检索结果-南通市图书馆

A new maximum-likelihood phase estimation method for X-ray pulsar signals

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第6期15卷 458-469页

作者： Hua ZHANG Lu-ping XU Yang-he SHEN Rong JIAO Jing-rong SUN School of Aerospace Science and Technology Xidian University

X-ray pulsar navigation(XPNAV) is an attractive method for autonomous navigation of deep space in the future. Currently, techniques for estimating the phase of X-ray pulsar radiation involve the maximization of the general non-convex object functions based on the average profile from the epoch folding method. This results in the suppression of useful information and highly complex computation. In this paper, a new maximum likelihood(ML) phase estimation method that directly utilizes the measured time of arrivals(TOAs) is presented. The X-ray pulsar radiation will be treated as a cyclo-stationary process and the TOAs of the photons in a period will be redefined as a new process, whose probability distribution function is the normalized standard profile of the pulsar. We demonstrate that the new process is equivalent to the generally used Poisson model. Then, the phase estimation problem is recast as a cyclic shift parameter estimation under the ML estimation, and we also put forward a parallel ML estimation method to improve the ML solution. Numerical simulation results show that the estimator described here presents a higher precision and reduces the computational complexity compared with currently used estimators.

关键词： X-ray pulsar Poisson model phase estimation Maximum likelihood

A phase estimation Algorithm for Quantum Speed-Up Multi-Party Computing

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第4期67卷 241-252页

作者： Wenbin Yu Hao Feng Yinsong Xu Na Yin Yadang Chen Zhi-Xin Yang Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Jiangsu Engineering Center of Network MonitoringSchool of Computer and SoftwareNanjing University of Information Science&TechnologyNanjing210044China Department of Computer Science and Engineering Michigan State UniversityEast Lansing48824MIUSA State Key Laboratory of Internet of Things for Smart City and Department of Electromechanical Engineering University of Macao999078Macao

Security and privacy issues have attracted the attention of researchers in the field of IoT as the information processing scale grows in sensor *** computing,theoretically known as an absolutely secure way to store and transmit information as well as a speed-up way to accelerate local or distributed classical algorithms that are hard to solve with polynomial complexity in computation or *** this paper,we focus on the phase estimation method that is crucial to the realization of a general multi-party computing model,which is able to be accelerated by quantum algorithms.A novel multi-party phase estimation algorithm and the related quantum circuit are proposed by using a distributed Oracle operator with *** proved theoretical communication complexity of this algorithm shows it can give the phase estimation before applying multi-party computing efficiently without increasing any additional ***,a practical problem of multi-party dating investigated shows it can make a successful estimation of the number of solution in advance with zero communication complexity by utilizing its special statistic *** simulations present the correctness,validity and efficiency of the proposed estimation method.

关键词： Edge computing security multi-party computing quantum algorithm phase estimation communication complexity

A Direct phase estimation Method of X-ray Pulsar Signal Without Epoch Folding

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Direct Phase Estimation Method of X-ray Pulsar Signal With...

MAP Pulse phase estimation of X-ray Pulsars

第五届中国卫星导航学术年会

作者： Hua ZHANG Lu-ping XU Rong JIAO Yang-He SHEN Jing-Rong SUN School of Aerospace Science and Technology Xidian University

X-ray Pulsar Navigation（XPNAV） is an attractive method for the future deep space autonomous ***,techniques for the phase estimation of X-ray pulsar radiation involves maximization of generally non-convex object functions based on average profile from epoch folding method,which results in suppression of useful information and high *** this paper,a new maximum likelihood（ML） directly utilizing the measured Time of Arrivals（TOAs） is *** x-ray pulsar radiation will be traded as a cyclostationary process and the TOAs of the photons in a period will be redefined as a new process,whose probability distribution function is the normalized standard profile of the *** proved the new process is equivalent to the general used Poisson ***,the phase estimation problem is recast as a cyclic shift parameter estimation process under ML estimation,and we also put forwards a parallel ML estimation method to improve the ML ***,numerical simulation results show how the herein described estimator present a higher precision and reduced computation complexity compared with the current estimators.

关键词： X‐ray pulsar Poisson model phase estimation maximum likelihood

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

MAP Pulse Phase Estimation of X-ray Pulsars

Measuring small longitudinal phase shifts via weak measurement amplification

第三届中国卫星导航学术年会

作者： Zhang hua 1,2 , Xu Luping 1,2 , Feng Dajun 1,2 1 School of Electronic Engineering, Xidian University, Xi’an 710071, China 2 Institute of Astronautics and Aeronautics, Xidian University, Xi’an 710071, China

To bring in a priori information to improve the phase estimation for X-ray pulsar signals, the explicit structure of the approximate maximum a posteriori probability （MAP） estimator based on Bayes’ rule is derived. Tikhonov probability distribution function （pdf） is presented to model the a priori knowledge. The Time Of Arrival （TOA） of the individual photon is modeled as a random variable whose pdf is represented using the pulsar integrated profile, and the Gaussian fitting method is presented to express the profile analytical. Cramer-Rao lower bound （CRLB） on the mean-square error （mse） is obtained. The analysis and experiments show that the mse performance of the MAP estimator can approach the CRLB closely.

关键词： Pulsar MAP CRLB phase estimation

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第3期33卷 105-111页

作者：徐凯胡晓敏胡孟军王宁宁张超黄运锋柳必恒李传锋郭光灿张永生 CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China Beijing Academy of Quantum Information Sciences Beijing 100193China

Weak measurement amplification,which is considered as a very promising scheme in precision measurement,has been applied to various small physical quantities *** many physical quantities can be converted into phase signals,it is interesting and important to consider measuring small longitudinal phase shifts by using weak ***,we propose and experimentally demonstrate a novel weak measurement amplification-based small longitudinal phase estimation,which is suitable for polarization *** realize one order of magnitude amplification measurement of a small phase signal directly introduced by a liquid crystal variable retarder and show that it is robust to the imperfection of ***,we analyze the effect of magnification error which is never considered in the previous works,and find the constraint on the *** results may find important applications in high-precision measurements,e.g.,gravitational wave detection.

关键词： weak measurement phase estimation quantum optics

Fast period estimation of X-ray pulsar signals using an improved fast folding algorithm

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第10期36卷 309-316页

作者： Minzhang SONG Yidi WANG Wei ZHENG Liansheng LI Yusong WANG Xiaowei HU Yulong WU College of Aerospace Sciences and Engineering National University of Defense TechnologyChangsha 410073China Unit 71770 of PLA Taian 271000China Beijing Institute of Control Engineering Beijing 100076China

An accurate period is important to recover the pulse profile from a recorded photon event series of an X-ray pulsar and to estimate the pulse time of arrival,which is the measurement of X-ray pulsar *** folding is a classical period estimation method in the time domain;however,its computational complexity grows as the number of trail periods *** order to reduce the computational complexity,this paper improves the fast folding algorithm through segment correlation and amplitude accumulation,which is based on the post-order traversal of a binary *** with epoch folding,the improved fast folding algorithm can achieve a similar accuracy at the cost of a lower computational *** with the original fast folding algorithm,the improved algorithm can be applied to detectors with a much smaller effective *** performance of the method is investigated by simulation data and observation data from the Neutron star Interior Composition Explorer(NICER).

关键词： Epoch folding Fast folding algorithm Pulsar spin period phase estimation X-ray pulsar

在线全文

学校读者我要写书评

暂无评论

Quantum metrology

Chinese Physics B 2013年第11期22卷 91-100页

作者：项国勇郭光灿 Key Laboratory of Quantum Information University of Science and Technology of China

The statistical error is ineluctable in any measurement. Quantum techniques, especially with the development of quantum information, can help us squeeze the statistical error and enhance the precision of measurement. In a quantum system, there are some quantum parameters, such as the quantum state, quantum operator, and quantum dimension, which have no classical counterparts. So quantum metrology deals with not only the traditional parameters, but also the quantum parameters. Quantum metrology includes two important parts： measuring the physical parameters with a precision beating the classical physics limit and measuring the quantum parameters precisely. In this review, we will introduce how quantum characters （e.g., squeezed state and quantum entanglement） yield a higher precision, what the research areas are scientists most interesting in, and what the development status of quantum metrology and its perspectives are.

关键词： quantum entangled state phase estimation quantum imaging quantum tomography

Optimal phase sensitivity of atomic Ramsey interferometers with coherent spin states

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2011年第3期6卷 251-257页

作者： Guang-ri JIN Yong-chun LIU Li YOU Department of Physics Beijing Jiaotong University Beijing 100044 China Department of Physics Tsinghua University Beijing 100085 China

We present a detailed analysis of phase sensitivity for a nonlinear Ramsey interferometer, which utilize effective mean-field interaction of a two-component Bose-Einstein condensate in phase ac- cumulation. For large enough particle number N and small phase shift φ, analytical results of the Ramsey signal and the phase sensitivity are derived for a product coherent state θ, 0）. When collisional dephasing is absent, we confirm that the optimal sensitivity scales as 2/N3/2 for polar angle of the initial state θ = π/4 or 3π/4. The best-sensitivity phase satisfies different transcendental equations, depending upon the initial state and the observable being measured after the phase accumulation. In the presence of the collisional dephasing, we show that the N-3/2-scaling rule of the sensitivity maintains with spin operators jx and jy measurements. A slightly better sensitivity is attainable for optimal coherent state with θ = π/6 or 5π/6.

关键词： Ramsey interferometry phase estimation Bose-Einstein condensates phase decay,one-axis twisting model

Quantum information processing and metrology with color centers in diamonds

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2014年第5期9卷 587-597页

作者： Jing-Wei Zhou Peng-Fei Wang Fa-Zhan Shi Pu Huang Xi Kong Xiang-Kun Xu Qi Zhang Zi-Xiang Wang Xing Rong Jiang-Feng Du Hefei National Laboratory for Physics Sciences at the Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China

The Nitrogen Vacancy （NV） center is becoming a promising qubit for quantum information processing. The defect has a long coherence time at room temperature and it allows spin state initialized and read out by laser and manipulated by microwave pulses. It has been utilized as a ultra sensi- tive probe for magnetic fields and remote spins as well. Here, we review the recent progresses in experimental demonstrations based on NV centers. We first introduce our work on implementation of the Deutsch- Jozsa algorithm with a single electronic spin in diamond. Then the quantum nature of the bath around the center spin is revealed and continuous wave dynamical decoupling has been demonstrated. By applying dynamical decoupling, a multi-pass quantum metrology protocol is realized to enhance phase estimation. In the final, we demonstrated NV center can be regarded as a ultra-sensitive sensor spin to implement nuclear magnetic resonance （NMR） imaging at nanoscale.

关键词： quantum information processing and metrology Nitrogen Vacancy center phase estimation dynamical deeoupling single spin detection