China will launch the world's first quantum scientific experiment satellite

At the Jiuquan Satellite Launch Center, the star combination cover lifting, docking with the launch vehicle, Xinhua

"Mozi" test in

"Mo" in the dock with the launch vehicle adapter

Quantum is a particularly serious, but it's easy to make no serious advanced topics. Quantum scientific experimental satellite China "Mozi" is about to launch, blanket coverage for many people to think of this as dinner conversation.

However, I'm afraid no one can beat their breasts and well versed in quantum theory, even when the creation and development of quantum theory of physics leaders think this stuff is hard to understand that ordinary people would not have.

Different from classical physics and many other subjects, quantum theory violated common sense and intuition. Some seemingly unrelated phenomena can combine into one, make people laugh or cry, so nonsensical theory to understand?

According to Xinhua News Agency, Beijing, August 15

Quantum entanglement of Einstein's tangle

Quantum is the smallest share of things in the physical world. In mathematics, you can put things into half and half endlessly reduced, but physics can not be smaller than one quantum, might say the whole world is composed of quantum.

Quantum theory has made many predictions have been proved, no quantum theory, can not understand the principles of semiconductor materials, made out of tiny transistors, there will be no integrated circuits, there would be no computers, cell phones and the Internet.

The status of quantum theory has a solid, with a lot of physicists on it, but some of the fundamental problems of the quantum world, is their common problems. One of the most important one, is the Einstein of hanging for years, still wrestling with today's "action at a distance", which is the basis of quantum communication and quantum scientific experiment satellite test questions, its official title is "entangled".

We are on two entangled particles, there is a mysterious relationship with each other, even if the universe apart, as long as the struggle not to be broken, the association exists. Mysterious quantum entanglement that action at a distance, was plagued by many of the best human minds.

Humans seem to be born to believe that the principle of locality is taken for granted, that an object can be directly affected by the surroundings, things far away through the media, effects across space to it. To end up the coffee cup on the table, you have to grab. I shouted to you, sound vibrations to pass through the air.

Quantum entanglement means that quantum theory is flawed or locality principles can be violated. While represented by Einstein some physicists are sceptical about the existence of action at a distance, just think that quantum theory is "incomplete", entangled particles exist between some haven't observed interactions or communications, or "hidden variables".

Physicist John Bell designed principle, battlefield shift from theory of quantum entanglement to the laboratory. In emotional Bell in Einstein's side, but this does not affect the theory--known as the "Bell's inequalities"--objectivity. For decades, scientists using photons, atoms, ions and other things did a lot of experiments, the results are biased quantum theory: no hidden variables exist, quantum entanglement is a locality.

But Bell's design of experiments is a hypothetical experiment, in reality it is difficult to fully meet the requirements of principle experiment, so far no one reliable enough to be conclusive. Experimental distance, is one means of eliminating loopholes, quantum scientific experimental satellite experimental distance can be extended to an unprecedented level, and hope to arrive at more reliable results. Of course, located at the other end of the future if we can experiment on the Moon or even Mars, is even more ideal.

Quantum communication "do not block" key

Quantum scientific experimental satellite is another task for quantum communications experiment, which is closer to the reality in the field of quantum entanglement. The gist of it is particularly safe, traditional wiretapping, in principle, no use to quantum communications. Encrypted information is locked boxes, with a specific key to open it. Current encryption technology, as long as enough effort, key can theoretically be intercepted only high efficiency is not high.

Quantum entanglement and provides "do not block" key. Practice is not calculated to prevent theft of keys, but once it was done, both sides can detect. Quantum satellite plan to create two entangled photons, one each for the communicating parties. Both sides on the respective receiving photons of random testing, using clear-text communication compared test results, look at the two entangled photons are not. If someone intercepted Photon, its observation undermines entangled state, make keys obsolete--you steal, steal is useless, I switched to the new key.

There are many technical difficulties from theory to practice, but on the whole, quantum communications is much more than a traditional communication security, encryption technology will bring revolutionary changes. Quantum communication in recent years there had been small scale, this satellite is to be launched in China to take the lead in a big building worldwide quantum communication networks. Foreign Media commented that it was "leading research into a milestone in China's global strategic asset."

Quantum computing magic by high-speed computing

Quantum entanglement also has a better, but more distant applied fields: quantum computing. Traditional computer not far from its theoretical limit seems to have been, both physical hardware limitations caused, there are limitation software algorithm. For some huge computational problems, traditional computer consumes humans can't afford to wait for a long time, and even the universe can't now quantum computer is the only possible way out, it will be millions of times faster than conventional computers.

Traditional computer algorithms based on 0 or 1 State, and quantum computers can achieve "is both 1 and 0", multiple entangled qubit can simultaneously achieve exponential increasing levels of computing power, easy rolling traditional parallel computing.

Of course, the research is still at a very basic stage, many problems have yet to be answered: what make quantum bits? How to sustain their fragile and short-lived, are particularly vulnerable to disturbance of quantum States? How to program them? Making quantum computers are not needed are different from traditional computer brand new thoughts? In traditional computer history to match words, quantum computing probably is still in the research and development of vacuum tube era, let us wait ... ...

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Why is it called "mo"?

15th reporters learned from the Chinese Academy of Sciences, China is going to launch the world's first quantum scientific experiment satellite was named "mo".

"On the satellite's name we considered for a long time. "Quantum scientific experimental satellite's Chief Scientist, academician Pan Jianwei said, eventually named Mo, originated from the famous educator, Professor of the China University of science and technology and old Qian linzhao.

It is understood that the Qian linzhao as the older generation of optics, history of science and technology studies, early years further study of Mohist classics the book of ink have been found a lot of records linked with modern scientific knowledge, such as Mozi proposed in the Mohist "optical eight."

"Mohist school's logic is one of the three oldest system, which system is the basis of science. "Pan Jianwei said, MO discovered more than 2000 years ago that light travels in straight lines, and designed a pinhole camera experiments laid the Foundation of optical communication, quantum communication.

"Like foreign satellites, Kepler, Galileo, named after great sages of ancient China the world's first quantum satellite, will promote China's cultural self-confidence. "He said.

It is understood that as a strategic pilot project of the Chinese Academy of Sciences, space sciences one of the first scientific satellite, quantum scientific experiment satellite will star at the international first high-speed quantum key distribution, spatial scale, such as quantum teleportation experiment. Current quantum satellite launch preparations are almost complete.

(Editors: Liu Cheng UN649)
2016-08-16 01:26:18
Modern gold

中国将发射全球首颗量子科学实验卫星

在酒泉卫星发射中心，星罩组合体吊装，与运载火箭对接 新华社发

“墨子号”在进行测试

“墨子号”在与运载火箭适配器对接

　　量子是个特别严肃、但很容易搞得不严肃的高深话题。中国的量子科学实验卫星“墨子号”即将发射，铺天盖地的报道让不少人都能把这当做茶余饭后的谈资。

　　不过，恐怕没人敢拍着胸脯说自己精通量子论，连当年创立和发展量子论的物理学大佬们都觉得这玩意儿难懂，普通人就不用说了。

　　与经典物理学和其他许多学科不同，量子论特别违反常识和直觉。一些看似不关联的现象竟能结合成一体，让人哭笑不得，如此无厘头的理论，如何理解？

　　据新华社北京8月15日电

　　量子纠缠 爱因斯坦的纠结

　　量子是物理世界里事物的最小份额。在数学上，你尽可以把东西分成一半又一半，没完没了地缩小下去，但物理的东西不能比一个量子更小了，不妨说整个世界都是量子组成的。

　　量子论作出的许多预测都得到了验证，没有量子论，就理解不了半导体材料的原理，造不出微小的晶体管，不会有集成电路，也就不会有电脑、手机和网络。

　　量子论的地位早已稳固，有一大堆物理学家靠它吃饭，但量子世界的某些根本问题，仍是他们共同的困扰。其中最要紧的一个，就是令爱因斯坦纠结多年、今天大家还在纠结的“超距作用”，它正是量子通信的基础，也是量子科学实验卫星要检验的问题，其正式称谓是“纠缠”。

　　两个处于纠缠中的粒子，彼此间存在一种神秘关联，即使相隔整个宇宙，只要纠缠不被打破，这种关联就存在着。量子纠缠那神秘的超距作用，让许多最优秀的人类头脑深感困扰。

　　人类似乎生来就认为定域性原则才是理所当然的，即一个物体只能受到周围事物的直接影响，远处的东西要借助媒介、跨越空间才能对它产生作用。要把桌上的咖啡杯端起来，就得伸手去拿。我对你喊话，声音通过空气的振动来传递。

　　量子纠缠则意味着，要么量子论存在漏洞，要么定域性原则可以违反。而以爱因斯坦为代表的部分物理学家则对超距作用的存在持怀疑态度，只认为量子理论是“不完备”的，纠缠的粒子之间存在着某种人类还没观察到的相互作用或信息传递，也就是“隐变量”。

　　物理学家约翰·贝尔设计了一套实验原则，把量子纠缠之争的战场从理论转移到了实验室。贝尔在感情上站在爱因斯坦一方，但这不影响其理论——人称“贝尔不等式”——的客观性。几十年来，科学家用光子、原子、离子等东西做了许多实验，结果都偏向量子论一方:没有隐变量的存在，量子态的纠缠是非定域性的。

　　不过贝尔设计的实验是假想实验，现实中很难完全满足实验原则的要求，迄今还没有一个实验可靠到能盖棺定论。扩大实验距离，正是消除漏洞的手段之一，量子科学实验卫星可以把实验距离扩大到前所未有的程度，有希望得出更加可信的结果。当然，将来如果能把实验的另一端设在月球甚至火星上，就更理想了。

　　量子通信 “不可拦截”的密钥

　　量子科学实验卫星的另一个任务是进行量子通信实验，这是量子纠缠应用领域中比较接近现实的一个。它的要点是特别安全，传统窃听手段原则上对量子通信没有用。加密的信息好比上了锁的箱子，用特定的钥匙才能打开。以当前的加密技术，只要付出足够的努力，钥匙理论上是可以拦截到的，只看效率高不高罢了。

　　而量子纠缠则提供“不可拦截”的钥匙。做法是并不刻意防止别人窃取钥匙，而是一旦有人这么干，通信双方必然能察觉。量子卫星制造两个纠缠的光子，分别发给通信的双方。双方对各自接收到的光子进行随机检测，用明文通信对比检测结果，看看两个光子是不是纠缠的。如果有人中途拦截光子，其观察行为会破坏纠缠状态，让钥匙作废——你偷呗，偷到就没用了，我换把新钥匙。

　　从理论到实践尚有很多技术困难，但总的来说，量子通信还是比传统通信安全得多，可能会给加密技术带来革命性的变化。近年来量子通信已经有一些小规模应用，中国发射这颗卫星是要率先搞个大动作，着手建设全球范围的量子通信网。有外媒评论说，这是“将顶尖研究转化为中国的全球力量战略资产的一个里程碑”。

　　量子计算 魔法般的高速计算

　　量子纠缠还有一个更了不起、但也更遥远的应用领域:量子计算。传统计算机离它的理论极限似乎已经不远，其中既有物理学导致的硬件局限，也有算法方面的软件局限。对一些运算量特别巨大的问题，传统计算机需要消耗的时间长到人类等待不起，甚至宇宙都等不起，目前看来量子计算机是唯一可能的出路，它会比传统计算机快亿万倍。

　　传统计算机算法基础是0或1的状态，而量子计算机则可以实现“既是1又是0”，多个纠缠在一起的量子比特能同时实现指数级别递增的运算威力，轻易碾压传统并行计算。

　　当然，研究还处在非常基础的阶段，很多问题尚待解答:用什么制作量子比特？怎么让它们维持那脆弱而短暂、特别容易遭到干扰的量子态？怎么对它们进行编程？制造量子计算机是不是需要有别于传统计算机的全新思路？用传统计算机发展历史来比拟的话，量子计算大概处于还在研发真空管的时代，让我们等吧……

　　●链接

　　它为啥叫“墨子号”？

　　记者15日从中科院获悉，中国即将发射的全球首颗量子科学实验卫星被命名为“墨子号”。

　　“关于这颗卫星的命名，我们考虑了好久。”量子科学实验卫星首席科学家潘建伟院士说，最终命名为墨子，缘起于已故著名教育家、中国科学技术大学老教授钱临照。

　　据了解，钱临照作为老一辈光学、科技史研究者，早年对墨家经典著作《墨经》有过深入研究，发现其中有不少与现代科学知识相通的记载，比如墨子在《墨经》中提出的“光学八条”。

　　“墨家逻辑是全球三大古老逻辑体系之一，而逻辑体系是科学的基础。”潘建伟说，墨子在两千多年前就发现了光线沿直线传播，并设计了小孔成像实验，奠定了光通信、量子通信的基础。

　　“就像国外有伽利略卫星、开普勒望远镜一样，以中国古代伟大科学先贤的名字来命名全球首颗量子卫星，将提升中国的文化自信。”他说。

　　据了解，作为中科院空间科学战略性先导专项首批科学卫星之一，量子科学实验卫星将在国际首次开展星地高速量子密钥分发、空间尺度的量子隐形传态等多项实验。目前量子卫星发射前的准备工作已基本完成。

(责任编辑：刘盛钱 UN649)
2016-08-16 01:26:18
现代金报