China Quantum Communiations Technology: Cryptography, Radar, Satellite, Teleportation, Network

[Beny Karachun]

China has launched the first satellite for quantum communications, Mozi, into a 600km sun-synchronous orbit. The satellite is designed to facilitate transmission of entangled photons from a ground station in Beijing to one in Vienna; this would allow quantum key encrypted communications over about 7,000km, versus the current record of a few hundred kilometres over fibre. The satellite is also intended to demonstrate quantum teleportation over this distance, again compared to current records of a few hundred kilometres. According to one of the physicists on the team, the satellite could be followed by others if successful, allowing transmission of quantum information across the globe.

http://forum.kerbalspaceprogram.com/index.php?/topic/145987-quantum-science-satellite-mozi/

Thanks

 

[Viet]

ANYONE want to know wha it really is, just read the following articles if you can understand.

the main author J. W. PAN is also the leader of this project (Quantum communication).

1：JWPan,ZBChen,MZukowski,HWeinfurter,AZeilinger， Multi-photon Entanglement and Interferometry，Reviews of Modern Physics 2012.[22]
2：ZSYuan,XHBao,CYLu,JZhang,CZPeng,JW Pan，Entangled Photons and Quantum Communication，Physics Reports,2010,497:1.
3：ZSYuan,YAChen,BZhao,SChen,JSchmiedmayer,JWPan,Experimental Demonstration of a BDCZ Quantum Repeater Node，Nature,2008,454：1098.
4：YAChen,SChen,ZSYuan,BZhao,CSChu,JSchmiedmayer ,JWPan ，Memory-built-in Quantum Teleportation with Photonic and Atomic Qubits,Nature Physics,2008,4:103~107.
5：ZZhao,YAChen,ANZhang,TYang,HBriegel,JW Pan，Experimental Demonstration of Five-photon Entanglement and Open- destination Quantum Teleportation，Nature,2004,430:54.
6：DBouwmeester,JWPan,KMattle,MEibl,HWeinfurter,AZeilinger,Experi mental Quantum Teleportation，Nature,1997,390：575.
7：JWPan,DBouwmeester,HWeinfurter,AZeilinger，Experimental Entanglement Swapping: Entangling Photons that Never Interacted，Physical Review Letters,1998,80：3891.
8：JWPan,DBouwmeester,MDaniell,HWeinfurter,AZeilinger， Experimental Test of Quantum Nonlocality in Three-Photon Greenberger-Horne- Zeilinger Entanglement，Nature,2000,403：515.
9：JWPan,CSimon,CBrukner,AZeilinger，Entanglement Purification for Quantum Communication，Nature,2001,410：1067.
10：JWPan,SGasparoni,MAspelmeyer,TJennwein,AZeilinger， Experimental Realization of Freely Propagating Teleported Qubits， Nature,2003,421:721.
11：JWPan,SGasparoni,RUrsin,GWeihs,AZeilinger，Experimental Entanglement Purification of Arbitrary Unknown States，Nature,2003,423:417.
12：WPhilip,JWPan,MAspelmayer,RUrsin,SGasparoni,AZeilinger,A four-photon Young s Double-slit Experiment，Nature,2004,429:158.[1]

I would appreciate if any chinese poster here can explain how it works in principle to the audience, in ONE page, and not after graduating in physics, computer science and telecommunications. and after reading 12 books you listed

 

[yusheng]

in fact, this time, the experiment is only to test the tech applied in the fields, it is not the basic sciences experiement, don't need to reveal any secrets of the nature.

quantum physics is controversial itself， but this doesn't prevent us using quantums though they are elusive.

 

[Viet]

one of his article:

Quantum teleportation of multiple degrees of freedom of a single photon

Abstract
Quantum teleportation provides a 'disembodied' way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication, distributed quantum networks and measurement-based quantum computation. There have been numerous demonstrations of teleportation in different physical systems such as photons, atoms, ions, electrons and superconducting circuits. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom--internal and external--and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin-orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.

that text is for students enrolled in university. I doubt anyone outside the subject understands it.

in fact, this time, the experiment is only to test the tech applied in the fields, it is not the basic sciences experiement, don't need to reveal any secrets of the nature.

quantum physics is controversial itself， but this doesn't prevent us using quantums though they are elusive.

the problem with made in china quantum communications is: nothing is revealed. nothing is explained. a blackbox. I expect at least Chinese would reveal what technology they use by creating photons, splitting photons, seting them in entangled state, encoding the particles before sending them via glass fibre or satellite to the opposite site.

 

[yusheng]

yes, that is why i know my limitations, i will not wish other to help me but study hard by myself.

 

[ahojunk]

ANYONE want to know wha it really is, just read the following articles if you can understand.

the main author J. W. PAN is also the leader of this project (Quantum communication).

1：JWPan,ZBChen,MZukowski,HWeinfurter,AZeilinger， Multi-photon Entanglement and Interferometry，Reviews of Modern Physics 2012.[22]
2：ZSYuan,XHBao,CYLu,JZhang,CZPeng,JW Pan，Entangled Photons and Quantum Communication，Physics Reports,2010,497:1.
3：ZSYuan,YAChen,BZhao,SChen,JSchmiedmayer,JWPan,Experimental Demonstration of a BDCZ Quantum Repeater Node，Nature,2008,454：1098.
4：YAChen,SChen,ZSYuan,BZhao,CSChu,JSchmiedmayer ,JWPan ，Memory-built-in Quantum Teleportation with Photonic and Atomic Qubits,Nature Physics,2008,4:103~107.
5：ZZhao,YAChen,ANZhang,TYang,HBriegel,JW Pan，Experimental Demonstration of Five-photon Entanglement and Open- destination Quantum Teleportation，Nature,2004,430:54.
6：DBouwmeester,JWPan,KMattle,MEibl,HWeinfurter,AZeilinger,Experi mental Quantum Teleportation，Nature,1997,390：575.
7：JWPan,DBouwmeester,HWeinfurter,AZeilinger，Experimental Entanglement Swapping: Entangling Photons that Never Interacted，Physical Review Letters,1998,80：3891.
8：JWPan,DBouwmeester,MDaniell,HWeinfurter,AZeilinger， Experimental Test of Quantum Nonlocality in Three-Photon Greenberger-Horne- Zeilinger Entanglement，Nature,2000,403：515.
9：JWPan,CSimon,CBrukner,AZeilinger，Entanglement Purification for Quantum Communication，Nature,2001,410：1067.
10：JWPan,SGasparoni,MAspelmeyer,TJennwein,AZeilinger， Experimental Realization of Freely Propagating Teleported Qubits， Nature,2003,421:721.
11：JWPan,SGasparoni,RUrsin,GWeihs,AZeilinger，Experimental Entanglement Purification of Arbitrary Unknown States，Nature,2003,423:417.
12：WPhilip,JWPan,MAspelmayer,RUrsin,SGasparoni,AZeilinger,A four-photon Young s Double-slit Experiment，Nature,2004,429:158.[1]

,
@yusheng

Thank you for this list.

To be honest, I have a headache just skimming through the list. (I was not even reading!)

Come on, are there others who felt the same?

 

[yusheng]

,
@yusheng

Thank you for this list.

To be honest, I have a headache just skimming through the list. (I was not even reading!)

Come on, are there others who felt the same?

i just playing with some trolling, dont take it seriously.

it is happy to see, with Chinese scientific development, more and more foreigners can not follow.

 

[Viet]

yes, that is why i know my limitations, i will not wish other to help me but study hard by myself.

ok I give you a hint: the classical approach to secure communications as we know it today is RSA, AES and DH. these are well-known cryptography technology, with asymmetric and symmetric encryption keys, key exchange, certs, hash function. all base on the promise, even the information are captured by intruders, it is impossible to decode it because of mathematical complexity and difficulty. even supercomputers need years to find out the secret key (if using high number of bits).

quantum communications uses a different approach. it relies on the premise, it is impossible for intruders to copy photon entangle states in order to decode the key, rather than mathematical complexity.

 

[TaiShang]

that text is for students enrolled in university. I doubt anyone outside the subject understands it.


the problem with made in china quantum communications is: nothing is revealed. nothing is explained. a blackbox. I expect at least Chinese would reveal what technology they use by creating photons, splitting photons, seting them in entangled state, encoding the particles before sending them via glass fibre or satellite to the opposite site.

Obviously, it is advanced tech. I am not sure there are posters here who can do all the tricky explanations in one simple page. I am not one of them, at least I know that.

As for China not sharing any data, news are coming in bit by bit, but I am sue there are lots of considerations as to what to share and what not to share.

If China bans certain drones or supercomputer tech to be imported, I am sure China also not extra willing to reveal every bot of knowledge it discovers.

Most likely, we will see the results, not the way how it is done.

 

[Viet]

Obviously, it is advanced tech. I am not sure there are posters here who can do all the tricky explanations in one simple page. I am not one of them, at least I know that.

As for China not sharing any data, news are coming in bit by bit, but I am sue there are lots of considerations as to what to share and what not to share.

If China bans certain drones or supercomputer tech to be imported, I am sure China also not extra willing to reveal every bot of knowledge it discovers.

Most likely, we will see the results, not the way how it is done.

no I don´t expected detailed technical drawings, but some technical hints how Chinese quantum communication is built. otherwise I believe it is difficult to assess a blackbox.

 

[xunzi]

Let revolutionize how we will process our data in the future. I expect every advance nation to follow suit and make it more safer from the US teardrop. Germany is one of the country really need of this tech so they should work with us.

 

[Viet]

Let revolutionize how we will process our data in the future. I expect every advance nation to follow suit and make it more safer from the US teardrop. Germany is one of the country really need of this tech so they should work with us.

You live in a dream world. The likelihood Germany using Chinese encryption technology is Zero. It is not like buying cheap solar panels.

 

[yusheng]

@九维空间Sturman 还透露，25日，兴隆站和量子卫星成功激光光束对接，26日晚，阿里站和量子卫星成功激光光束对接。这种对接有多难：500km的轨道高度，第一宇宙速度，200mm口径的望远镜，难度相当于你站在五十公里以外把一枚一角硬币准确地扔进一列全速行驶的高铁上的一个矿泉水瓶里！
　　据量子科学实验卫星首席科学家潘建伟此前介绍，“墨子号”承担着发射和传输光信号的重要任务，要想保证距离地球表面数百公里的光信号能够顺利被地面光学天线接收，难度就好比是“针尖对麦芒”一样。
　　他解释说，由于卫星发射的光信号是极其微弱的单光子级别，在由空间向地面传输的过程中会受到许多因素的干扰，比如星光、灯光等都将成为干扰信号传输的背景噪声。此外，卫星的运动速度很快，地面的光学天线必须时刻紧跟卫星的“节奏”才有可能实现信号的准确接收。所以，在“墨子号”量子通信卫星的设计过程中，不仅要克服各种噪声的干扰保证信号源的稳定，同时还要实现与地面光学天线的准确对接。尽管是如同“针尖对麦芒”般苛刻的实验条件，但是在我国科学家的不懈努力下，如此不可思议的技术难题也依然得到了解决。
　　8月16日1时40分，我国在酒泉卫星发射中心用长征二号丁运载火箭成功将“墨子号”发射升空。
　　“墨子号”量子卫星是中国科学院空间科学先导专项首批科学实验卫星之一，其主要科学目标是借助卫星平台，进行星地高速量子密钥分发实验，并在此基础上进行广域量子密钥网络实验，以期在空间量子通信实用化方面取得重大突破；在空间尺度进行量子纠缠分发和量子隐形传态实验，开展空间尺度量子力学完备性检验的实验研究。

 

[jkroo]

Let's cheer the quantum technology feat.
Don't be surprise for the quantum chips you guys will see soon. Quantum computer is just on the way.

A quantums research team from China just finished 600 pairs quantums experiment. A very very huge computing capacity can be reached.

 

[xunzi]

You live in a dream world. The likelihood Germany using Chinese encryption technology is Zero. It is not like buying cheap solar panels.

Wait until we revolutionize quantum communication than you will see Berlin come knocking on our door. In fact, they already did. LOL