Imagine that something is happening before your eyes, but you can’t see it — not because you have eye trouble or because it’s a microscopic event, but because of something like Harry Potter’s invisibility cloak. Two years ago, researchers from Cornell University made that fantasy come true, on a tiny scale. They not only hid the existence of a brief event — the movement of a light ray from one point to another — but also the fact that it had been hidden. One of the lead researchers on that study, Moti Friedman, is now setting up his own physics...
