Generation of four-photon entangled states based on interaction between a three-level atom and two bimodal cavities

A simple scheme is presented for generating four-photon entangled states with interaction between a three-level atom and two bimodal cavities.In the proposed protocol,the quantum information is encoded on Fock states of the cavity fields.The detection of the atom can collapse the cavity made/wave function to the desired state.The experimental feasibility of our proposal is also discussed.     

基于纠缠相干性的量子投票方案

提出了一个基于3粒子态纠缠相干性的量子投票方案,利用量子力学的物理特性来实现投票、计票和即时监督.此外,方案还采用了量子密钥分配和一次一密算法,克服了传统电子投票协议中普遍存在的计算安全性的局限,具有无条件安全性.     

Color characterization of roofing slates from the Iberian Peninsula for restoration purposes

Substitution of slate roofing tiles is a conventional operation during building restoration, since tiles are very difficult to restore or clean because of the high degree of alteration they suffer. Criteria for replacement of historical building stones must be based on geological, geotechnical and esthetic parameters, among which color is of great importance. In this sense, this paper constitutes a comprehensive and useful colorimetric study of roofing slates from the Iberian Peninsula, for the purposes of restoration. The color of 50 commercial varieties of roofing slate mined in quarries from the 12 mining districts in the Iberian Peninsula was analyzed with a spectrophotometer device, by considering the CIELAB color space. The results of the study were used to develop a protocol for characterizing the color of roofing slate and to define the color range of roofing slate from the Iberian Peninsula. In addition, the similarities and differences in the color and microstructure of the different commercial varieties of Iberian roofing slate were established and the limit of acceptability of replacement of one type of slate by another was determined. Parameter h_ab was found to be the most important CIELAB color coordinate as regards the formation of homogeneous color groups, and the specular component excluded (SCE) mode was most sensitive as regards detecting color differences between two samples.     

阶梯型三能级原子与双模腔作用制备四光子GHZ态

通过阶梯型三能级原子与双模腔大失谐作用,提出制备四光子Greenberger-Horne-Zeilinger（GHZ）态的方案。光子作为量子信息载体,通过对原子的测量得到所需要的量子态。该方案具有实验可行性。     

多个囚禁离子未知类电子GHZ态的确定量子隐形传送

利用n＋1个两能级离子的纠缠GHZ态作为量子隐形传送的量子通道，提出一个有效的方案隐形传送未知n个离子的类电子纠缠GHZ态．本方案有以下显著特点：对囚禁离子振动模的加热不敏感；不需要对单个离子进行激光操控；操作简单，三步完成，成功传送的几率为1．     

通过对单原子的局域测量实现纠缠纯化

从两对原子的纠缠态出发 ,通过对单原子的局域测量 ,实现了纠缠的纯化 该方案不同于一般的通过联合的Bell基测量而实现纠缠纯化的过程 在此方案里 ,纯化包含两方面的含义 ,即四原子的纠缠态纯化为两原子纠缠态以及部分两原子纠缠态纯化为最大纠缠态     

Airtime for Newcomers

This article explores the British and West German public service radio’s abilities to reflect on and to address the specific needs and expectations of migrant groups in their programmes between the 1960s and 1980s. Mechanisms of social inclusion and exclusion alike can be investigated here. Empirically, it is based on comparisons of radio broadcasts on and for different immigrant communities, produced by BBC Radio Leicester on/for the post-war Asian migrants in England and by West German public service broadcasting on/for ‘Gastarbeiter’ (foreign workers) as well as for ‘Spätaussiedler’ (German repatriates from East Europe). Radio is studied as an agent of identity management and citizenship education. Not only did radio talk about migrants and migration to introduce these topics and the newcomers to the local population. It also offered airtime to selected migrant communities to cater for their needs and interests as well as to facilitate their difficulties of adjusting to an unfamiliar environment.     

两体高维量子系统的Negativity

量子纠缠及其度量在量子通讯中起着至关重要的作用．文章采用一种量子纠缠的计算方法--Negativity，推导得到了二参量两体高维量子系统Negativity的一般解析表达式．此方法的优点是计算方便，物理意义明确．     

多梦时代听书声——解读明代读书石板深浮雕

明代读书石板深浮雕记载了书院授课的情景,反映了这一时期人人乐学上进、尊师重教的社会风貌,启示后人在盛世之年、多梦时代要多读书、勤读书。