Jun. 3, 2021 , 12:43 PM A beam of ethereal blue laser light enters a specialized crystal. There it turns red, a sign that each photon has split into a pair with lower energies—and a mysterious connection. The particles are now quantum mechanically “entangled,” linked like identical twins who know each other’s thoughts despite living in distant cities. The photons zip through a tangle of fibers, then ever so gently deposit the information they encode into waiting clouds of atoms. The transmogrifications are “a little bit like magic,” exults Eden Figueroa, a physicist at Stony Brook University. He and colleagues have concocted the setup on a few laboratory benches cluttered with lenses and mirrors. But they have a much bigger canvas in mind.