Researchers achieved the first real-world demonstration of quantum entanglement over a busy telecommunications fiber network. The quantum connection retained more than 94% fidelity, showing that delicate quantum signals can survive alongside conventional data streams in existing infrastructure. Quantum signals face overwhelming noiseToday’s internet represents information using bits with values of 0 or 1. One important resource is quantum entanglement, in which the states of two particles remain inseparably connected even when the particles are far apart. In laboratory tests, they used the method to perform quantum teleportation across a 30-kilometer cable carrying high-speed internet data.