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multipartite entanglement of a Tetrahedron Lattice

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Communications in Theoretical Physics 2006年第5X期46卷 863-872页

作者： ZHANG Rong ZHU Shi-Qun HAO Xiang School of Physical Science and Technology Suzhou University Suzhou 215006 China

Three-dimensional Heisenberg model in the form of a tetrahedron lattice is investigated. The concurrence and multipartite entanglement are calculated through 2-concurrence C and 4-concurrence C4. The concurrence C and multipartite entanglement G4 depend on different coupling strengths Ji and are decreased when the temperature T is increased. For a symmetric tetrahedron lattice, the concurrence C is symmetric about J1 when J~ is negative while the multipartite entanglement G4 is symmetric about J1 when J2 〈 2. For a regular tetrahedron lattice, the concurrence G of ground state is 1/3 for ferromagnetic case while G = 0 for antiferromagnetic ***. However, there is no multipartitc entanglement since C4=0 in a regular tetrahedron lattice. The external magnetic field 13 can increase the maximum value of the concurrence GB and induce two or three peaks in Cn. There is a peak in the multipartite entanglement G4 B when G4B is varied as a function of the temperature T. This peak is mainly induced by the magnetic field B.

关键词： multipartite entanglement concurrence three dimensions tetrahedron lattice

Precise detection of multipartite entanglement in four- qubit Greenberger-Horne-Zeilinger diagonal states

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Frontiers of physics 2018年第5期13卷 281-293页

作者： Xiao-Yu Chen Li-Zhen Jiang Zhu-An Xu College of Information and Electronic Engineering Zhejiang Gongshang University Hangzhou 310018 China Department of Physics Zhejiang University Hangzhou 310027 China

We propose a method of constructing the separability criteria for multipartite quantum states on the basis of entanglement witnesses. The entanglement witnesses are obtained by finding the maximal expectation values of Hermitian operators and then optimizing over all possible Hermitian operators. We derive a set of tripartite separability criteria for the four-qubit Greenberger-Horne-Zeilinger （GHZ） diagonal states. The derived criterion set contains four criteria that are necessary and sufficient for the tripartite separability of the highly symmetric four-qubit GHZ diagonal states; the criteria completely account for the numerically obtained boundaries of the tripartite separable state set. One of the criteria is just the tripartite separability criterion of the four-qubit generalized Werner states.

关键词： multipartite entanglement matched entanglement witness GHZ diagonal state

Genuine (k,m)-Threshold Controlled Teleportation and multipartite entanglement

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Communications in Theoretical Physics 2011年第6期55卷 977-983页

作者：汪新文李大创杨国健张登玉 Department of Physics and Electronic Information Science Hengyang Normal University Department of Physics Beijing Normal University Department of Physics and Electronic Engineering Hefei Normal University

We propose genuine （k, m）-threshold controlling schemes for controlled teleportation via multi-particle entangled states, where the teleportation of a quantum state from a sender （Alice） to a receiver （Bob） is under the control of m supervisors such that k （k≤ m） or more of these supervisors can help Bob recover the transferred state. By construction, anyone of our quantum channels is a genuine multipartite entangled state of which any two parts are inseparable. Their properties are compared and contrasted with those of the well-known GHZ, W, and linear cluster states, and also several other genuine multipartite entangled states recently introduced in the literature.

关键词： threshold controlled teleportation multipartite entanglement

Effect of the dispersion on multipartite continuous-variable entanglement in optical parametric amplifier

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Chinese Physics B 2015年第4期24卷 42-45页

作者：赵超樱 College of Science Hangzhou Dianzi University State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-ElectronicsShanxi University

Based on the quantum fluctuations, we adopt the method of generalized V1 criterion to investigate multipartite entan- glement characteristics in an optical parametric amplification system with the consideration of dispersion. The nonlinear interaction becomes strong because of the existence of dispersion coefficient σ. Considering the influence of dispersion factor σ, with increasing the pump parameter μ, the value of minimum variance V1 decreases and the squeezing curve nearly equals 1/（1 ＋ μ）. The larger particle number N results in a smaller variance and higher entanglement.

关键词： dispersion multipartite entanglement optical parametric amplifier

Dissipative preparation of multipartite Greenberger-Horne-Zeilinger states of Rydberg atoms

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Chinese Physics B 2021年第2期30卷 71-78页

作者： Chong Yang Dong-Xiao Li Xiao-Qiang Shao Center for Quantum Sciences and School of Physics Northeast Normal UniversityChangchun 130024China Center for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of EducationNortheast Normal UniversityChangchun 130024China School of Physics International Joint Laboratory on Quantum Sensing and Quantum MetrologyHuazhong University of Science and TechnologyWuhan 430074China

The multipartite Greenberger-Horne-Zeilinger(GHZ)states play an important role in large-scale quantum information *** utilize the polychromatic driving fields and the engineered spontaneous emissions of Rydberg states to dissipatively drive three-and four-partite neutral atom systems into the steady GHZ states,at the presence of the nextnearest neighbor interaction of excited Rydberg ***,the introduction of quantum Lyapunov control can help us optimize the dissipative dynamics of the system so as to shorten the convergence time of the target state,improve the robustness against the spontaneous radiations of the excited Rydberg states,and release the limiting condition for the strengths of the polychromatic driving *** the feasible experimental conditions,the fidelities of three-and four-partite GHZ states can be stabilized at 99.24%and 98.76%,respectively.

关键词： multipartite entanglement Lyapunov control Rydberg antiblockade quantum dissipation

Quantum Information Processing in An Array of Fiber Coupled Cavities

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Communications in Theoretical Physics 2010年第4期53卷 764-770页

作者：李建邹健邵彬 Department of Physics Beijing Institute of Technology

We consider a fiber coupled cavity array. Each cavity is doped with a single two-level atom. By treating the atom-cavity systems as combined polaritonie qubits, we can transform it into a polaritonic qubit-qubit array in the dispersive regime. We show that the four fiber coupled cavity open chain and ring can both generate the four qubit W state and cluster state, and can both transfer one and two qubit arbitrary states. We also discuss the dynamical behaviors of the four fiber coupled cavity array with unequal couplings.

关键词： fiber coupled cavity array state transfer multipartite entanglement

Two Schemes for Generation of entanglement for Vibronic Collective States of Multiple Trapped Ions

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Communications in Theoretical Physics 2007年第3期47卷 421-426页

作者： YANG Wen-Xing LI Jia-Hua ZHNG An-Shou Department of Physics Southeast University NanJing 210096 China Molecular Physics Center for Cold Atom Physics Wuhan Institute of Physics and Mathematics the Chinese Academy of Sciences Wuhan 430071 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

We propose two schemes to prepare entanglement for the vibronic collective states of multiple trapped ions. The first scheme aims to generating multipartite entanglement for vibrational modes of trapped ions, which only requires a single laser beam tuned to the ionic carrier frequency. Our scheme works in the mediated excitation regime, in which the corresponding Rabi frequency is equal to the trap frequency. Beyond their fundamental importance, these states may be of interest for experimental studies on decoherence since the present scheme operates in a fast way. The second scheme aims to preparing the continuous variable multimode maximal1y Greenberger-Horne-Zeilinger state. The distinct advantage is that the operation time is only limited by the available laser intensity, not by the inherent mechanisms such as off-resonant excitations. This makes it promising to obtain entanglernent of multiple coherent and squeezing states with desired amplitudes in a reasonable time.

关键词： multipartite entanglement GHZ state trapped ions

Detection of the quantum states containing at most k−1 unentangled particles

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Chinese Physics B 2021年第10期30卷 149-153页

作者： Yan Hong Xianfei Qi Ting Gao Fengli Yan School of Mathematics and Science Hebei GEO UniversityShijiazhuang 050031China School of Mathematics and Statistics Shangqiu Normal UniversityShangqiu 476000China School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024China College of Physics Hebei Normal UniversityShijiazhuang 050024China

There are many different classifications of entanglement for multipartite quantum systems,one of which is based on the number of the unentangled *** this paper,we mainly study the quantum states containing at most k−1 unentangled particles and provide several entanglement criteria based on the different forms of inequalities,which can both identify quantum states containing at most k−1 unentangled *** show that these criteria are more effective for some states by concrete examples.

关键词： multipartite entanglement k−1 unentangled particles Cauchy-Schwarz inequality

Effect of Different Environments on multipartite Global Discord

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Communications in Theoretical Physics 2015年第3期63卷 291-295页

作者：徐宝明邹健李军刚邵彬 School of Physics Beijing Institute of Technology

We investigate the influences of non-Markovian dissipation and global dephasing process on the dynamical behaviors of global discord among four *** find that for the non-Markovian dissipation model W state is the most robust to decoherence compared to Dicke and GHZ states;however,for the global dephasing model Dicke state is the most robust to decoherence among *** the dynamical behaviors of global quantum discord are quite different from that of the multipartite entanglement for the non-Markovian dissipation model,while they are very similar to each other for the global dephasing model.

关键词： global discord non-markovian multipartite entanglement decoherence