In a lab in Cambridge, Mass., a vacuum chamber the size of a shoebox has made history. Here, Harvard physicist Ofer Firstenberg has created a new form of matter: a pair of photons, stuck together. The “light molecule” is, potentially, the building block of technology that uses some form of tangible light — from light sculptures to lightsabers to (perhaps more practically) computers that can perform vastly more complex calculations than today’s machines.
Unlike atoms and the matter they’re made of, two photons on a collision course will simply pass through one another, with no interaction. To get photons to stick together, a first step for all the above technologies, Firstenberg and his team used a setup they’ve spent years perfecting. They rigged a specialized metal box with a laser on one side to let in one photon at a time. The first photon slips into a cloud of rubidium ...
