China's Quantum Satellite and Einstein´s Disclaimed Testament

QUESS sattelite, Credit: Xinhua

Quantum Experiments at Space Scale (QUESS) spacecraft lifted off atop a Long March-2D rocket from the Jiuquan Satellite Launch Center in the Gobi Desert on Monday, August 15, 2016. Its objective is to test whether it is possible to develop a large capacity, unhackable communication network. It uses curious features of quantum particles, photons: superposition and quantum entanglement. The satellite will circle the Earth at an altitude of about 600 kilometres trying to teleport confidential information over 2000 kilometres away which is fifteen times more than the current record held by the European and American scientists. In collaboration with Europe, China intends to develop European and Asian quantum telecommunication network by the year 2020 and a worldwide quantum telecommunication network by the year 2030.

Long March-2D Launch, Credit: China Daily

The Chinese experimental satellite will test out the possibility to teleport quantum cryptographic keys for a considerably longer distance that it was achieved on the Earth´s surface. You may be surprised; however the quantum distribution of cryptographic keys is a service commercially available on the Earth´s surface. It is expensive, slow, for short distances only but incredibly safe. At present, there are at least four companies that are able to provide the quantum cryptographic network as a turnkey delivery. The most powerful quantum communication network is currently being tested in Japan.

Then why does China want to develop a quantum network infrastructure at the Earth´s orbit? It is related to the principle on which the quantum communication works.

Let us imagine that Alice wants to send a confidential message to Bob. At first she encrypts the message by a cryptographic key representing a chain of some hundreds of random letters and digits. And somehow she has to deliver the key to Bob. Since then Bob is able to read any kind of message encrypted by Alice. Delivery of the cryptographic keys is performed by the quantum communication networks.

But why should such expensive devices be used when this issue is reliably solved by the current cryptographic algorithms using private and public cryptographic keys? It is because the quantum communication networks are promising a unique feature.  Alice and Bod are able to find out whether their cryptographic key has not been read by a third person along the way. How is that possible?

As I have already mentioned before, the quantum cryptographic communication uses mostly photons to teleport information. Actually, their features. For example polarization. To make it more simple, let us assume that each photon can be present in three states only: in the state of horizontal polarization, in the state of vertical polarization and in the state of superposition. Each “newly born” photon is present in the state of superposition, e.g. it exists in both states: horizontal and vertical simultaneously. How can we imagine that? Take a coin, place it on its edge and flip it. It will be flipping on its edge. And it would flip forever if no friction of the air and desk surface. What would you say which side is the flipping coin on: heads or tails? Weird but the true answer would be: neither of them but both sides at the same time.

It is exactly the same with a photon being in superposition. Unless we start to measure it, we have no chance to know what state it is. If we try, it will end up in a stable state: horizontal or vertical polarization. As if we covered the flipping coin with a hand in one moment, move the hand away to see what side is the coin: heads or tails.

Moreover, the Chinese satellite uses another weird feature of the quantum world: quantum entanglement. I would say that it is the most curious characteristic that I have ever come across in my entire life. It is so curious that neither Einstein could believe it.

What is the quantum entanglement all about? Imagine we have a laser generating a stream of photons passing through a special crystal. Approximately one out of a billion splits into two - being quantum entangled. Since that moment they are going to behave as “twins”. Even if they were on the other side of the universe they will know everything about each other. Immediately.

Example. A collapse of one entangled photon to the horizontal polarization will cause the other end to be immediately programmed to collapse to the vertical polarization. Immediately. As if no law of the maximum speed of light applied to them. How is that possible?

Just imagine that both of the entangled photons are two “ends” of the same quantum formation passing through a wormhole. If one end collapses to a stable state, the other has to collapse to a compatible state. Otherwise it would violate the momentum conservation law. And, since they are in the wormhole a totally different space-time applies to them than to us. It is twisted to microscopic space.

A wormhole is a hypothetical physical feature predicted by Einstein´s theory of general relativity. It is a space-time tunnel, shortcut for long journeys across the universe. Wormholes are widely used in science fiction.

If you are already feeling dizzy from the quantum and relativistic terms which I have used - get used to it. It is nothing in comparison to what is about to come in near future. The world´s greatest masterminds of physics are right now feverishly verifying the previously mentioned hypothesis. The hypothesis of the century:

ER=EPR.

The abbreviation ER refers to Einstein, Rosen who described the phenomenon of wormholes in 1935. The abbreviation EPR refers to Einstein, Podolsky, Rosen who in the same year theorized about the phenomenon of quantum entanglement.

Credit: www.physics-astronomy.com

Please remember this “Einstein´s equation”. It is going to be as important as his E=mc2. This hypothesis claims that wormholes and quantum entanglement are expression of the same natural phenomenon. In case it proves to be correct, something amazing will happen. We will discover a unified physical theory of everything: quantum theory of gravity. This theory would, for example, allow us something what is beyond our imagination: targeted manipulation with space and time.

Let us go back to the quantum communication. Alice wants to send a cryptographic key to Bob using the Chinese satellite. How will she do that? The satellite will send two entangled photons to Earth. Both in the superposition state. One will be received by Alice, the other by Bob. At first, Alice will “encrypt” the first bit of the cryptographic key to its photon. At that moment Bob´s photon “knows“ to which state it will collapse once Bob is reading it. This procedure is being repeated, bit by bit, for the whole cryptographic key.

Credit: Xinhua

Okay, but how is the resistance against eavesdrop being assured? Let us imagine that Bob´s photon would be eavesdropped by a third party - Eva. Of course, she would be able to read the information from Alice. As well as Bob. However, the photon once read will no longer be entangled and in state of superposition. Eva can no longer use it for communication. She has to send a false one bringing a statistic error to the communication which can be detected by Alice or Bob.

And why do the Chinese bring the quantum communication to the orbit? As you can imagine from the previous text, quantum communication is dependent on delivery of every single photon. Even though the photon is rather resistant to “damage”, as every particle, it can sometimes collide with something on its journey: electron, other photon, atomic core. Each of these “dates” means loss of communication. The same as if Eva had read the message.

This significantly decelerates the quantum communication and makes it more expensive. So far, the scientists have been able to teleport a photon over 150 kilometres away. To teleport a photon over 2000 kilometres away assumes using a pretty brute force. For example, a large quantity of photons transmitted in parallel of which only a few will cross the finish line. In addition, the Chinese want to make use of the fact that with an ascending altitude the number of atmospheric gas molecules decreases. So when a photon is shot off from a sufficient altitude above the Earth´s surface it might meet fewer obstacles on its journey than a photon flying only a few meters above the Earth. And that is what the Chinese satellite is going to test and measure.

After GPS, permanently testing correctness of the theory of time deformation, the space quantum communication is going to be another technology that is going to test out even more curious features of the quantum world on a massive level.

For all skeptics this is going to be a clear evidence that reality is rather weird than normal, that we are headed to success by open mind rather than prejudice, and a change eventually brings more advantages than hides dangers.

Quite a decent contribution of the Chinese quantum satellite, don’t you think?