Ian A. Walmsley

Light races through a maze of mirrors and beam splitters, but at the end of its journey, it doesn't just flash on a detector: it transforms itself. In the new photonic computer, nonlinear modules have been added to the familiar linear circuits, and now light can perform any quantum operation, not just a subset.

Light is the fastest courier, but it can't wait. For quantum computers to exchange messages, we need memory that can catch a photon and hold it until the recipient is ready. In warm metal vapor, atoms buzz around like bees in a hive, and each movement scrambles the recording. As a result, stopped light quickly turns into mush.