Hybrid entangled states(HESs),which involve different particles with various degrees of freedom,have garnered significant attention and been applied in a wide range of quantum technologies.However,similar to other cat...Hybrid entangled states(HESs),which involve different particles with various degrees of freedom,have garnered significant attention and been applied in a wide range of quantum technologies.However,similar to other categories of entanglement,maximally HESs inevitably degrade to mixed states due to the environmental noise and operational imperfections.To address the degradation problem,measurement-based entanglement purification offers a feasible and robust solution alternative to conventional gate-based purification methods.In this paper,we propose a measurement-based hybrid entanglement purification protocol(MB-HEPP)for a certain kind of HES which consists of polarization photons and coherent states.We extend our methodology to several conditions,such as the multi-copy and multi-party scenarios,and the photon-loss condition.Compared with previous HEPPs,this protocol has several advantages.First,it does not depend on post-selection and the purified HESs can be retained for further application.Second,it does not require the Bell state measurement,but only uses the parity check with conventional linear optical elements,which makes it have the higher success probability and more feasible.Our MB-HEPP has potential applications in future heterogeneous quantum networks.展开更多
Spectrum sensing is one of the key technologies in Cognitive Radios(CRs).Previous works are accomplished under simple channel models,which may lead to unreliable results when it applied to the over-the-air systems.In ...Spectrum sensing is one of the key technologies in Cognitive Radios(CRs).Previous works are accomplished under simple channel models,which may lead to unreliable results when it applied to the over-the-air systems.In this paper,we investigate the performance of a Multi-Resolution Spectrum Sensing(MRSS) algorithm under measurement-based channel models in China.MRSS is a wavelet based algorithm which is suitable for non-stationary,wideband signal analysis.Using statistical mod-eling,measurement-based channel models are presented under typical urban and suburban scenarios in Shanghai,China.Then,the performance of the MRSS algorithm is evaluated under the measure-ment-based channel models.Simulation results show that,using MRSS,the performance is always better in the scenarios where Line-Of-Sight(LOS) path exist;also,in LOS scenarios,rich scattering effect helps to increase the performance.展开更多
A new measurement-based admission control algorithm to support Quality of Service(QoS) demand is proposed for soft real-time applications. In the algorithm, admission test is performed across Multiple Time-Scales (MTS...A new measurement-based admission control algorithm to support Quality of Service(QoS) demand is proposed for soft real-time applications. In the algorithm, admission test is performed across Multiple Time-Scales (MTS) to accurately capture traffic fluctuation on various time-scales. By applying the QoS requirements directly to admission test, the MTS algorithm can properly meet the QoS target and maximize the bandwidth utilization.展开更多
Load model is one of the most important elements in power system operation and control.However,owing to its complexity,load modeling is still an open and very difficult problem.Summarizing our work on measurement-base...Load model is one of the most important elements in power system operation and control.However,owing to its complexity,load modeling is still an open and very difficult problem.Summarizing our work on measurement-based load modeling in China for more than twenty years,this paper systematically introduces the mathematical theory and applications regarding the load modeling.The flow chart and algorithms for measurement-based load modeling are presented.A composite load model structure with 13 parameters is also proposed.Analysis results based on the trajectory sensitivity theory indicate the importance of the load model pa-rameters for the identification.Case studies show the accuracy of the presented measurement-based load model.The load model thus built has been validated by field measurements all over China.Future working directions on measurement-based load modeling are also discussed in the paper.展开更多
The entangled coherent states(ECSs)have been widely used to realize quantum information processing tasks.However,the ECSs may suffer from photon loss and decoherence due to the inherent noise in quantum channel,which ...The entangled coherent states(ECSs)have been widely used to realize quantum information processing tasks.However,the ECSs may suffer from photon loss and decoherence due to the inherent noise in quantum channel,which may degrade the fidelity of ECSs.To overcome these obstacles,we present a measurement-based entanglement purification protocol(MBEPP)for ECSs to distill some highquality ECSs from a large number of low-quality copies.We first show the principle of this MBEPP without considering the photon loss.After that,we prove that this MBEPP is feasible to correct the error resulted from the photon loss.Additionally,this MBEPP only requires to operate the Bell state measurement without performing local two-qubit gates on the noisy pairs and the purified high-quality ECSs can be preserved for other applications.This MBEPP may have application potential in the implementation of long-distance quantum communication.展开更多
Measurement-based feedback has been adopted as an efficient cooling scheme capable of suppressing the thermal fluctuation of a mechanical resonator to a level limited by measurement imprecision.We present a scheme of ...Measurement-based feedback has been adopted as an efficient cooling scheme capable of suppressing the thermal fluctuation of a mechanical resonator to a level limited by measurement imprecision.We present a scheme of squeezed cooling in which the limit of feedback cooling imposed by the measurement imprecision is surpassed by parametrically squeezing the mechanical resonator in a periodically oscillating optical trap.To stabilize the parametrically amplified quadrature and simultaneously optimize the cooling for the squeezed quadrature,a measurement-based vector feedback capable of independently controlling the orthogonal motional quadrature is implemented.Our experiment demonstrates that the optimal condition for the squeezed cooling closely depends on the strength of squeezing.With the ability to keep the orthogonal quadrature well decoupled,optimal squeezed cooling of the mechanical resonator under strong squeezing is achieved with the squeezed variance becoming 8.1 dB below the limit of feedback cooling and the creation of a 31.7 dB thermomechanical squeezed cooling.Although this research is conducted in the classical regime,the scheme of squeezed cooling can be naturally extended to quantum systems with the prospects of creating quantum squeezing of a room-temperature mechanical resonator and enabling displacement measurement beyond the standard quantum limit.展开更多
Early warning of impending instability in a power system under disturbance conditions is important for preventing of system collapse.A measurement-based approach is proposed to assess the potential power system transi...Early warning of impending instability in a power system under disturbance conditions is important for preventing of system collapse.A measurement-based approach is proposed to assess the potential power system transient instability problem under cascading outages.Where a measurement-based index is obtained as the estimation accuracy of a linear autoregressive exogenous(ARX)model to estimate the dynamic response of the power system and indicate the system stability to some extent after a disturbance.The proposed approach was verified using a set of marginally stable cases in a 179-bus WECC equivalent power system.Then the instability early warning threshold for this system is obtained as 0.44.展开更多
This paper presents an approach to design proportional-integral-derivative controllers for inductionmachines usingmeasurements.Most controlmethods developed for induc-tion machines are generally based on mathematical ...This paper presents an approach to design proportional-integral-derivative controllers for inductionmachines usingmeasurements.Most controlmethods developed for induc-tion machines are generally based on mathematical models.Due to complex dynamics of induction machines,identified models are often unable to perfectly describe their behaviour.Thus,the system performance will be limited by the quality of the identified model.Hence,developing control methods that do not require the availability of system model is advantageous.Here,we propose an approach that uses the frequency response data to directly design controllers.The main idea here is to find controller parameters so that the closed-loop frequency response fits a desired frequency response.Its main advantage is that errors associated with the modelling process are avoided.Moreover,the control design process does not depend on the order and complexity of the plant.A practical application to induction machines illustrates the efficacy of the proposed approach.展开更多
One-way quantum computation focuses on initially generating an entangled cluster state followed by a sequence of measurements with classical communication of their individual outcomes.Recently,a delayed-measurement ap...One-way quantum computation focuses on initially generating an entangled cluster state followed by a sequence of measurements with classical communication of their individual outcomes.Recently,a delayed-measurement approach has been applied to replace classical communication of individual measurement outcomes.In this work,by considering the delayed-measurement approach,we demonstrate a modified one-way CNOT gate using the on-cloud superconducting quantum computing platform:Quafu.The modified protocol for one-way quantum computing requires only three qubits rather than the four used in the standard protocol.Since this modified cluster state decreases the number of physical qubits required to implement one-way computation,both the scalability and complexity of the computing process are improved.Compared to previous work,this modified one-way CNOT gate is superior to the standard one in both fidelity and resource requirements.We have also numerically compared the behavior of standard and modified methods in large-scale one-way quantum computing.Our results suggest that in a noisy intermediate-scale quantum(NISQ)era,the modified method shows a significant advantage for one-way quantum computation.展开更多
Measurement-based quantum computation in an optical setup shows great promise towards the implementation oflarge-scale quantum computation. The difficulty of measurement-based quantum computation lies in the preparati...Measurement-based quantum computation in an optical setup shows great promise towards the implementation oflarge-scale quantum computation. The difficulty of measurement-based quantum computation lies in the preparation ofcluster state. In this paper, we propose the method of generating the large-scale cluster state, which is a platform formeasurement-based quantum computation. In order to achieve more complex quantum circuits, the preparation protocolof N-photon cluster state will be proposed as a generalization of the preparation of four- and five-photon cluster states.Furthermore, our proposal is experimentally feasible.展开更多
In blind quantum computation(BQC),a client with weak quantum computation capabilities is allowed to delegate its quantum computation tasks to a server with powerful quantum computation capabilities,and the inputs,algo...In blind quantum computation(BQC),a client with weak quantum computation capabilities is allowed to delegate its quantum computation tasks to a server with powerful quantum computation capabilities,and the inputs,algorithms and outputs of the quantum computation are confidential to the server.Verifiability refers to the ability of the client to verify with a certain probability whether the server has executed the protocol correctly and can be realized by introducing trap qubits into the computation graph state to detect server deception.The existing verifiable universal BQC protocols are analyzed and compared in detail.The XTH protocol(proposed by Xu Q S,Tan X Q,Huang R in 2020),a recent improvement protocol of verifiable universal BQC,uses a sandglass-like graph state to further decrease resource expenditure and enhance verification capability.However,the XTH protocol has two shortcomings:limitations in the coloring scheme and a high probability of accepting an incorrect computation result.In this paper,we present an improved version of the XTH protocol,which revises the limitations of the original coloring scheme and further improves the verification ability.The analysis demonstrates that the resource expenditure is the same as for the XTH protocol,while the probability of accepting the wrong computation result is reduced from the original minimum(0.866)^(d*)to(0.819)^(d^(*)),where d;is the number of repeated executions of the protocol.展开更多
Constant traffic congestion consumes enormous amounts of energy and causes vastly increased journey times. Therefore, real-time traffic information is of great importance to the public because such information is inva...Constant traffic congestion consumes enormous amounts of energy and causes vastly increased journey times. Therefore, real-time traffic information is of great importance to the public because such information is invaluable to more efficient traffic control and travel planning. To obtain such information in metropolises like Shanghai, however, is very challenging due to the extraordinarily large scale and com- plexity of the underlying road network. In this paper, we pro- pose a novel traffic estimation scheme utilizing surveillance cameras pervasively deployed in cities. With only a limited number of roads with cameras, we adopt a measurement- based traffic matrix （TM） estimation method to infer the traf- fic conditions on those roads with no cameras. Extensively trace-driven simulations as well as field study results show that our scheme can achieve high accuracy with a very limited number of measurements. The accuracy of our measurement- based algorithm outperforms the traditional speed-based and model-based approaches by up to 50%.展开更多
To address the difculty of obtaining Guide to the Expression of Uncertainty in Measurement(GUM)-based measurement uncertainty for sensors employing artifcial neural networks(ANNs)in the feld of mechanical measurement,...To address the difculty of obtaining Guide to the Expression of Uncertainty in Measurement(GUM)-based measurement uncertainty for sensors employing artifcial neural networks(ANNs)in the feld of mechanical measurement,this paper proposes and demonstrates a GUM-based uncertainty evaluation method for a nonlinear optical angle sensor that uses a multilayer perceptron artifcial neural network(MLP-ANN).The proposed sensor decodes the angular information of a target by inputting a measured second harmonic generation spectrum into a trained MLP-ANN to enable wide-range angle measurement.However,the measurement uncertainty of this method has not yet been evaluated,and such an analysis is essential to assess the accuracy and reliability of the sensor.This paper demonstrates the measurement uncertainty evaluation of the nonlinear optical angle sensor using a specifcally trained MLP-ANN and thereby confrms the feasibility of the proposed GUM-based method.Mathematical derivations are provided to obtain the sensitivity coefcients required for uncertainty estimation.Notably,this derivation is one of the most challenging aspects when applying GUM to ANN-based sensors.The uncertainty of the reference instrument used to generate training labels is also considered by incorporating the efects of the ANN training.The proposed method reveals that the measurement uncertainty of the MLP-ANN estimation ranges from 0.555 arcseconds to 30.264 arcseconds across diferent measurement regions.A detailed discussion of the results is also provided.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12175106 and 92365110)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(Grant No.KYCX23-1028)。
文摘Hybrid entangled states(HESs),which involve different particles with various degrees of freedom,have garnered significant attention and been applied in a wide range of quantum technologies.However,similar to other categories of entanglement,maximally HESs inevitably degrade to mixed states due to the environmental noise and operational imperfections.To address the degradation problem,measurement-based entanglement purification offers a feasible and robust solution alternative to conventional gate-based purification methods.In this paper,we propose a measurement-based hybrid entanglement purification protocol(MB-HEPP)for a certain kind of HES which consists of polarization photons and coherent states.We extend our methodology to several conditions,such as the multi-copy and multi-party scenarios,and the photon-loss condition.Compared with previous HEPPs,this protocol has several advantages.First,it does not depend on post-selection and the purified HESs can be retained for further application.Second,it does not require the Bell state measurement,but only uses the parity check with conventional linear optical elements,which makes it have the higher success probability and more feasible.Our MB-HEPP has potential applications in future heterogeneous quantum networks.
基金Supported by the National Major R&D Program of China (No. 2009ZX03003-008)
文摘Spectrum sensing is one of the key technologies in Cognitive Radios(CRs).Previous works are accomplished under simple channel models,which may lead to unreliable results when it applied to the over-the-air systems.In this paper,we investigate the performance of a Multi-Resolution Spectrum Sensing(MRSS) algorithm under measurement-based channel models in China.MRSS is a wavelet based algorithm which is suitable for non-stationary,wideband signal analysis.Using statistical mod-eling,measurement-based channel models are presented under typical urban and suburban scenarios in Shanghai,China.Then,the performance of the MRSS algorithm is evaluated under the measure-ment-based channel models.Simulation results show that,using MRSS,the performance is always better in the scenarios where Line-Of-Sight(LOS) path exist;also,in LOS scenarios,rich scattering effect helps to increase the performance.
文摘A new measurement-based admission control algorithm to support Quality of Service(QoS) demand is proposed for soft real-time applications. In the algorithm, admission test is performed across Multiple Time-Scales (MTS) to accurately capture traffic fluctuation on various time-scales. By applying the QoS requirements directly to admission test, the MTS algorithm can properly meet the QoS target and maximize the bandwidth utilization.
基金Supported in part by the Chinese National Key Basic Research Special Fund(Grant No.2004CB217901)the National Natural Science Foundation of China(Grant No.50595410)by the Program for Changjiang Scholars and Innovative Research Team in University under IRT0515
文摘Load model is one of the most important elements in power system operation and control.However,owing to its complexity,load modeling is still an open and very difficult problem.Summarizing our work on measurement-based load modeling in China for more than twenty years,this paper systematically introduces the mathematical theory and applications regarding the load modeling.The flow chart and algorithms for measurement-based load modeling are presented.A composite load model structure with 13 parameters is also proposed.Analysis results based on the trajectory sensitivity theory indicate the importance of the load model pa-rameters for the identification.Case studies show the accuracy of the presented measurement-based load model.The load model thus built has been validated by field measurements all over China.Future working directions on measurement-based load modeling are also discussed in the paper.
基金supported by the National Natural Science Foundation of China under Grant No.11974189the Postgraduate Research&Practice Innovation Program of Jiangsu Province under Grant No.KYCX20-0731.
文摘The entangled coherent states(ECSs)have been widely used to realize quantum information processing tasks.However,the ECSs may suffer from photon loss and decoherence due to the inherent noise in quantum channel,which may degrade the fidelity of ECSs.To overcome these obstacles,we present a measurement-based entanglement purification protocol(MBEPP)for ECSs to distill some highquality ECSs from a large number of low-quality copies.We first show the principle of this MBEPP without considering the photon loss.After that,we prove that this MBEPP is feasible to correct the error resulted from the photon loss.Additionally,this MBEPP only requires to operate the Bell state measurement without performing local two-qubit gates on the noisy pairs and the purified high-quality ECSs can be preserved for other applications.This MBEPP may have application potential in the implementation of long-distance quantum communication.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2130117,12074030,12274107,U1930403,U1930402 and 12088101)the Natural Science Foundation of Hubei Province(Grant No.2020CFB830)the Research Funds of Hainan University(Grant Nos.KYQD(ZR)22170,and KYQD(ZR)23010)。
文摘Measurement-based feedback has been adopted as an efficient cooling scheme capable of suppressing the thermal fluctuation of a mechanical resonator to a level limited by measurement imprecision.We present a scheme of squeezed cooling in which the limit of feedback cooling imposed by the measurement imprecision is surpassed by parametrically squeezing the mechanical resonator in a periodically oscillating optical trap.To stabilize the parametrically amplified quadrature and simultaneously optimize the cooling for the squeezed quadrature,a measurement-based vector feedback capable of independently controlling the orthogonal motional quadrature is implemented.Our experiment demonstrates that the optimal condition for the squeezed cooling closely depends on the strength of squeezing.With the ability to keep the orthogonal quadrature well decoupled,optimal squeezed cooling of the mechanical resonator under strong squeezing is achieved with the squeezed variance becoming 8.1 dB below the limit of feedback cooling and the creation of a 31.7 dB thermomechanical squeezed cooling.Although this research is conducted in the classical regime,the scheme of squeezed cooling can be naturally extended to quantum systems with the prospects of creating quantum squeezing of a room-temperature mechanical resonator and enabling displacement measurement beyond the standard quantum limit.
基金supported by Electric Power Research Institute and also made use of Engineering Research Center Shared Facilities supported by the DOE under NSF Award Number EEC1041877 and the CURENT Industry Partnership Program.
文摘Early warning of impending instability in a power system under disturbance conditions is important for preventing of system collapse.A measurement-based approach is proposed to assess the potential power system transient instability problem under cascading outages.Where a measurement-based index is obtained as the estimation accuracy of a linear autoregressive exogenous(ARX)model to estimate the dynamic response of the power system and indicate the system stability to some extent after a disturbance.The proposed approach was verified using a set of marginally stable cases in a 179-bus WECC equivalent power system.Then the instability early warning threshold for this system is obtained as 0.44.
基金NPRP grant NPRP09-1153-2-450 from the Qatar National Research Fund(a member of Qatar Foundation).
文摘This paper presents an approach to design proportional-integral-derivative controllers for inductionmachines usingmeasurements.Most controlmethods developed for induc-tion machines are generally based on mathematical models.Due to complex dynamics of induction machines,identified models are often unable to perfectly describe their behaviour.Thus,the system performance will be limited by the quality of the identified model.Hence,developing control methods that do not require the availability of system model is advantageous.Here,we propose an approach that uses the frequency response data to directly design controllers.The main idea here is to find controller parameters so that the closed-loop frequency response fits a desired frequency response.Its main advantage is that errors associated with the modelling process are avoided.Moreover,the control design process does not depend on the order and complexity of the plant.A practical application to induction machines illustrates the efficacy of the proposed approach.
基金the valuable discussions.Project supported by the National Natural Science Foundation of China(Grant Nos.92265207 and T2121001)Beijing Natural Science Foundation(Grant No.Z200009).
文摘One-way quantum computation focuses on initially generating an entangled cluster state followed by a sequence of measurements with classical communication of their individual outcomes.Recently,a delayed-measurement approach has been applied to replace classical communication of individual measurement outcomes.In this work,by considering the delayed-measurement approach,we demonstrate a modified one-way CNOT gate using the on-cloud superconducting quantum computing platform:Quafu.The modified protocol for one-way quantum computing requires only three qubits rather than the four used in the standard protocol.Since this modified cluster state decreases the number of physical qubits required to implement one-way computation,both the scalability and complexity of the computing process are improved.Compared to previous work,this modified one-way CNOT gate is superior to the standard one in both fidelity and resource requirements.We have also numerically compared the behavior of standard and modified methods in large-scale one-way quantum computing.Our results suggest that in a noisy intermediate-scale quantum(NISQ)era,the modified method shows a significant advantage for one-way quantum computation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12025401 and U1930402).
文摘Measurement-based quantum computation in an optical setup shows great promise towards the implementation oflarge-scale quantum computation. The difficulty of measurement-based quantum computation lies in the preparation ofcluster state. In this paper, we propose the method of generating the large-scale cluster state, which is a platform formeasurement-based quantum computation. In order to achieve more complex quantum circuits, the preparation protocolof N-photon cluster state will be proposed as a generalization of the preparation of four- and five-photon cluster states.Furthermore, our proposal is experimentally feasible.
文摘In blind quantum computation(BQC),a client with weak quantum computation capabilities is allowed to delegate its quantum computation tasks to a server with powerful quantum computation capabilities,and the inputs,algorithms and outputs of the quantum computation are confidential to the server.Verifiability refers to the ability of the client to verify with a certain probability whether the server has executed the protocol correctly and can be realized by introducing trap qubits into the computation graph state to detect server deception.The existing verifiable universal BQC protocols are analyzed and compared in detail.The XTH protocol(proposed by Xu Q S,Tan X Q,Huang R in 2020),a recent improvement protocol of verifiable universal BQC,uses a sandglass-like graph state to further decrease resource expenditure and enhance verification capability.However,the XTH protocol has two shortcomings:limitations in the coloring scheme and a high probability of accepting an incorrect computation result.In this paper,we present an improved version of the XTH protocol,which revises the limitations of the original coloring scheme and further improves the verification ability.The analysis demonstrates that the resource expenditure is the same as for the XTH protocol,while the probability of accepting the wrong computation result is reduced from the original minimum(0.866)^(d*)to(0.819)^(d^(*)),where d;is the number of repeated executions of the protocol.
文摘Constant traffic congestion consumes enormous amounts of energy and causes vastly increased journey times. Therefore, real-time traffic information is of great importance to the public because such information is invaluable to more efficient traffic control and travel planning. To obtain such information in metropolises like Shanghai, however, is very challenging due to the extraordinarily large scale and com- plexity of the underlying road network. In this paper, we pro- pose a novel traffic estimation scheme utilizing surveillance cameras pervasively deployed in cities. With only a limited number of roads with cameras, we adopt a measurement- based traffic matrix （TM） estimation method to infer the traf- fic conditions on those roads with no cameras. Extensively trace-driven simulations as well as field study results show that our scheme can achieve high accuracy with a very limited number of measurements. The accuracy of our measurement- based algorithm outperforms the traditional speed-based and model-based approaches by up to 50%.
基金supported by the Japan Society for the Promotion of Science(JP24K00771)Japan Science and Technology Agency(J220000798)。
文摘To address the difculty of obtaining Guide to the Expression of Uncertainty in Measurement(GUM)-based measurement uncertainty for sensors employing artifcial neural networks(ANNs)in the feld of mechanical measurement,this paper proposes and demonstrates a GUM-based uncertainty evaluation method for a nonlinear optical angle sensor that uses a multilayer perceptron artifcial neural network(MLP-ANN).The proposed sensor decodes the angular information of a target by inputting a measured second harmonic generation spectrum into a trained MLP-ANN to enable wide-range angle measurement.However,the measurement uncertainty of this method has not yet been evaluated,and such an analysis is essential to assess the accuracy and reliability of the sensor.This paper demonstrates the measurement uncertainty evaluation of the nonlinear optical angle sensor using a specifcally trained MLP-ANN and thereby confrms the feasibility of the proposed GUM-based method.Mathematical derivations are provided to obtain the sensitivity coefcients required for uncertainty estimation.Notably,this derivation is one of the most challenging aspects when applying GUM to ANN-based sensors.The uncertainty of the reference instrument used to generate training labels is also considered by incorporating the efects of the ANN training.The proposed method reveals that the measurement uncertainty of the MLP-ANN estimation ranges from 0.555 arcseconds to 30.264 arcseconds across diferent measurement regions.A detailed discussion of the results is also provided.
