Italian scientists ‘freeze’ light, unlocking a new quantum mystery—Here’s what it means

Italian scientists have achieved a surprising feat—freezing light. The discovery, recently published in Nature, shows that light can behave as a supersolid, a state of matter that flows without friction while maintaining a solid-like structure. Researchers Antonio Gianfate from CNR Nanotec and Davide Nigro from the University of Pavia led the study. They described the findings as "just the beginning" of understanding supersolidity in light.

A supersolid is a rare state of matter where particles are both rigid and fluid-like. Until now, it had only been observed in Bose-Einstein condensates (BEC), which form at temperatures near absolute zero. By manipulating photons under controlled quantum conditions, the scientists demonstrated that light, too, can exhibit this behaviour.

How Scientists ‘Froze’ Light in the Lab
Freezing usually involves lowering a liquid’s temperature until it becomes solid. However, the researchers took a different approach, creating a supersolid state in light using advanced quantum techniques. They worked with a semiconductor platform where photons, the fundamental particles of light, behaved similarly to electrons.

Using a gallium arsenide structure with microscopic ridges, they fired a laser to generate hybrid light-matter particles called polaritons. As the number of photons increased, they formed a pattern known as satellite condensates. These condensates had the same energy but opposite wavenumbers, leading to a distinct spatial structure—an indicator of supersolidity.