← Quantum Computing Fundamentals
Day 11 of 14
Quantum Networking & The Quantum Internet
Quantum Networks
A quantum internet would connect quantum computers using quantum communication channels, enabling:
BLIND QUANTUM COMPUTING: Send a computation to a quantum server without the server knowing what it computed. The computation is encrypted in the quantum state itself.
DISTRIBUTED QUANTUM COMPUTING: Link multiple smaller quantum computers together to simulate a larger one. Crucial for scaling beyond single-chip limits.
QUANTUM SENSING: Networks of quantum sensors for navigation, timing, and gravitational measurements — more precise than any classical sensor.
QKD NETWORKS: Already deployed. China has the world's largest — a 2,000km quantum-secured communication link between Beijing and Shanghai using a combination of fibre and satellite.
Quantum Repeaters — The Technical Hurdle
Classical networks amplify signals to send them long distances. Quantum signals can't be amplified without destroying the quantum information (no-cloning theorem).
SOLUTION: Quantum repeaters use entanglement swapping — create entanglement between adjacent nodes, then 'swap' it to extend the range without measuring the quantum state.
CURRENT STATUS: Short-distance quantum links (tens of km) are operational. The Netherlands has a 4-node quantum network. Long-distance repeaters (hundreds of km) remain experimental. Satellite QKD (China's Micius satellite) bypasses the repeater problem for ground-to-satellite links.
TIMELINE: Small-scale quantum networks operational now. Large-scale quantum internet: 2030-2040.
⚡ Today's Action
Look up the QuTech quantum network in Delft, Netherlands — it's the world's most advanced research quantum network. Their blog has excellent accessible explanations of quantum networking.
💡 Pro Tip
The quantum internet won't replace the classical internet — it will complement it. Most traffic will still be classical. Quantum channels will carry sensitive key exchange and specific high-security applications.