【故国神游】中国量子通信发展

量子通信原理简图：

如果你发现同一光子在不同地方同时出现，你就登了量子之堂。如果你看到一只猫＊同时生又同时死，你就入了量子不确定性之室。量子的不确定性，保障了量子通信的密传——因为窃取信息者会破坏量子的不确定性，所以窃取量子信息就几乎是不可能的了（注意“几乎”二字）。较新的量子理论，提出一树衍生繁枝的多宇宙观（這使量子计算变得更加有趣而惊人），又提出物质超越光速的可能(直接挑战爱因斯坦)。


2016年8月中国发射了一枚量子通信实验卫星。可是，中方只是非常笼统地介绍实验内容，外界难作具体评估。当然，中方可能基于战略理由，不公布详情。总之，据称量子信息顺利得到交传（entanglement)——即是长距如无距（确是成功的话），尽管我们不知其信息量如何。


有意思的是、中国首席量子物理学家潘建伟公开说过：卫星试验并非意味量子通信的突破时刻来临了。然而，北京依旧咬定“突破”二字来概括中国的量子科技成就，唯是只字不提潘说。


--- 寒苇


＊Schrödinger's cat (维基有科普介绍)

所有跟帖： 

• 玄！ -lovecat08- ♀ (0 bytes) () 06/30/2023 postreply 13:37:08

• 量子物理学可以说是后爱因斯坦时代的 paradigm shift. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 13:58:32

• 量子力学 与老爱的相对论 构成了现代物理学的基础。寒兄的“后爱因斯坦时代的 paradigm shift” 如何理解？ -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 14:04:41

• 较新的量子理论，提出一树衍生繁枝的多宇宙观，这使量子计算变得更加有趣而惊人，又提出物质超越光速的可能，直接挑战爱因斯坦。 -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:09:01

• 量子计算， 量子计算机是非常热的课题。但量子卫星 有些像：欲炼神功，必先自宫了：） -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 14:17:08

• Paradigm, 中译是“范例”。好像不太贴切。 -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:07:01

• +100 在听天书 -颤音- ♂ (0 bytes) () 06/30/2023 postreply 14:20:31

• 科普有趣。 -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:08:37

• 我在这方面只能“神游”了！ -花似鹿葱- ♀ (0 bytes) () 06/30/2023 postreply 13:40:12

• 对物理学来说，想像力是不可或缺的。 -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:00:44

• 喜欢读科幻，同样喜欢读科普。 -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:09:52

• 量子卫星is a joke：）潘和我很熟，他吹牛在行：） -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 13:40:46

• 呵呵呵，无言发表！ -lovecat08- ♀ (0 bytes) () 06/30/2023 postreply 13:47:44

• I would rather suspend my judgement until I know better. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:03:07

• Indeed, we should never jump to conclusions. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:17:59

• 量子密码的根本问题没解决，破坏量子密码的成本远低于建立的成本。九十年代如此，今天亦然。潘是浪费国家资源。 -冯墟- ♂ (0 bytes) () 06/30/2023 postreply 14:49:12

• 谢谢！这是我这篇短文所表明的立场：不论基于何种原因，中国量子通信的所谓突破性发展，其实证尚有待公布。 -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 15:04:37

• 潘就此事没有说明，但他手下一员大将公开说了，没有突破。97年，我问过郭光灿。无进展。 -冯墟- ♂ (0 bytes) () 06/30/2023 postreply 15:13:01

• 不想在此作任何猜测，只想说，在今天我还沒看到有关公布。 -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 15:22:33

• 实验是检验真理的一个标准。 -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:31:13

• 这老兄的着眼点一直是发 Science 文章和评院士，实货可知。 -唐宋韵- ♂ (0 bytes) () 06/30/2023 postreply 14:55:41

• At last someone brought up quantum communication. -renqiulan- ♂ (0 bytes) () 06/30/2023 postreply 13:52:48

• 发射那个卫星是多余的：）quantum communication可在地面做：） -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 13:55:43

• You might want to keep an open mind on that. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:05:52

• 请寒兄讲得具体一些：）不要用太哲学化的语言：） -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 14:08:51

• https://www.technologyreview.com/2019/02/14/103409/what-is-q -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:13:28

• You want to dig deeper. Go check out the above article. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:14:38

• 请寒兄用自己的语言 描述问题：）LINK 就不看了：） -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 14:19:18

• 向西东先生推荐 Quantum (an online journal). 苇苇写的是科普短文。 -renqiulan- ♂ (0 bytes) () 06/30/2023 postreply 14:20:18

• 从讨论来看，I'm not sure if 寒兄真正理解了quantum computing, -西东人8- ♂ (156 bytes) () 06/30/2023 postreply 14:31:49

• Thank you.That's OK. You make your own conclusion. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:47:13

• So Qiulan is a fan of quantum communication. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:54:50

• Entanglement is not communication -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:06:08

• But entanglement is indeed the most amazing thing -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:09:29

• Entanglement is part & parcel of the communication process. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:11:33

• No info from A to B, just happend simultaneously -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:16:14

• +1 -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 14:19:51

• Sorry, I don't quite follow you. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:22:06

• Just like Trump & Biden, always say oppositely but no comm -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:24:21

• They are entangled -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:26:31

• How exactly? It must be quite a sight. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:00:02

• Pardon me. On what basis did you make the above claim? -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:27:26

• I'm truly interested in relevant experimental studies. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:28:50

• i maybe wrong about them but not about quntums, see inside -老键- ♂ (120 bytes) () 06/30/2023 postreply 14:35:56

• Thank you. Here is an opposite view for your reference: -寒苇- ♀ (174 bytes) () 06/30/2023 postreply 14:43:38

• Thx. Yes, it can be used in quntum communication -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:47:51

• There are always opposite views before the dust settles. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:03:52

• EPR "paradox" -冯墟- ♂ (0 bytes) () 06/30/2023 postreply 18:34:00

• 有趣的比喻。 -shuier- ♀ (0 bytes) () 06/30/2023 postreply 15:57:28

• I mearly state a fact, not against your post, sorry for that -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:44:54

• I don't own quantum communication. Neither do you. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:48:23

• Science is a fact-finding mission. That's the whole shebang. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:53:27

• Right. Truly sorry for the disruption -老键- ♂ (0 bytes) () 06/30/2023 postreply 14:55:40

• Not at all. Actually I'm glad that you did "interrupt" me. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 15:26:57

• Once in a while we need to pause & do some stocktaking. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 15:33:06

• 对啊，而且既然在书香，就要多从书里stocktaking。物理学很有意思，可以一起讨论些读物，不是指textbook -老键- ♂ (0 bytes) () 06/30/2023 postreply 16:11:32

• Such as "A Brief History of Time"? Or "Fluid Mechanics"? -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 16:46:02

• 真是哪壶不开拎哪壶啊 ：））最怕读时间简史了 -老键- ♂ (0 bytes) () 06/30/2023 postreply 17:35:53

• 苇苇 is a lady. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:10:08

• 老键 is a gentleman. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:08:42

• I always want to be a gentleman but not always is -老键- ♂ (0 bytes) () 06/30/2023 postreply 16:17:53

• You are a 100% gentleman. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:39:33

• Mr 老键 is a 100+% gentleman! -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 16:41:39

• 我有点关心量子计算机发展和它对加密系统可能的冲击。如果现行的RSA加密系统已岌岌可危，那么我们一定会看到美国政府、军方、 -唐宋韵- ♂ (57 bytes) () 06/30/2023 postreply 14:50:52

• Thank you! That's a topic for another day. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 14:54:53

• 寒兄是后生可畏！如有得罪之处，还望包涵：） -西东人8- ♂ (0 bytes) () 06/30/2023 postreply 15:00:32

• Thank you.I just wanted to take emotion out of the equation. -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 15:25:01

• Hi, Shuier! -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 16:22:30

• Yes, let's generate light rather than heat. -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:24:12

• That's well-meant and well-said. Thank you! -寒苇- ♀ (0 bytes) () 06/30/2023 postreply 16:28:43

• You are most welcome! -shuier- ♀ (0 bytes) () 06/30/2023 postreply 16:29:49

• 俺去年写过一首量子（力学）诗。 -AP33912- ♂ (0 bytes) () 06/30/2023 postreply 18:18:00

• 谢谢阿普。可以在书坛重发这个力学帖吗？ -寒苇- ♀ (0 bytes) () 07/02/2023 postreply 07:52:35

• 有一点误入歧途的感觉 -oudi87- ♂ (0 bytes) () 07/01/2023 postreply 09:53:07

• 不明白含义。无论如何，谢谢赐评！ -寒苇- ♀ (0 bytes) () 07/02/2023 postreply 07:54:35