What Happens if You Cut a Photon in Half? The Answer Is Trippy

Physicists tend to think of light in terms of photons: massless, elementary particles “carrying” the forces of nature. And elementary particles, like the photon, are indivisible. That is, there is no such thing as half a photon. Or is there? That was the question that three theoretical physicists tried to answer in a recent paper published in Physical Review Letters, bluntly titled “Truncated Photon.” To be clear, the team understands that elementary particles like photons can’t be cut into two. But consider this quantum shortcut: photons exhibit the behaviors of both waves and particles. As it turns out, there is a way to split a photon using this property—although, in typical quantum weirdness, the product of this isn’t anything you’d expect. “Despite being a simple question, it appears