Transformation relation between coherence and entanglement for two-qubit states

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 two-qubit 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.     

简论大学组织的文化管理

大学组织的文化管理是在企业文化管理理论的影响下产生和发展起来的,它是借助大学组织文化对大学成员的影响力达成教育管理目标的一种管理模式.大学组织实施文化管理,主要应树立人文化的管理理念,制定人本化的管理目标,营造人情化的管理氛围,设计人性化的管理制度,构建人权化的管理机制.实践中,还要遵循价值引领、公平民主、崇尚尊重、达致和谐等基本原则.     

Economical phase-covariant cloning with multiclones

This paper presents a very simple method to derive the explicit transformations of the optimal economical 1 to M phase-covariant cloning. The fidelity of clones reaches the theoretic bound [D'Ariano G M and Macchiavello C 2003 Phys. Rev. A 67 042306]. The derived transformations cover the previous contributions [Delgado Y, Lamata L et al, 2007 Phys. Rev. Lett.98 150502] in which M must be odd.     

Dynamics of entanglement under decoherence in noninertial frames

In this paper,we investigate the entanglement dynamics of a two-qubit entangled state coupled with its noisy environment,and plan to utilize weak measurement and quantum reversal measurement to study the entanglement dynamics under different decoherence channels in noninertial frames.Through the calculations and analyses,it is shown that the weak measurement can prevent entanglement from coupling to the amplitude damping channel,while the system is under the phase damping and flip channels.This protection protocol cannot prevent entanglement but will accelerate the death of entanglement.In addition,if the system is in the noninertial reference frame,then the effect of weak measurement will be weakened for the amplitude damping channel.Nevertheless,for other decoherence channels,the Unruh effect does not affect the quantum weak measurement,the only exception is that the maximum value of entanglement is reduced to√2/2of the original value in the inertial frames.     

独立同分布随机变量加权和的概率估计

设{ξ_i}_i=1ⁿ为独立同分布的随机变量,且P(ξ_i=1)=P(ξ_i=-1)=1/2.设a=(a₁,…,a_n)为与{ξⁱ}_i=1ⁿ独立的服从超球面S^n-1={(a₁,…,a_n)∈Rⁿ|∑_i-1ⁿ a_i²=1}上均匀分布的随机变量,该文用极坐标变换得到了P(|∑_i=1ⁿ a_iξ_i|≤1)的表达式.当n<7时,该文通过直接计算得到此概率值大于等于1/2;当n≥8时,该文通过R软件也得到了此概率值大于等于1/2.特别地,n=3,4时,借助于贝塔函数,该文直接证明了该概率值大于等于1/2.     

含盐生活污水处理中的硝化菌种群优化

为了实现稳定的短程硝化, 通过使用 NaCl 作为一种选择抑制剂(只抑制亚硝酸氧化菌(NOB)的生长而不会以抑制氨氧化菌(AOB) 的生长) 在序批式反应器处理含盐生活污水过程中实现硝化种群的优化。实验考察了不同盐度对 AOB 和 NOB 的抑制程度以及对系统硝化性能的影响, 选择 7. 6 g/ L的盐度作为种群优化的最佳盐度。长期抑制实验实施 4 个月后, 亚硝酸盐积累稳定在 95% 以上, 短程硝化稳定。利用荧光原位杂交技术(FISH) 检测到AOB (Nitrosospira) 已经成为硝化菌群的主导菌种, NOB(Nitrobacter)基本检测不出, 证明 NOB 已经被淘洗出系统,硝化种群得到优化。同时讨论了盐度对 NOB 的选择抑制机理。     

A nearly deterministic scheme for generation of multiphoton GHZ states with weak cross-Kerr nonlinearity

We propose a scheme to generate polarization-entangled multiphoton Greenberger-Horne-Zeilinger (GHZ) states based on weak cross-Kerr nonlinearity and subsequent homodyne measurement. It can also be generalized to produce maximally N-qubit entangled states. The success probabilities of our schemes are almost equal to 1.     

Scheme to implement optimal asymmetric economical 1→3 phase-covariant telecloning via cavity QED

<正>We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→3 phase-covariant telecloning protocol,which works without ancilla,based on cavity quantum electrodynamics(QED).The scheme is insensitive to the cavity field states and the cavity decay.In the telecloning process,the cavity is only virtually excited,it greatly prolongs the efficient decoherent time.Therefore,the scheme may be experimentally realized in the field of current cavity QED techniques.     

Probabilistic teleportation of an unknown atomic state

We propose two schemes for teleporting an unknown state. In our schemes, a three-particle Greenberger－Horne－Zeilinger state is used as a quantum channel. We show that the probabilistic teleportation of an unknown quantum state can be realized.     

含类Kerr介质的双光子Jaynes-Cummings模型中的反聚束效应

研究了一个两能级原子处于充满了类Ｋｅｒｒ介质的高Ｑ腔里与单模辐射场双光子相互作用的系统中,光场的反聚束效应,着重讨论了原子处于不同初始条件下类Ｋｅｒｒ介质与单模场作用的耦合强度和失谐量对光场反聚束效应的影响。