” modules allowing commercial deployment of 2D optical spectroscopy instruments. Additionally, the invention supports high pulse repetition rates as well as one quantum and two quantum measurements under electronic control.

A recording method that records information in soliton units, a computing method that performs a computation, an information transmission method, an energy storage method, a magnetic flux measurement method and a quantum bit constitution method utilize the properties of phase solitons manifested between superconducting order parameters present in multiple bands in a superconductor having a multiple bands. The phase difference soliton is maintained, so information can be stored in the form of phase differences. Moreover, −Θsoliton phase slip will also be present when the same energy is carried in the reverse direction, so the soliton itself can have a + or − sign. The soliton enables storage of energy not accompanied by magnetic flux. Also, with soliton units, magnetic flux can be measured with greater precision by discriminating external magnetic flux. Moreover, using solitons and anti-solitons makes it possible to constitute quantum bits required in quantum measurements.