Quantum Internet is getting closer. Quantum memories were connected over a record distance

According to many researchers, we are already one step closer to a quantum Internet, although so far few of us had any idea of its existence. Is this really a breakthrough in the use of the web?

A group of scientists in China connected quantum memories that were 50 kilometers apart, meaning they managed to break the previous record by more than 40 times! According to the researchers, this is a huge step towards a new Internet, because although the one currently available is truly revolutionary, connecting the whole world to each other, it has its problems, such as the presence of hackers. It is their activities that have prompted the researchers to try to create a completely new internet, resistant to hacking attacks.

This is where a network governed by the world of quantum mechanics comes into play, which could one day become the standard for sending, receiving and storing data securely. How. In the classical computer world, information is represented by bits of either 0 or 1, while a quantum Internet, like a quantum computer, would take advantage of one of the key properties of quantum mechanics, the principle of superposition, most often illustrated by the well-known paradox of the so-called Schrödinger’s cat.

When translated into a quantum description, we have this situation – before opening the container, the cat is both dead and alive. As a quantum object, it is simultaneously in each of the possible states (the so-called superposition) and only opening the container and checking its contents reduces the system to one state, the cat is either dead or alive. And so quantum computers use qubits which can exist in any superposition of two quantum states, i.e. taking the value 1 and 0 at the same time. Only making appropriate measurements by the user forces them to take the final state which is 0 or 1.

And if we connect two or more qubits together, these create the so-called entangled state, with the feature impossible in classical physics, consisting in the fact that the state of the whole system is better determined than the state of its parts. This ethereal connection means that any action performed by one qubit is immediately also performed by the others, regardless of the distance. This is what the quantum internet is based on, sending data through these connections, otherwise known as quantum teleportation. And since the entangled qubits are not physically connected to each other, intercepting the communication between them is impossible, hence the assurances of a secure internet.

And there is only one “but”, because although in empty space this process is not difficult and scientists have managed to connect light particles 746 km away in such a way, in real conditions entanglement is very demanding and even the smallest disturbances, such as changes in temperature or vibration, can break the entanglement. So researchers have to use so-called quantum memories, devices that store quantum information about the superposition of two states, and they are getting better at it. In fact, Wei Pan, a professor at the University of Science and Technology of China, and his colleagues broke the previous record and connected quantum memories 50 km away – the previous result was only 1.3 km. However, as we mentioned, the entangled state is just the beginning and now the researchers are preparing for quantum data teleportation, which may indeed be the beginning of a new Internet.

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