Teleportation — Why it is important for the future of communication
Teleportation as we know it from science fiction movies probably will remain an impossible to achieve goal. But the technology itself is already real and a big part of quantum information research. Although it might only work on small scales, it will soon change the way we share information and communicate in networks.
It always starts with a small step. Just like in the year 1900, when Max Planck proposed that the black body radiation problem could be solved, if one sees energy as something discrete instead of something continuous. He called it quantized energy. This simple assumption led to the development of a scientific field which turns out to be a weird way of seeing reality. At least the microscopic reality. Because it contradicts everything we are used to from our everyday life physics. Quantum physics is a strange physical model to explain and predict the behavior of microscopic particles. And microscopic particles can do very strange things. The most famous example must be the double slit experiment. This experiment showed that quantum particles could be in 2 physical states at the same time and pass through both slits simultaneously. This eventually creates an interference pattern on a screen behind the slits, which makes physicists think that microscopic particles behave like waves.
Strange to imagine a particle as a wave, isn’t it?
Quantum particles can be in many physical states simultaneously.
Entanglement
Another quite peculiar consequence of the laws of quantum physics is the so-called entanglement. Just this year the nobel prize was given to researchers, whose work was mainly based on the nature of entanglement. You can read about it in my article “The physics nobel prize 2022”.
What happens to one entangled particle instantaneously triggers an action in the entangled partner particle.
Two particles can be entangled. We can deliberately put them into an entangled state. That means that those two particles are now connected with each other. Connected in a very special way. What happens to one particle influences what happens to the other particle. The crazy part is that this influence happens instantaneously. Which means that if something happens to particle A then particle B will instantaneously “feel” that and react to that; and Einstein did not really like this nor could he accept this as a physical reality. But why is that?
To answer that question we should first meet Alice and Bob. Those two love to participate in quantum and cryptography experiments. Alice has an electron and Bob has an electron. They entangle their electrons which means that they are now in this special connective state. Now Alice takes her electron onto an expedition to Mars. In the meantime neither her nor Bob are interacting with that qubit. Once she arrived on Mars she sends Bob a message, telling him to do something to the qubit. The message takes 3 minutes to go from Mars to earth, since the speed of light is only 300.000 kilometers per second. The second Bob receives the message he interacts with his electron. And without the slightest delay Alice’s electron reacts. As if the information between them has been mediated with a speed greater than light. And that kind of information transfer contradicted Einstein’s theory of relativity, which stated that nothing can be faster than the speed of light. This made him think that something is not quite right about quantum theory. But it turned out that entanglement is indeed reality and it even plays a big role in the realm of quantum computing. But more importantly: it plays a big role in teleportation.
Teleportation
So how does teleportation actually work?
When we talk about teleportation in the terms of quantum physics, we mean that we transfer the information contained in the quantum state of a particle from one place to another.
Because this sounds quite complex, we once again engage Alice and Bob in an experiment.
The foundation of teleportation is entanglement.
So let’s say Alice has an electron and wants to teleport it to Bob. But it’s not like the electron just jumps through space instantaneously to wherever Bob is waiting. Alice is taking all the information that makes up her electron and sends the information to Bob. This includes parameters like electric charge, mass and spin. Bob needs a neutral electron functioning as a blank paper, so he can “print” the information of Alice’s electron onto it. In order for this to work Bob’s electron needs to be entangled with Alice’s electron.
Bob receives the information from Alice via a so called classical channel. A classical channel is a term used by quantum physicists to describe all common ways of communicating information that we nowadays use. This includes anything you can imagine like a telephone line, a radio transmission or a sequence of 1’s and 0’s on a piece of paper. A quantum channel would be a way of transmitting quantum information. Those channels are for example used in superdense coding, another fancy quantum algorithm. But let’s go back to Alice and Bob.
So Alice took all the information of her electron and sent it via radio waves to Bob. He receives the sequence of 1’s and 0’s and imprints the information onto his blank electron. This way he recreated the exact electron, that Alice had on the other side. Let’s see how that would apply to humans — just for fun and purely theoretical.
So in order for a person to be teleported, every single particle in the person’s body must be entangled with a particle of the same type on the other side of the teleportation channel. Then every single particle’s quantum state must be exactly encoded into a sequence of 1’s and 0’s. That’s a lot of data. And this huge amount of data then has to be transferred — without loosing a single bit — to the other side. There the information will be decoded and imprinted onto the entangled partner particles. So if Alice is teleporting herself to the place where Bob stays, she first needs to entangle every single particle in her body with particles at Bob’s spot, which must be exactly the particles she is existing of. This information creates another Alice on Bob’s side. The question you may ask yourself now is: What happened to the original Alice? Is she still there?
The No-Cloning Theorem
Well I think the title of this section already answered the question we asked ourselves at the end of the last section. But let’s find out why that is, shall we? In order to do so, we have to take a look again at the double slit experiment, which we mentioned at the beginning of this article. There we saw how electrons are in a quantum state and can pass through both slits at the same time. But what happens if we want to see how it passes through both slits at the same time?
We could install a detector behind the wall with the 2 slits. The detector would register, which slit the electron has passed through. But once that detector is activated, the electron no longer behaves like a wave. It does not want to be observed. Observations destroy quantum states. The electron passes through only one of the slits and eventually no interference pattern will appear.
Observations destroy quantum states.
Back to the teleportation protocol. If we extract the information out of a particle, we have to measure the information somehow. And by doing so we destroy the quantum state. So it is impossible to create an exact replica of a particle while the original one still exists unchanged.
This is known as the No-Cloning Theorem.
A quantum state cannot be copied without destroying the original one.
Applying this to Alice’s teleportation process, we will notice that as long as her information is being transported, she does not exist in physical form. She is just pure information.
Only when the information has been completely imprinted on the waiting blank particles, she again exists in physical form. Kind of creepy, isn’t?
I find that creepy.
But anyway.
How is that now related to communication technology?
The future of communication
One of the biggest applications of the quantum laws will be quantum computers. Given enough qubits to process information they are said to become more powerful than any classical computer nowadays could ever be.
Now imagine a network of quantum computers and what they could do. Amazing right?
Since quantum computers process quantum information, in a network of quantum computers this quantum information needs to be exchanged between the network nodes. But because of the No-Cloning Theorem the quantum information cannot be transferred just like in classical networks. This is where teleportation enters the game. In a network of quantum computers — a quantum internet if you will — the quantum information is being transferred in between the nodes via the teleportation process.
So what’s the use of all that? Why would we need a quantum internet and how is it related to communication?
Well, the crazy part is that in such a quantum network we could establish a communication channel which is impossible to eavesdrop. Why?
Because of the influence that observation has on quantum states.
If you eavesdrop information that is being transferred in between two points, you measure the quantum state and you unavoidably change the information. This is how the information stays safe and the eavesdropper is being noticed and located.
So you can see that quantum teleportation — although it sounds like a crazy science fiction concept — is indeed a real thing, just not in the sense we imagined it in the beginning. And most amazingly: It will be used to establish a more secure way of exchanging information.
Thanks for staying with me until the very end. I hope you enjoyed reading this article and you could learn something new. Leave a clap if you liked what you read and leave me a comment below! :)
Subscribe to DDIntel Here.
Visit our website here: https://www.datadriveninvestor.com
Join our network here: https://datadriveninvestor.com/collaborate
