北京时间6月15号凌晨，SCIENCE杂志发表了我国墨子号量子卫星的第一个实验测试结果。自去年八月墨子号升空以来，在不到一年的时间里，就取得如此轰动的研究成果，彰显了我国的在量子信息领域的科研实力，也再次证明国家在这个方向的大手笔投入是可见成效的。事实上，这一成果不仅仅是属于中国人的，也是属于全世界的，是人类向量子物理科学的信息应用方面的一次集体进军。在世界范围内，从事该领域工作的研究人员对我国量子卫星的实验结果都表达了不同形式的期盼。那么此次量子卫星的研究成果究竟做了什么事情呢，我们一起来读一下SCIENCE杂志在同期的新闻里怎么说的 [1]-http://www.sciencemag.org/news/2017/06/chinas-quantum-satellite-achieves-spooky-action-record-distance
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China's quantum satellite achieves 'spooky action' at record distance
中国量子卫星实现了‘魅影’距离的记录
"It's a huge, major achievement," says Thomas Jennewein, a physicist at the University of Waterloo in Canada. "They started with this bold idea and managed to do it."
Thomas Jennewein评论说：“巨大而轰动的成就”，“他们从零开始！他们做到了！”（Thomas也是Aton Zeilinger组里出来的，现在在加拿大倡导量子卫星相关的实验研究！）
Entanglement involves putting objects in the peculiar limbo of quantum superposition, in which an object's quantum properties occupy multiple states at once: like Schrödinger's cat, dead and alive at the same time. Then those quantum states are shared among multiple objects. Physicists have entangled particles such as electrons and photons, as well as larger objects such as superconducting electric circuits.
量子纠缠是量子叠加，BALABALA.......
Theoretically, even if entangled objects are separated, their precarious quantum states should remain linked until one of them is measured or disturbed. That measurement instantly determines the state of the other object, no matter how far away. The idea is so counterintuitive that Albert Einstein mocked it as "spooky action at a distance."
爱因斯坦说量子纠缠是“时空中的魅影”，BALABALA......
Starting in the 1970s, however, physicists began testing the effect over increasing distances. In 2015, the most sophisticated of these tests, which involved measuring entangled electrons 1.3 kilometers apart, showed once again that spooky action is real.
实验人员从1970年代开始做实验（那个人叫Alan Aspect）。2015年发表在Nature上的1.3公里“魅影”验证，再一次（更完备）证明了它的准确性。
Beyond the fundamental result, such experiments also point to the possibility of hack-proof communications. Long strings of entangled photons, shared between distant locations, can be "quantum keys" that secure communications. Anyone trying to eavesdrop on a quantum-encrypted message would disrupt the shared key, alerting everyone to a compromised channel.
除了在基础研究中的重要性，量子纠缠可以用来产生‘量子密钥’，BALABALA......
But entangled photons degrade rapidly as they pass through the air or optical fibers. So far, the farthest anyone has sent a quantum key is a few hundred kilometers. "Quantum repeaters" that rebroadcast quantum information could extend a network's reach, but they aren't yet mature. Many physicists have dreamed instead of using satellites to send quantum information through the near-vacuum of space. "Once you have satellites distributing your quantum signals throughout the globe, you've done it," says Verónica Fernández Mármol, a physicist at the Spanish National Research Council in Madrid. "You've leapfrogged all the problems you have with losses in fibers."
损耗、损耗、损耗，重要的事情说三遍；于是我们有了‘量子中继’的方案
看图，不说话。
JianWei Pan, a physicist at the University of Science and Technology of China in Shanghai, got the chance to test the idea when the Micius satellite, named after an ancient Chinese philosopher, was launched in August 2016. The satellite is the foundation of the $100 million Quantum Experiments at Space Scale program, one of several missions that China hopes will make it a space science power on par with the United States and Europe.
（潘老师说话了）大致就是说我们的卫星造价1亿美金，我们每个人基本都花了5毛钱，这钱花的还是值当。
In their first experiment, the team sent a laser beam into a light-altering crystal on the satellite. The crystal emitted pairs of photons entangled so that their polarization states would be opposite when one was measured. The pairs were split, with photons sent to separate receiving stations in Delingha and Lijiang, 1200 kilometers apart. Both stations are in the mountains of Tibet, reducing the amount of air the fragile photons had to traverse. This week in Science, the team reports simultaneously measuring more than 1000 photon pairs. They found the photons had opposite polarizations far more often than would be expected by chance, thus confirming spooky action over a record distance (though the 2015 test over a shorter distance was more stringent).
实验地点在德令哈和丽江，当然还有天上。BALABALA......。这次在SCIENCE，研究团队报道了同时测量了超过1000对光子（这句话理解不到，抱歉）BALABALA......。主要是在1200公里上验证了‘魅影’，尽管和2015年的1.3公里相比，论证不那么严格。
The team had to overcome many hurdles, including keeping the beams of photons focused on the ground stations as the satellite hurtled through space at nearly 8 kilometers per second. "Showing and demonstrating it is quite a challenging task," says Alexander Ling, a physicist at the National University of Singapore. "It's very encouraging." However, Ling notes that Pan's team recovered only about one photon out of every 6 million sent from the satellite—far better than ground-based experiments but still far too few for practical quantum communication.
研究团队克服很多困难，BALABALA......。
Pan expects China's National Space Science Center to launch additional satellites with stronger and cleaner beams that could be detected even when the sun is shining. (Micius operates only at night.) "In the next 5 years we plan to launch some really practical quantum satellites," he says. In the meantime, he plans to use Micius to distribute quantum keys to Chinese ground stations, which will require longer strings of photons and additional steps. Then he wants to demonstrate intercontinental quantum key distribution between stations in China and Austria, which will require holding one half of an entangled photon pair on board until the Austrian ground station appears within view of the satellite. He also plans to teleport a quantum state—a technique for transferring quantum-encoded information without moving an actual object—from a third Tibetan observatory to the satellite.
潘老师希望我们再发一个更强悍的量子卫星，这样就可以在有太阳的情况下也可以玩实验了，BALABALA......。中国和维也纳将会一起来做量子密钥实验，BALABALA......
Other countries are inching toward quantum space experiments of their own. Ling is teaming up with physicists in Australia to send quantum information between two satellites, and the Canadian Space Agency recently announced funding for a small quantum satellite. European and U.S. teams are also proposing putting quantum instruments on the International Space Station. One goal is to test whether entanglement is affected by a changing gravitational field, by comparing a photon that stays in the weaker gravitational environment of orbit with an entangled partner sent to Earth, says Anton Zeilinger, a physicist at the Austrian Academy of Sciences in Vienna. "There are not many experiments which test links between gravity and quantum physics."
其他国家也要有自己的量子卫星，BALABALA......。“目前，还没有什么实验验证了量子物理和引力之间的关联”！（这会是一个诺贝尔奖级别的工作，这也是大家花钱真正要买的单！ ）
The implications go beyond record-setting demonstrations: A network of satellites could someday connect the quantum computers being designed in labs worldwide. Pan's paper "shows that China is making the right decisions," says Zeilinger, who has pushed the European Space Agency to launch its own quantum satellite. "I'm personally convinced that the internet of the future will be based on these quantum principles."
Zeilinger最后压轴出场说话了：“潘老师的文章表明中国做了一个正确的决定”。（Zeilinger的门生是量子卫星实验的主力军）。
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