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coherence Based Sufficient Condition for Support Recovery Using Generalized Orthogonal Matching Pursuit

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Computer Systems Science & Engineering 2023年第5期45卷 2049-2058页

作者： Aravindan Madhavan Yamuna Govindarajan Neelakandan Rajamohan Department of Electronics and Communication Engineering Annamalai UniversityChidambaram608002Tamil NaduIndia School of Electrical Sciences Indian Institute of TechnologyFarmgudiPondaGoaIndia

In an underdetermined system,compressive sensing can be used to recover the support vector.Greedy algorithms will recover the support vector indices in an iterative manner.Generalized Orthogonal Matching Pursuit(GOMP)is the generalized form of the Orthogonal Matching Pursuit(OMP)algorithm where a number of indices selected per iteration will be greater than or equal to 1.To recover the support vector of unknown signal‘x’from the compressed measurements,the restricted isometric property should be satisfied as a sufficient condition.Finding the restricted isometric constant is a non-deterministic polynomial-time hardness problem due to that the coherence of the sensing matrix can be used to derive the sufficient condition for support recovery.In this paper a sufficient condition based on the coherence parameter to recover the support vector indices of an unknown sparse signal‘x’using GOMP has been derived.The derived sufficient condition will recover support vectors of P-sparse signal within‘P’iterations.The recovery guarantee for GOMP is less restrictive,and applies to OMP when the number of selection elements equals one.Simulation shows the superior performance of the GOMP algorithm compared with other greedy algorithms.

关键词： Compressed sensing restricted isometric constant generalized orthogonal matching pursuit support recovery recovery guarantee coherence

Impact of distance between two hubs on the network coherence of tree networks

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信息与电子工程前沿:英文版 2023年第9期24卷 1349-1356页

作者： Daquan LI Weigang SUN Hongxiang HU School of Sciences Hangzhou Dianzi UniversityHangzhou 310018China

We study the impact of the distance between two hubs on network coherence defined by Laplacian eigenvalues.Network coherence is a measure of the extent of consensus in a linear system with additive noise.To obtain an exact determination of coherence based on the distance,we choose a family of tree networks with two hubs controlled by two parameters.Using the tree’s regular structure,we obtain analytical expressions of the coherences with regard to network parameters and the network size.We then demonstrate that a shorter distance and a larger difference in the degrees of the two hubs lead to a higher coherence.With the same network size and distance,the best coherence occurs in the tree with the largest difference in the hub’s degrees.Finally,we establish a correlation between network coherence and average path length and find that they behave linearly.

关键词： Consensus coherence Distance Average path length

Transformation relation between coherence and entanglement for two-qubit states

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Chinese Physics B 2023年第1期32卷 178-182页

作者：周晴云范小刚赵发王栋叶柳 School of Physics&Optoelectronics Engineering Anhui UniversityHefei 230601China

Entanglement and coherence are two important resources in quantum information theory. A question naturally arises:Is there some connection between them? We prove that the entanglement of formation and the first-order coherence of twoqubit states satisfy an inequality relation. Two-qubit pure state reaches the upper bound of this inequality. A large number of randomly generated states are used to intuitively verify the complementarity between the entanglement of formation and the first-order coherence. We give the maximum accessible coherence of two-qubit states. Our research results will provide a reliable theoretical basis for conversion of the two quantum resources.

关键词： entanglement coherence first-order coherence entanglement of formation

Bounds on positive operator-valued measure based coherence of superposition

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Chinese Physics B 2023年第5期32卷 228-234页

作者：郭梦丽梁津敏李波费少明王志玺 School of Mathematical Sciences Capital Normal UniversityBeijing 100048China School of Computer and Computing Science Hangzhou City UniversityHangzhou 310015China Max–Planck-Institute for Mathematics in the Sciences Leipzig 04103Germany

Quantum coherence is a fundamental feature of quantum physics and plays a significant role in quantum information processing.By generalizing the resource theory of coherence from von Neumann measurements to positive operatorvalued measures(POVMs),POVM-based coherence measures have been proposed with respect to the relative entropy of coherence,the l_(1) norm of coherence,the robustness of coherence and the Tsallis relative entropy of coherence.We derive analytically the lower and upper bounds on these POVM-based coherence of an arbitrary given superposed pure state in terms of the POVM-based coherence of the states in superposition.Our results can be used to estimate range of quantum coherence of superposed states.Detailed examples are presented to verify our analytical bounds.

关键词： coherence POVM-based coherence relative entropy l_(1)norm Tsallis relative entropy

Complementarity between quantum coherence and mixedness:a majorization approach

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Communications in Theoretical Physics 2023年第5期75卷 73-83页

作者： Yanet Alvarez Marcelo Losada Mariela Portesi Gustavo M Bosyk Instituto de Física La Plata CONICET–UNLP1900 La PlataArgentina Facultad de Ciencias Exactas Universidad Nacional de La Plata1900 La PlataArgentina Facultad de Matemática AstronomíaFísica y ComputaciónUniversidad Nacional de Córdoba5000 CórdobaArgentina

Quantum coherence is a relevant resource for various quantum information processing tasks,but it is fragile since it is generally affected by environmental noise.This is reflected in the loss of purity of the system,which in turn limits the amount of quantum coherence of it.As a consequence,a complementarity relation between coherence and mixedness arises.Previous works characterize this complementarity through inequalities between theℓ1-norm of coherence and linear entropy,and between the relative entropy of coherence and von Neumann entropy.However,coherence-mixedness complementarity is expected to be a general feature of quantum systems,regardless of the measures used.Here,an alternative approach to coherence-mixedness complementarity,based on majorization theory,is proposed.Vectorial quantifiers of coherence and mixedness,namely the coherence vector and the spectrum,respectively,are used,instead of scalar measures.A majorization relation for the tensor product of both vectorial quantifiers is obtained,capturing general aspects of the trade-off between coherence and mixedness.The optimal bound for qubit systems and numerical bounds for qutrit systems are analyzed.Finally,coherence-mixedness complementarity relations are derived for a family of symmetric,concave and additive functions.These results provide a deeper insight into the relation between quantum coherence and mixedness.

关键词： coherence mixedness complementarity majorization

coherence generation and population transfer in a three-level ladder system

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Chinese Physics B 2011年第5期20卷 54-60页

作者：张冰姜云王刚张理达吴金辉高锦岳 College of Physics Jilin University Key Laboratory of Coherent Light and Atomic and Molecular Spectroscopy of Educational Ministry College of Physics and Electronic Engineering Mudanjiang Teachers' College Heilongjiang Superhard Materials Key Laboratory

This work explores the effect of spontaneous emission on coherence generation and population transfer in a three- level ladder atomic system driven by two pulses in counterintuitive order. With adiabatic evolution and the weak- dephasing approximation, we find that a large coherence and population transfer can be achieved even with spontaneous decay rate. The maximum coherence and population transfer decrease with the increase of spontaneous decay rate from the highest state to intermediate state. But this effect can be compensated by shortening the pulse width and enlarging the delay time. Results show that the coherence generation and population transfer never depend on the spontaneous decay rate from the intermediate state to ground state. The validity of the analytic solution is examined by numerical calculation.

关键词： coherence population transfer spontaneous decay

Comparative study of self-compassion and sense of coherence in nurses of psychiatric hospitals

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Frontiers of Nursing 2023年第2期10卷 193-201页

作者： Iman Nosratabadi Golnaz Forough Ameri Sedigheh Iranmanesh Neda Asadi Nursing Research Center Kerman University of Medical SciencesKerman ***Iran Razi School of Nursing and Midwifery Kerman University of Medical SciencesKerman ***Iran

Objective:Nurses,due to the nature of their job,are subjected to various forms of stress and physical and psychological injuries.Self-compassion and a sense of coherence have attracted much attention in research in recent years as having high potential for improving the health and performance of people in the workplace.The present study aimed to compare self-compassion and the sense of coherence in nurses working in psychiatric hospitals and other hospitals of Kerman University of Medical Sciences.Methods:The present study was a descriptive-comparative study of applied type conducted on 100 nurses of Shahid Beheshti Psychiatric Hospital in Kerman by the census method and 100 nurses of other hospitals of Kerman University of Medical Sciences by the stratified random sampling method.The instruments included the self-compassion questionnaire and the sense of coherence questionnaire.Data were analyzed using the Statistical Package for Social Sciences software.Results:The results of the present study showed that self-compassion and sense of coherence were higher in psychiatric nurses(39.35±7.7 and 53.02±8.01)than among other nurses(36.03±5.81 and 49.76±6.30).There was a direct and moderate relationship between a sense of coherence and self-compassion(P-valuecoherence.Furthermore,the sense of coherence had a direct and weak relationship with all dimensions of self-compassion,except for the extreme imitation dimension,which showed a direct and moderate relationship to other dimensions(P-valuecoherence,as a form of self-communication,increase nurses’satisfaction and reduce nurses’job stress and,as a result,job performance is improved.

关键词： nurses psychiatric hospital self-compassion sense of coherence compassion coherence

Optical coherence tomography findings in chronic progressive external ophthalmoplegia

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Chinese Medical Journal 2019年第10期132卷 1202-1207页

作者： Yuan Wu Lei Kang Hai-Long Wu Yue Hou Zhao-Xia Wang Department of Ophthalmology Peking University First Hospital Beijing 100034 China Department of Neurology Peking University First Hospital Beijing 100034 China

Background: Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial encephalomyopathy caused by multiple mtDNA abnormalities. There is little information about the changes of ocular fundus with CPEO. The aim of this work was to measure and evaluate changes in the macular retinal thickness and optic nerve head in patients with CPEO using spectral-domain optical coherence tomography and to compare the findings with those of healthy individuals. Methods: Totally, 18 CPEO patients were enrolled in this study. Healthy volunteers matched for gender, age, and diopter settings were included as a control group. The retinal thickness of macular central fovea, inner and outer retinal layer thickness of perifoveal macular, optic nerve head parameters, and peripapillay retinal nerve fiber layer thickness (pRNFLT) for all included cases were measured using spectral-domain optical coherence tomography. A paired t test was used to compare the differences in the studied parameters between the two groups. The correlations between macular retinal thickness, pRNFLT, disease duration, and age of onset were also analyzed. Results: Among the macular parameters, retinal thickness of macular central fovea (t=—2.135, P < 0.05) and outer retinal layer thickness (t =—1.994, P < 0.05) of patients in the CPEO group were statistically significant lower than those of patients in the normal control group. For the optic nerve head parameters, the patients in the CPEO group showed a larger rim volume (t =—2.499, P < 0.05) and nerve head volume (t =—2.103, P < 0.05). The overall pRNFLT of patients in the CPEO group was statistically significant lower than that of patients in the control group (t =—4.125, P < 0.05). The comparison of pRNFLT in eight sectors showed that the pRNFLT of patients in the CPEO group was statistically significant lower than that of the control group mainly in the inferior and temporal sectors. The degree of pRNFL defect negatively correlated with the disease duration (r =—0.583, P < 0.05). Conclusions: The re

关键词： Optical coherence tomography Chronic progressive external ophthalmoplegia Retina Nerve fiber layer

coherence of Superposition States

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Communications in Theoretical Physics 2019年第9期71卷 1084-1088页

作者：宇文珊珊邵连合席政军 College of Computer Science Shaanxi Normal UniversityXi'an710062China School of Computer Science Xi'an Polytechnic UniversityXi'an710048China

We find tight upper bound on the coherence of a superposition of two states in terms of the coherence of the two states constituting the superposition with l1-norm of coherence. Our upper bound is tighter than the one presented by Liu, et al. [Quantum Inf. Process. 15(2016) 4209.] We also generalize the results to the case that the superposition is constituted with more than two states in high dimension, and we give the corresponding upper bounds.

关键词： quantum coherence superposition states l1-norm of coherence