What is the quantum internet, and why would we need one?

The answer

The quantum internet would use quantum entanglement and quantum key distribution (QKD) to enable theoretically unhackable communication. When entangled particles are measured, any eavesdropping attempt disturbs the quantum state, immediately alerting both parties. China leads development: its Micius satellite (launched 2016) demonstrated satellite-to-ground QKD over 1,200 kilometers, and the Beijing-Shanghai quantum backbone network spans 2,000 kilometers using trusted relay nodes. In 2024, a team at Delft University of Technology demonstrated quantum teleportation across three nodes - a key milestone for multi-node quantum networks. The US Department of Energy published a quantum internet blueprint in 2020, establishing a Chicago-based testbed. Toshiba achieved QKD over 600 kilometers of standard fiber optic cable. Applications beyond secure communication include distributed quantum computing (linking multiple quantum computers), ultra-precise GPS, and synchronized telescopes for enhanced astronomical observation.