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Fidelity of states in infinite-dimensional quantum systems

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Science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1820-1827页

作者： HOU JinChuan qi xiaofei Department of Mathematics Taiyuan University of TechnologyTaiyuan 030024China Department of Mathematics Shanxi UniversityTaiyuan 030006China

We discuss the fidelity of states in the infinite-dimensional systems and give an elementary proof of the infinite-dimensional version of Uhlmann's *** theorem is used to generalize several properties of the fidelity of the finite-dimensional case to the infinite-dimensional *** are somewhat different from those for the finite-dimensional case.

关键词： Hilbert space trace quantum states fidelity entanglement fidelity

Quantum correlations in a chain-type quantum network

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Communications in Theoretical Physics 2024年第6期76卷 77-91页

作者： xiaofei qi Aihong Zhai Lihua Yang School of Mathematical Science Shanxi UniversityTaiyuan 030006China Key Laboratory of Complex Systems and Data Science of Ministry of Education Shanxi UniversityTaiyuan 030006China School of Mathematics and Information Technology Yuncheng UniversityYuncheng 044000China

A quantum network concerns several independent entangled resources and can create strong quantum correlations by performing joint measurements on some *** this paper,we discuss an n-partite chain network with each of two neighboring observers sharing an arbitrary Bell state and all intermediate observers performing some positive-operator-valued measurements with parameterλ.The expressions of all post-measurement states between any two observers are obtained,and their quantifications of Bell nonlocality,Einstein-Podolsky-Rosen steering and entanglement with different ranges ofλare respectively detected and analyzed.

关键词： quantum correlation nonlocality entanglement chain-type quantum network

Characterization of Lie multiplicative isomorphisms between nest algebras

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Science China Mathematics 2011年第11期54卷 2453-2462页

作者： qi xiaofei HOU JinChuan Department of Mathematics Shanxi University Taiyuan 030006 China Department of Mathematics Taiyuan University of Technology Taiyuan 030024 China

Let N and M be nests on Banach spaces X and Y over the real or complex field F, respectively, with the property that if M ∈ M such that M_ =M, then M is complemented in Y. Let AlgN and AlgM be the associated nest algebras. Assume that Ф ： AlgN → AlgM is a bijective map. It is proved that, if dim X = ∞ and if there is a nontrivial element in N which is complemented in X, then Ф is Lie multiplicative （i.e. Ф（[A, B]） = [Ф（A）, Ф（B）] for all A, B ∈ AlgN） if and only if Ф has the form Ф（A） = TAT^-1 ＋ τ（A） for all A ∈ AlgAN or Ф（A） = -TA^＊T^-1 ＋ τ（A） for all A ∈ AlgN, where T is an invertible linear or conjugate linear operator and τ ： AlgN →FI is a map with τ（[A, B]） = 0 for all A, B ∈ AlgN. The Lie multiplicative maps are also characterized for the case dim X 〈 ∞.

关键词： Banach spaces nest algebras Lie ring isomorphisms Lie multiplicative maps

Sufficient and necessary conditions of separability for bipartite pure states in infinite-dimensional systems

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Chinese Science Bulletin 2011年第9期56卷 840-846页

作者： GUO Yu qi xiaofei HOU JinChuan Department of Mathematics Shanxi University Taiyuan 030006 China Department of Mathematics Shanxi Datong University Datong 037009 China Department of Mathematics Taiyuan University of Technology Taiyuan 030024 China

The PHC criterion and the realignment criterion for pure states in infinite-dimensional bipartite quantum systems are given. Furthermore, several equivalent conditions for pure states to be separable are generalized t... 详细信息

关键词：无限维系统充分必要条件分离纯态状态描述正线性算子量子力学希尔伯特

Additive Biderivations and Centralizing Maps on Nest Algebras

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Journal of Mathematical Research with Applications 2013年第2期33卷 246-252页

作者： xiaofei qi Department of Mathematics Shanxi University

Let N be a nest on a Banach space X,and AlgN be the associated nest *** is shown that,if there exists a non-trivial element N in N which is complemented in X and dim N = 1,then every additive biderivation from AlgN into itself is an inner *** on this result,we give characterizations of centralizing(commuting) maps,cocentralizing derivations,and cocommuting generalized derivations on nest algebras.

关键词： biderivations commuting maps centralizing maps nest algebra.

Facile Fabrication and Optical Properties of Nanostructural PbSe Films

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Chemical Research in Chinese Universities 2014年第6期30卷 987-990页

作者： LIU Meng qi xiaofei WU Xionggang ZHANG Hengning Xi 'an Modern Chemistry Research Institute Xi 'an 710065 P. R. China

PbSe films with different nanostructures, such as nanoparticles, nanohollows and hierarchical structures, can be synthesized by adjusting the current density and the reaction temperature via a convenient and efficient electrochemical route in the absence of hard template and surfactant. The calculated band gaps of the prepared PbSe nanoparticles and nanohollows were about 0.32 and 0.43 eV, respectively. This suggests that quantum size effect in nanohollows greatly influences their band gap. This preparation method possesses remarkable advantages, such as low cost, high efficiency and easy preparation, which are very suitable for preparing nanomaterials.

关键词： Thin film PbSe Electrodeposition Nanostructural material Optical property

Creep damage evolution process of asphalt binder based on viscoelastic characteristics

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 497-506页

作者： xiaofei qi Shuang Tian Liyan Shan Shuang Liu Yajie Wang School of Transportation Science and Engineering Harbin Institute of TechnologyHarbin 150090China College of Water Conservancy&Architectural Engineering Shihezi UniversityShihezi 832003China

The creep damage evolution of asphalt binder plays a significant role in investigating the formation mechanism of *** rutting is the common distress at high temperatures for asphalt ***,the reliability of existing creep damage parameters is under questioned,and these parameters cannot accurately illustrate the change of intrinsic microstructure for asphalt *** this paper,a new test protocol was given access to study the evolution of viscoelastic parameters during creep *** was completed by inserting the frequency sweep during creep *** frequency sweep curve clusters were fitted by the generalized Kelvin-Voigt model for obtaining the change law of model *** on the change law and sensitivity analysis of model parameters,(E_(2)+E_(3))/2 was proposed as the creep damage *** to the curve of(E_(2)+E_(3))/2 versus loading time,two stages during the creep test could be identified:an approximate constant value in phase I and a linear decrease in phase *** differences about creep property of binders could be determined by this new proposed *** results not only ensure better understanding of the creep damage mechanism of binders,but also lay the theoretical foundation on predicting the anti-rutting performance of binders.

关键词： Asphalt binder Multi-stage creep test Damage variable Evolution law

Combustion Properties of Metal Particles as Components of Modified Double-Base Propellants

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Journal of Beijing Institute of Technology 2018年第2期27卷 293-301页

作者： xiaofei qi Hongyan Li Ning Yan Ying Wang Xueli Chen Xi'an Modern Chemistry Research Institute Xi'an 710065China Science and Technology on Combustion and Explosion Laboratory Xi'an 710065China

Metal particles such as aluminum（ Al）,magnesium（ Mg）,boron（ B） and nickel（ Ni）,as well as Mg/Al alloy（ Mg/Al = 3/4） are currently the most widely used ingredients in modified doublebase propellants. In this contribution,the combustion properties of the metal species are studied by means of the high-speed photography technique and the non-contact wavelet-based measurement of flame temperature distribution. The combustion process of the Al,Mg and Mg/Al samples shows both gas phase reaction and surface oxidation,which yield volatile and nonvolatile products,corresponding to the oxide and suboxide respectively. However,the combustion of B and Ni shows only gas phase reaction,due to their high melting point as well as high enthalpy of vaporization. In addition to the experiments,a hypothetical combustion model has been proposed to clarify the combustion characteristics of metal species in modified double-base propellants.

关键词： metal particles modified double-base propellant combustion properties flame structure

Physical origins of ruled surfaces on the reduced density matrices geometry

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Science China(Physics,Mechanics & Astronomy) 2017年第2期60卷 1-8页

作者： Ji-Yao Chen Zhengfeng Ji Zheng-Xin Liu xiaofei qi Nengkun Yu Bei Zeng Duanlu Zhou State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing 100084 China Perimeter Institute for Theoretical Physics Waterloo N2L 2Y5 Canada Centre for Quantum Computation ＆ Intelligent Systems School of Software Faculty of Engineering and Information Technology University of Technology Sydney Sydney 2007 Australia State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China Department of Physics Renmin University of China Beijing 100872 China Department of Mathematics Shanxi University Taiyuan 030000 China Institute for Quantum Computing University of Waterloo Waterloo N2L 3G1 Canada Department of Mathematics ＆ Statistics University of Guelph Guelph N1G 2W1 Canada Institute of Physics Chinese Academy of Sciences Beijing 100190 China

The reduced density matrices （RDMs） of many-body quantum states form a convex set. The boundary of low dimensional projections of this convex set may exhibit nontrivial geometry such as ruled surfaces. In this paper, we study the physical origins of these ruled surfaces for bosonic systems. The emergence of ruled surfaces was recently proposed as signatures of symmetry- breaking phase. We show that, apart from being signatures of symmetry-brealdng, ruled surfaces can also be the consequence of gapless quantum systems by demonstrating an explicit example in terms of a two-mode Ising model. Our analysis was largely simplified by the quantum de Finetti＇s theorem--in the limit of large system size, these RDMs are the convex set of all the symmetric separable states. To distinguish ruled surfaces originated from gapless systems from those caused by symmetry- breaking, we propose to use the finite size scaling method for the corresponding geometry. This method is then applied to the two-mode XY model, successfully identifying a ruled surface as the consequence of gapless systems.

关键词： ruled surfaces reduced density matrices bosonic system geometry