Quantum Teleportation- A faster than light communication breakthrough?
Let’s take a look at the phenomena of the quantum entanglement, crucial for teleporting data!
“They used to say that if Man was meant to fly, he’d have wings. But he did fly. He discovered he had to.” Captain Kirk.
For years, we have watched numerous sci-fi movies use teleportation for transport. Whether it was Mr Spock saving Captain Kirk or Nightcrawler saving the X-Men, we always wished we could experience it firsthand. The idea of disappearing from one place and appearing in another seems fascinating when compared to our daily lives. How many times have we wondered if we could teleport ourselves from our rooms to the classrooms and from there to some distant place to take a moment off? But is it actually possible in the harsh reality of our universe, limited by the laws of physics, for something so magical to happen?
When it comes to the macro-level or the physical world we live in, the answer is still a big NO. But that doesn’t stop us from exploring this mystic concept on the quantum scale. One of the cornerstones of quantum theory is entanglement, or the interaction of one particle with another regardless of the space separating them. With recent developments in understanding this spooky action-at-a-distance concept, we may have hit on something that brings us closer to transporting data without actually moving it.
Let’s rewind the clock a little!
For a long time, teleportation was confined to sci-fi movies and novels to woo or amaze audiences. Researchers never paid much heed to it, as it seemed to violate Heisenberg’s principle of uncertainty. This principle says that the more accurately you try to scan an object, the more you disrupt its state of being. In the end, you reach a point where the original state doesn’t even exist anymore. What’s worse, you don’t even get enough information to replicate the object in question. Makes the whole thing pointless, right?
Things took a different turn in 1993. A group of six scientists including IBM fellow Charles H. Bennett found a way around this problem. They used a paradoxical feature of quantum mechanics known as the Einstein-Podolsky-Rosen effect given in 1930.
A snippet of EPR paradox!
To understand what this actually is, let’s go about a century or so back. Heisenberg argued that a particle’s position or momentum was indefinite until you measured it. Einstein, Podolsky and Rosen devised a thought experiment to contradict him. They considered two particles in an entangled state, i.e one responds to the changes in the other. Now, if you were to measure the momentum of particle 1, entanglement will enable you to predict that of particle 2 also. This would happen even though you weren’t measuring for particle 2. According to Heisenberg, this sort of indirect measurement can’t yield results. Yet entanglement remained a fundamental feature of quantum theory and was afterwards proved. The ability of properties to be measured using entanglement is what constitutes the EPR paradox.
“God does not play dice.”–Albert Einstein
“Quit telling god what to do.”–Niels Bohr
How is it linked to teleportation though? Well, the basic ideas behind teleportation involve using entanglement to send information across a pair of linked quanta. In the following years, many experiments showed quantum teleportation with single photons, nuclear spins and trapped ions.
But things aren’t as easy as they seem: we can’t just scan information from one point and transfer to another, for the quantum world is a tricky place. Let’s break down the concept of teleporting a little, so we may try our hands at it as well xD
Before we head further, let’s learn a new word, which we are going to use a lot from now on — qubit. As a bit is the basic unit of information in a classical computer, a qubit is the basic unit of information in a quantum computer.
Understanding teleportation at its base:
Let’s consider body A, which we wish to teleport. Scan part of the information of A and send it to C directly (a body which has never been in contact with A). Send the rest to C using the EPR effect via an intermediary particle B. Here’s the catch, though. Particle B interacts first with C and then with A.
This is odd because unlike a regular delivery vehicle, which first goes to the sender and then the receiver, it happens the other way round. But that’s how EPR correlation or entanglement works. Later by applying a suitable treatment to C, it is possible to manoeuvre C into exactly the same state as A, before it was scanned. The crucial fact here is that A is itself no longer in that state, having been completely distorted by scanning, so what has been achieved is teleportation, not replication. To clarify, if we were to replicate A, then C and A would have similar particles in similar states. However, we ensured that A was no longer at its original state, and that makes all the difference.
A look into protocols of Quantum Teleportation!
To start with, quantum teleportation is about sending information over, rather than physical bodies. The best possible way to do this would be with a quantum computer, which is similar to a regular computer. There is one notable difference, which is: the former uses quantum logic gates. There are several kinds of gates defined, some of them needing only one operand, others more.
A common series of steps taken in sending a qubit across would be like this:
- First, we generate the basis vector for 2 qubits, or the vector representing their measured state.
- Next, one qubit each is sent to sender and receiver.
- The sender entangles the basis qubit with the one they want to send and measures both the qubits they have.
- They send the measured result to the receiver over a classical communication channel. This is to introduce a time delay, so that transmission does not happen instantaneously.
- Depending on the received result, the receiver applies various gates to obtain the actual message.
And that is how we transfer data quantum style. We might not ever be able to perform actual Human teleportation, but that doesn’t stop us from exploring it in other aspects. With the inception of quantum computers, we surely have taken one step closer to be a more advanced species.
What if?
“When the personality of a human is involved, exact predictions are hazardous.” Dr McCoy
Let’s just for argument’s sake say that human teleportation is possible, which will require us to scan every single bit of data of a specific human. According to studies, this is equal to 2.6*10⁴² (if you want to know how big that number is, there are only 1 billion trillion stars in the whole universe).
Now to run a machine capable of scanning and performing such teleportation, it will require the whole power supply of the UK to run for more than a million years! And even then it will take 4.8 million million years to transfer all that data (you know, the universe has only existed for like 13 billion years xD). So, it’s better to hitch a ride on the next car you see if you want to get somewhere.
Even if we do all that and wait that long, for the sake of science, wouldn’t we just be transmitting a copy of you? What would happen to the real you? Sounds scary? What if we take the risk and make two of you, would that mess the universe up? Are you ready to take that risk?
Do follow Nakshatra to join us in our exploration of the cosmos. Looking Beyond The Stars!
The article was written by ATOTMYR (Sahil) and unexpected-patronus!
