Yue Yu

Infrared light is an invisible helper: it senses heat, identifies molecules, and transmits data through the air. But controlling it is tricky: you need to switch the beam on and off quickly and change its hue, and ordinary switches are too slow or bulky. The new device solves this.

In a piece of ordinary magnet, all electron spins, tiny magnetic arrows, point in the same direction. It's a formation of soldiers facing their commander. This order is called a collinear altermagnet.

At the center of every atom lies a nucleus — a dense ball of protons and neutrons. These particles don't just crowd together randomly; they fill strict energy levels, much like floors in a skyscraper. When a floor is completely filled, the nucleus becomes especially stable — physicists call this a magic number.