The backbone of current telecommunications is a network of optical fibres that transmit information, encoded as pulses of light, around the globe. In the future, the same infrastructure might be used to transmit quantum information, which would enable unbreakable encryption and realize the full potential of quantum computers and quantum sensors. In quantum mechanics, two objects can be entangled, which means that they can no longer be described as separate objects: a description of one must involve the other. The power of quantum networks hinges on establishing entanglement between distant network nodes quickly and reliably. Writing in Nature, Liu et al.1 report entanglement between two trapped ions, separated by up to 101 kilometres of spooled telecommunications optical fibre.
Competing Interests
RH is co-founder and shareholder of Delft Networks B.V, which is developing quantum-network technology.