Posted on 5/30/2022 at 6:00 p.m.
Still in the realm of desires, the quantum internet will not exchange information like the classic bits, the values 0 and 1 that are the basis of computation. You need qubits, quantum bits. Scientists at the University of Delft (Netherlands) have created a basic network of sharing in this regard: the use of teleportation three times. For experts, this is a key step towards a revolutionary and secure internet. Details of the work were presented in the latest issue of the journal Nature.
Ronald Hanson, the author of the article, explained that a quantum internet will be a large-scale network that will connect users through new applications and “impossible to produce with the classic web.” It is hoped that in this sense a system will not be created in less than 10 years, but qubits are the ways to invest.
These innovative bits are incorporated into the laws of quantum physics, which govern the world on an infinite scale. One of these properties is entanglement, a phenomenon in which two entangled particles behave alike, regardless of the distance between them. It is as if they are connected by an invisible thread, sharing the same situation.
The connection between them is so perfect that scientists talk about a kind of teleportation. Thus, theoretically, a change in the properties of one immediately changes those of the other, no matter where they are. Today, quantum bits can be transmitted via fiber optics, but teleportation is limited: after 100 miles, the signal disappears or is lost. In order not to lose contact, the qubits must be connected directly by a quantum “chain”.
In an article published in the journal Nature, the Dutch team describes how to insert a relay, an electrical device that causes sudden changes in systems, to increase the connection area. With that, the quantum communication that was usually limited to two actors named Alice and Bob now has a third character, Charlie.
In the experiment, diamond-based qubits were placed in a circuit with three interconnects called quantum nodes. The Alice and Bob nodes were in two labs a few feet away and connected via fiber optics. At the same time, he was directly connected to Bob Charlie. Alice and Charlie could not communicate.
First, the researchers intertwined the physically connected nodes (the Alice-Bob pair and the Bob-Charlie pair). They then used Bob as a mediator and, through a complicated exchange, managed to reunite Alice and Charlie. Thus, although they were not physically connected, the two were able to send a message directly to each other. The signal was also of excellent quality, with no loss, a challenge in the face of the extreme instability of a quantum bit.
The transmission was made in a secure manner. With entanglement, any attempt to intercept or listen automatically changes the qubits, destroying the message itself. According to the group, the embryo network of the first quantum teleportation paves the way for large-scale connections.
On a laboratory scale, it demonstrates the principle of a reliable quantum repeater that can be placed between nodes of more than 100 kilometers, thereby increasing the strength of the signal. “The triumph of basic science and a real-world solution is the advancement of applied quantum physics,” the authors celebrate.