Physics: Unite to build a quantum Internet

Almost 25 years ago, physicists discovered a way of 'teleporting' a quantum system from one place to another without moving it¹. There are physical limits to such teleportation: nothing can be transmitted faster than the speed of light; and Heisenberg's uncertainty principle restricts what we can know about the state of a quantum system at a given time. Nevertheless, the transported system is a replica that perfectly mimics the original, thanks to the weirdest feature of quantum mechanics — entanglement. Described by Albert Einstein as “spooky action at a distance”, this property enables distinct quantum systems to become intimately correlated so that an action performed on one has an effect on the other, even for systems that are too far apart to physically interact.

Quantum states are fragile and cannot be sent through conventional lines of communication; quantum teleportation offers a reliable and efficient way to transfer quantum information across a network. It provides the most promising mechanism for a future quantum internet, with secure communications and a distributed computational power that greatly exceeds that of the classical Internet.