上次我说最近没有什么物理新闻，我错了。《自然·光子学》8月29号发表了文章

Hacking commercial quantum cryptography systems by tailored bright illumination

（可能打不开，至少我这里需要代理）

文章说他们用实验证明量子加密是有缺陷的，是可以被破解的。如果这是真的，过去数年不断出现的量子通讯新闻恐怕要被这个发现冲淡。

该文也可以在arXiv找到：

arXiv:1008.4593

文章摘要说

The peculiar properties of quantum mechanics allow two remote parties to communicate a private, secret key, which is protected from eavesdropping by the laws of physics. So-called quantum key distribution (QKD) implementations always rely on detectors to measure the relevant quantum property of single photons5. Here we demonstrate experimentally that the detectors in two commercially available QKD systems can be fully remote-controlled using specially tailored bright illumination. This makes it possible to tracelessly acquire the full secret key; we propose an eavesdropping apparatus built from off-the-shelf components. The loophole is likely to be present in most QKD systems using avalanche photodiodes to detect single photons. We believe that our findings are crucial for strengthening the security of practical QKD, by identifying and patching technological deficiencies.

从这个摘要看，还不能肯定这是致命的，也许存在的漏洞将来能够补上：We believe that our findings are crucial for strengthening the security of practical QKD, by identifying and patching technological deficiencies.

Sciencedaily关于此事的报道在这里：Vulnerability in Commercial Quantum Cryptography

另外，朱棣文领导的小组也有一些新的研究进展。在7月份的《自然》上，他们发表了《次纳米单一分子定位和距离测量》，号称将光学显微镜看到的最小物体尺寸从10纳米（百万分之一厘米）降到半纳米左右。

朱棣文在2月份的《自然》上还发表了关于引力的研究，他们过去也在PRL上发表过这类文章，而我和庞毅以及王一还做过相关的理论。其实，用原子干涉研究引力是朱棣文做了很多年的工作。关于引力的文章：

A precision measurement of the gravitational redshift by the interference of matter waves

我这里同样打不开。

他们同原子干涉测量地球引力场中的引力红移，精度达到，而过去最好的精度是，他们整整将这个精度提高了四个量级。这个实验证明了引力是度规理论。

摘要：

One of the central predictions of metric theories of gravity, such as general relativity, is that a clock in a gravitational potential U will run more slowly by a factor of 1 + U/c2, where c is the velocity of light, as compared to a similar clock outside the potential1. This effect, known as gravitational redshift, is important to the operation of the global positioning system, timekeeping and future experiments with ultra-precise, space-based clocks (such as searches for variations in fundamental constants). The gravitational redshift has been measured using clocks on a tower, an aircraft and a rocket, currently reaching an accuracy of 7 × 10-5. Here we show that laboratory experiments based on quantum interference of atoms9, 10 enable a much more precise measurement, yielding an accuracy of 7 × 10-9. Our result supports the view that gravity is a manifestation of space-time curvature, an underlying principle of general relativity that has come under scrutiny in connection with the search for a theory of quantum gravity11. Improving the redshift measurement is particularly important because this test has been the least accurate among the experiments that are required to support curved space-time theories.