We experimentally demonstrate observation of highly pure four-photon GHZ entanglement producedby parametric down-conversion and a projective measurement. At the same time this also demonstrates
teleportation of entanglement with very high purity. Not only does the achieved high visibility enablevarious novel tests of quantum nonlocality, it also opens the possibility to experimentally investigatevarious quantum computation and communication schemes with linear optics. Our technique can, inprinciple, be used to produce entanglement of arbitrarily high order or, equivalently, teleportation and entanglement swapping over multiple stages.

从 Ma Yue 的英文 blog 了解到，AIP 的 Scitation 的文献搜索结果可以通过 rss 订阅了。它的数据库除 Scitation 外，还包含有 SPIN。不过后者需要订阅，rss feed 就等于没用了。但是，Scitation 包含的杂志数量已经非常巨大了，主要的物理类杂志基本都有了。

格志上有过免费科学计算软件的讨论，今天在煎蛋看到两个以前没注意到过的：Maxima 和 R。前者与 Maple 类似，代数运算强；后者是个统计运算软件。

VideoLectures.net 这个网站有不少学科的演讲、授课、辅导、和采访视频。说不定能找到你感兴趣的。

Michael Nielsen 新推出一个网站：The Academic Reader，值得期待。

The Academic Reader is a new web site that makes it easier to keep track of your scientific reading. Rather than going to multiple websites every day to keep up, we pull all the sources together in a single location, so you can keep track easily. Sources include the preprint arXiv, the Physical Review, and Nature, and many new sources will be added in the months to come, including sources outside physics.

Michael Nielsen 是量子信息与计算领域一年轻大牛，也是很有影响力的科学 blogger，虽然现在不大写了。他推出这个 Academic Reader 让我想起格志之前介绍过的，Dave Bacon 推出 SciRate.com。他们都属于 web savvy 的科学家。

激发人创建科学研究相关 web 应用，也是格志一个梦想。