Crew members of the Starship Enterprise use the transporter to teleport off the ship in the 1965 pilot episode of Star Trek
Like a pair of male turkeys puffing up their chests at each other, the U.S. and Chinese militaries are back at it again, engaging in tit-for-tat military exercises in the Yellow Sea. On Sept. 4, the Chinese navy finished live artillery maneuvers, using some of its newest planes, ships and battlefield weaponry in a publicly announced show of military strength. Though Chinese state media called the war games "routine," the timing of the event — just days before a scheduled U.S.-South Korea anti-submarine exercise in the same waters — suggests it's more likely an attempt to send the U.S. a simple message: This is our backyard.
After watching U.S.-led forces obliterate a Soviet-style Iraqi military in the first Gulf War, China realized it needed to improve its own outdated army. It has increased military expenditures every year for the past two decades. While Chinese officials called the relationship with the U.S. "stable" during talks in Beijing this week, given China's ambitions in the region, tensions between the two are sure to continue. Denny Roy, a senior fellow at the East-West Center in Honolulu, says China is "working towards a sphere of influence," and with their stronger military, they can now "send signals they couldn't before." (See pictures of the making of modern China.)
Thanks to a recent technological breakthrough, that's true literally, too. While China has been showing off its new hardware, a potentially more important military advancement has gone largely unnoticed: In May, Chinese scientists announced a demonstration of "quantum teleportation" over 16 kilometers (10 miles), creating what Matthew Luce, a researcher at the Defense Group Inc.'s Center for Intelligence Research and Analysis, calls "secure communications guaranteed by the laws of physics." China is now at the cutting-edge of military communications, transforming the field of cryptography and spotlighting a growing communications arms race.
While the People's Liberation Army won't be beaming up objects Star Trek-style anytime soon, the new technology could greatly enhance its command and control capabilities. Scientists use machines to manipulate units of light called photons. By changing the photons' quantum states and creating a new, readable pattern not unlike Morse code, they can pass on simple messages or encryption codes. A group of researchers from Tsinghua University and the Hefei National Laboratory for Physical Sciences entangled pairs of photons — linking them so changes to one photon will be instantaneously transferred to the other. Using a high-powered blue laser (the type China appears to be investing in for its submarine fleet), they then transported the quantum information farther than anyone had done before, their paper in Nature Photonics claims.(Read "Is the Future of Electric Cars in China?)
The process is called teleportation, but the information in the message is not actually moved. Instead, changes to one photon's quantum state will be adopted instantly by the other — something Einstein famously called "spooky action at a distance." The result is akin to having two pieces of paper 10 miles apart, and as a person writes on one paper the message simultaneously appears on the other.
Why is this superior to e-mail or radio? Because, theoretically, this method "cannot be cracked or intercepted," says Luce. If the photons in the laser beam are observed by a third party, the particles themselves will be altered due to a law of physics called the Heisenberg Uncertainty Principle, which states that measuring a particle alters it. As such, the sender and receiver would be immediately informed that someone was snooping.
At the 16km distance tested, China would be able to send these secure messages from its network of satellites to units on the ground. Luce also says the choice of a blue laser — instead of an infrared one like the U.S. has been testing — was chosen with its growing submarine fleet in mind since blue lasers penetrate farther underwater. Soon, Chinese satellites could be able to communicate with submarines without them needing to surface or give away their location by breaking radio silence. This may sound like science-fiction, but quantum encryption is already used by a few banks and governments for highly sensitive information on a smaller scale. The Chinese scientists write in Nature Photonics that a quantum communication network could be "within reach of current technology on a global scale."
The advance in secure communications comes none too soon. With ever-increasing computing power, the expiration date on today's cryptography techniques could be looming, Luce says. Right now, breaking modern encryption techniques require such computing power that one can change the code long before a computer has time to crack it. But "it's become very difficult to 'future proof' the encryption of data," Luce writes for the Jamestown Foundation. Tomorrow's computers will improve and data could suddenly become unprotected, while quantum teleportation, he says, "has a seemingly infinite time horizon." (Comment on this story.)
Though the Chinese scientists claim in their peer-reviewed paper that this experiment communicated quantum information more than 20 times farther than previous tests over open space, this may not be entirely true. According to Luce in 2005, a group of universities along with defense corporations with a grant from the Defense Advanced Research Projects Agency (DARPA) transferred quantum information over 23 km (14 miles) in Cambridge, Massachusetts. Though Luce writes that a few differences in the DARPA project "may not technically disqualify the Chinese" from their claims, it's clear the U.S. military is also investing in this technology. Luce says it's difficult to know how far the U.S. is in developing quantum teleportation, "because a lot of the U.S. work is classified."
Of course, what's possible in theory — perfectly secure communication — is different from what will happen in practice. Luce suspects China's pioneering research in this technology is as much an attempt to find weaknesses in a possible U.S. quantum security network as it is to develop its own. Roy of the East-West Center says one of China's "pockets of excellence" is its cyber-warfare capability. If developed by the U.S., however, this technology could help neutralize China's ability to break into sensitive computer systems. Less than two weeks ago, researchers from Germany and Norway claim to have hacked a commercial quantum cryptography system by exploiting flaws in its detection equipment. It doesn't undermine the fundamental principle of secure quantum messaging, but it is a reminder that there is almost always a loophole. "The security of quantum cryptography relies on quantum physics but not only," Gerd Leuchs, a professor at the University of Erlangen-Nürnberg, says in a press release announcing the vulnerabilities. "It must also be properly implemented."
No one claims that the Chinese military will surpass the U.S.' anytime soon, but it isn't just dueling naval exercises that will determine pecking order. It's also how fast China can integrate the newest technologies into its military, maintaining its strengths like cyber-warfare while improving the PLA's precision, coordination and secrecy. In these ways, China has made a quantum leap forward.
翻译：
from :http://item.feedsky.com/~feedsky/dongxinet/~8172838/413166871/6276617/1/item.html
After watching U.S.-led forces obliterate a Soviet-style Iraqi military in the first Gulf War, China realized it needed to improve its own outdated army. It has increased military expenditures every year for the past two decades. While Chinese officials called the relationship with the U.S. "stable" during talks in Beijing this week, given China's ambitions in the region, tensions between the two are sure to continue. Denny Roy, a senior fellow at the East-West Center in Honolulu, says China is "working towards a sphere of influence," and with their stronger military, they can now "send signals they couldn't before." (See pictures of the making of modern China.)
Thanks to a recent technological breakthrough, that's true literally, too. While China has been showing off its new hardware, a potentially more important military advancement has gone largely unnoticed: In May, Chinese scientists announced a demonstration of "quantum teleportation" over 16 kilometers (10 miles), creating what Matthew Luce, a researcher at the Defense Group Inc.'s Center for Intelligence Research and Analysis, calls "secure communications guaranteed by the laws of physics." China is now at the cutting-edge of military communications, transforming the field of cryptography and spotlighting a growing communications arms race.
While the People's Liberation Army won't be beaming up objects Star Trek-style anytime soon, the new technology could greatly enhance its command and control capabilities. Scientists use machines to manipulate units of light called photons. By changing the photons' quantum states and creating a new, readable pattern not unlike Morse code, they can pass on simple messages or encryption codes. A group of researchers from Tsinghua University and the Hefei National Laboratory for Physical Sciences entangled pairs of photons — linking them so changes to one photon will be instantaneously transferred to the other. Using a high-powered blue laser (the type China appears to be investing in for its submarine fleet), they then transported the quantum information farther than anyone had done before, their paper in Nature Photonics claims.(Read "Is the Future of Electric Cars in China?)
The process is called teleportation, but the information in the message is not actually moved. Instead, changes to one photon's quantum state will be adopted instantly by the other — something Einstein famously called "spooky action at a distance." The result is akin to having two pieces of paper 10 miles apart, and as a person writes on one paper the message simultaneously appears on the other.
Why is this superior to e-mail or radio? Because, theoretically, this method "cannot be cracked or intercepted," says Luce. If the photons in the laser beam are observed by a third party, the particles themselves will be altered due to a law of physics called the Heisenberg Uncertainty Principle, which states that measuring a particle alters it. As such, the sender and receiver would be immediately informed that someone was snooping.
At the 16km distance tested, China would be able to send these secure messages from its network of satellites to units on the ground. Luce also says the choice of a blue laser — instead of an infrared one like the U.S. has been testing — was chosen with its growing submarine fleet in mind since blue lasers penetrate farther underwater. Soon, Chinese satellites could be able to communicate with submarines without them needing to surface or give away their location by breaking radio silence. This may sound like science-fiction, but quantum encryption is already used by a few banks and governments for highly sensitive information on a smaller scale. The Chinese scientists write in Nature Photonics that a quantum communication network could be "within reach of current technology on a global scale."
The advance in secure communications comes none too soon. With ever-increasing computing power, the expiration date on today's cryptography techniques could be looming, Luce says. Right now, breaking modern encryption techniques require such computing power that one can change the code long before a computer has time to crack it. But "it's become very difficult to 'future proof' the encryption of data," Luce writes for the Jamestown Foundation. Tomorrow's computers will improve and data could suddenly become unprotected, while quantum teleportation, he says, "has a seemingly infinite time horizon." (Comment on this story.)
Though the Chinese scientists claim in their peer-reviewed paper that this experiment communicated quantum information more than 20 times farther than previous tests over open space, this may not be entirely true. According to Luce in 2005, a group of universities along with defense corporations with a grant from the Defense Advanced Research Projects Agency (DARPA) transferred quantum information over 23 km (14 miles) in Cambridge, Massachusetts. Though Luce writes that a few differences in the DARPA project "may not technically disqualify the Chinese" from their claims, it's clear the U.S. military is also investing in this technology. Luce says it's difficult to know how far the U.S. is in developing quantum teleportation, "because a lot of the U.S. work is classified."
Of course, what's possible in theory — perfectly secure communication — is different from what will happen in practice. Luce suspects China's pioneering research in this technology is as much an attempt to find weaknesses in a possible U.S. quantum security network as it is to develop its own. Roy of the East-West Center says one of China's "pockets of excellence" is its cyber-warfare capability. If developed by the U.S., however, this technology could help neutralize China's ability to break into sensitive computer systems. Less than two weeks ago, researchers from Germany and Norway claim to have hacked a commercial quantum cryptography system by exploiting flaws in its detection equipment. It doesn't undermine the fundamental principle of secure quantum messaging, but it is a reminder that there is almost always a loophole. "The security of quantum cryptography relies on quantum physics but not only," Gerd Leuchs, a professor at the University of Erlangen-Nürnberg, says in a press release announcing the vulnerabilities. "It must also be properly implemented."
No one claims that the Chinese military will surpass the U.S.' anytime soon, but it isn't just dueling naval exercises that will determine pecking order. It's also how fast China can integrate the newest technologies into its military, maintaining its strengths like cyber-warfare while improving the PLA's precision, coordination and secrecy. In these ways, China has made a quantum leap forward.
翻译：
from :http://item.feedsky.com/~feedsky/dongxinet/~8172838/413166871/6276617/1/item.html
近期，美国和中国军方在黄海开展了一系列针锋相对的军事演习。 9月4号，中国海军进行了炮兵部队的实战演戏，动用了最新式的飞机，战舰，武器来炫耀自己的武力。尽管该演习被中国政府称为例行演习，但由于不久前在同样的水域美韩反潜演习刚刚结束，所以在人们看来，中国的军事演习仿佛是在对美国宣告：这是我家的后院。
在看到第一次海湾战争中美国摧毁了清一色苏式装备的伊拉克军队后，中国政府开始意识到升级自己武器装备的必要性，在过去的20年间不断增加军事开支。在本周北京的会谈中，中国官员宣称：中美关系稳固。然而，考虑到中国在该地区的野心，中美关系的紧张不可避免。来自于夏威夷东西文化中心的资深专家丹尼.罗伊说到，“随着日益强大的军事力量，中国正在影响全球的格局。和以往不同的是，他们现在有能力向世界发出信号。
考虑到最近的技术突破，这些消息应该是真实的。当人们的目光都聚集在中国炫耀自己军事设施的时候，另外一项更具潜在的重要性的技术进步却被忽视了：早在今年5月份，中国的科学家宣布，他们实现了超过16公里（10英里）的量子隐态传输，成功建立了量子通信。美国防务集团公司情报研究分析中心研究人员马修.鲁斯称之为“物理学定律保证的绝对安全的通信”。得益于中国顶尖的量子通信技术，中国军方的通信网络正在向量子通信转型，这也让中国处在军事通信的前沿。
虽 然中国人民解放军还不具有星际旅行的能力，但这项新的科技无疑将增强中国军方的执行力和控制力。科学家们利用一种可操作的光单元（光子）作为载体，对光子 的量子态进行操作，转化成一种和莫斯码类似的信息形式，用来传递简单的信息和编码。来自于中国科学技术大学合肥国家实验室和清华大学的研究小组成功地将一 对（远距离，译者补充）的光子纠缠起来（纠缠是指一对光子相互关联，如果对其中一个光子进行操作，相距遥远的另外一个光子将会同时感受到这个操作）。利用 大功率的蓝光激光器（中国似乎正在研发这种激光器运用到潜艇舰队上），他们将量子信息传送的比以往任何人能达到的距离更远（文章发表于《自然.光子》）。
这 种通信过程虽然被我们称之为量子隐态传态，但是信息实际上没有被移动。（不是信息没有被移动，而是光子本身没有被移动。译者注）事实是，对一个光子的量子 态作用瞬间被遥远的另外一个光子感知到了，这种作用被爱因斯坦称之为“远距离的幽灵作用”。这些研究者的实验类似于下面一个形象的比喻：两张分开10英里的白纸，一个人在其中一张白纸上写信息，而信息会同时出现在另一张白纸上。
为什么这种通信方式优于E-Mail或者是无线电通信？ “这是由于这种方法理论上是不能被破译或拦截的”，鲁斯给出了明确的答案。如果激光器中发出的光子被第三方获取，光子的状态就会因为海森堡不确定性关系而改变，这就意味着，光子会因为被测量而改变。这样一来，发送者和接受者就会立刻得知有人在窃听。
在实现16公 里量子通讯测试后，中国将有能力利用他们的卫星系统传输安全信息到地面接收站。鲁斯说不同于美国进行的红外光实验，蓝光可以在水中传输更远距离。考虑到中 国日益壮大的潜艇编队，或许不久将来，中国就能够实现卫星与潜艇的直接通讯，而不再需要潜艇浮出水面或打破无线电静默暴露它们的行踪。这看起来像科幻小 说。但是，量子加密术已经被部分银行和政府用来在小范围里进行绝密信息传输。中国的科学家在自然.光子杂志上写道，“全球量子通讯网络在现有技术上是可以实现的”。
保 密通讯的进步正是恰逢其时。鲁斯认为随着计算能力的不断提高，现今的密钥技术终结的日子已经不远了。破译现代密码术要求计算机计算能力能够实现在通讯方改 变所用密钥之前成功破译。但是在鲁斯写给詹姆斯通基金会的报告中指出“进一步证明数据加密安全性变得非常困难”。未来的计算机会不断进步，数据终有一天会 突然不再安全了。但是对于量子隐形传态，“看起来需要无限长的时间来破译”。
尽管中国科学家在他们的文章里宣称他们的量子信息通讯距离比之前在自由空间所做的实验提高了20倍。这并不完全准确。2005年，在美国国防部高级研究计划局（DARPA）的资助下，马萨诸塞州剑桥的鲁斯的研究小组与军工部门合作成功地将量子信息传送了23公里（14英里）。尽管鲁斯认为他们的DARPA项目与中国科学家的实验有所不同，技术上并不能说中国科学家的宣称有什么不合适的，但很明显美国军方也在研发这项技术。鲁斯指出很难说美国在研发量子隐形传态上究竟做到了什么样的程度，“因为美国许多任务是机密的。
当 然，理论上通讯的绝对安全不等同于实际情况。鲁斯怀疑中国这项前沿技术研究在发展他们自己的量子安全网络的同时，也在试图寻找美国量子网络可能存在的弱 点。夏威夷东西文化中心的罗伊说中国的一个局部优势是他们网络战的能力。倘若量子网络被美国研发出来，这项技术就可以帮助克制中国入侵机密的电脑系统。不 到两周前，来自德国和挪威的研究者宣布他们利用量子网络的探测装置缺陷成功窃听了商用量子密钥系统。它并没有推翻量子信息安全的基本原理，但它告诉我们这 里几乎总是存在漏洞的。“量子密钥的安全性依赖于量子物理，但不止于此，”纽伦堡大学教授盖德.雷彻斯在一篇文章里讨论这些漏洞时认为，“它还必须被恰当地实现。”
没人会认为中国军事力量会在短时间内超越美国，但在最终力量对决中起决定作用的不会仅仅是军事演习比拼。这要看中国能如何快速地将最新技术整合到军队当中，保持网络战强度的同时，提高其精准度，协同性，和保密性。在这些方面，中国已经实现了一次量子大跃进。
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