At the LMU in Munich, researchers have for the first time succeeded in transmitting data via an entangled atom. The so-called quantum internet is thus moving a little closer.
In which direction are computers developing? Countless researchers are investigating this question. Since the invention of the modern computer, the actual concept has hardly changed. Depending on whether voltage is present, the command is interpreted as 0 (off) or 1 (on). All arithmetic operations are then based on this.
But how can this concept be further developed? The solution lies in quantum computers. To fully explain how it works would go beyond this article. What is important, however, is that in the future quantum computers will communicate via small particles such as atoms. When two particles form a connection, this is called entangled.
In Munich, the quantum internet becomes reality
At Ludwigs Maximilian University, in cooperation with Saarland University, such an entanglement over several kilometers has now been achieved for the first time. For this purpose, two optically trapped rubidium atoms were used. Two labs on campus each housed one of these atoms.
The data was then transmitted via a fiber optic cable below the Geschwister-Scholl Platz. A quantum network consists of many individual nodes, the quantum memories. Ions, crystal lattices or the atoms used here are used for this.
The nodes can receive, store and send information via light particles. Usually this is done by infrared waves, which are quickly lost in a fiber optic cable. By increasing the wavelength, the researchers solved this problem, which means that the information could flow through a fiber optic cable.
Quantum record: communication via fiber optics
During transmission, a communication similar to that of telecommunications networks was achieved. Although the efficiency still needs improvement, it has already reached record values of around 57 percent. And this is how the transmission happens: A laser beam excites atoms so that they spontaneously fall into their ground state and each emit a photon (a light pulse).
This travels through the fiber optic cable and is received and interpreted by the atom on the other side. The result is a form of communication that is currently secure from external attacks and offers a secure communication medium.
It should be clear that this has many advantages and disadvantages. Nevertheless, the approach impressively shows how complex the matter is. So far, information has traveled a distance of 33 kilometers. It will probably take a while before we get to an international broadcast.