Quantum Photons Survive a 24-Kilometer Journey Through Chicago's Busy Internet

Researchers at Northwestern University demonstrated the first real-world distribution of entangled photons through 24.4 kilometers of installed fiber-optic cable while the same cable carried high-capacity telecommunications traffic, with the quantum connection retaining more than 94% fidelity. The result was published in Optica Quantum.

This is an early-stage demonstration; practical quantum networks would require further development and deployment.