Quantum computing, which Reuters calls “one of the holy grails of science,” is closer than ever after a new invention that can produce “entangled” light on demand. In theory, quantum computers could try out multiple solutions to one problem at once, enabling them to solve problems that might take our computers years to solve, in a matter of seconds. Quantum physics looks at the universe at the level of atoms and other tiny particles, but harnessing its powers remains a challenge. However, a new simple-to-make device, created by scientists at Toshiba and the University of Cambridge’s Cavendish Laboratory, can be hooked up to a battery and make entangled light. “It means you can now start to integrate lots of devices on a single chip,” said Andrew Shields of Toshiba. Quantum computers, based on optical processes, need lots of entangled photons, where light particles are linked to exist in two possible states at once. Until now, this was only possible with lasers, but this new technology is a big step forward in the optical approach.