In This Image, Two Photons Interact. Here's Why It's Groundbreaking.

Normally, photons want nothing to do with one another. Light waves just pass through each other like ghosts. But now, for the first time ever, scientists at the University of Vienna have coaxed a strong interaction between two single photons. It's an achievement that opens up radical new possibilities for a number of… »11/04/14 3:30pm11/04/14 3:30pm