Chuan-Feng Li

For the quantum internet, we need to learn how to hold light — much like mail is sorted at intermediate nodes. The technology is based on a thin crystal plate doped with europium ions, a rare-earth element that, incidentally, is responsible for the red glow of smartphone screens.

Open systems exchange energy with their surroundings, like a guitar string fading into the air. Scientists built such a system out of light, twisting the beams into corkscrews and forming an artificial lattice — a maze where losses can be controlled at every step. Light in this maze always moves at the maximum possible speed, but its energy can fade or grow.

Quantum light is not just a stream of particles but an intricate pattern woven from space and time. A single photon can be stretched, squeezed, smeared across different directions.

In a silicon carbide crystal, which looks like a transparent stone, there are hidden defects — places where atoms are out of line. One such defect acts as a quantum node: an electron inside it spins and processes information, while the nucleus of a neighboring atom quietly stores it.

Two simultaneous interpreters sit in the same booth. The first translates from English into Russian but swallows half the words. The second goes from Russian into French, and also loses half. If you put them together, you'd expect a mess: the losses would add up, and only a quarter of the meaning would reach the listener. But what if they start correcting each other?