Researchers at the University of Stuttgart have reported a breakthrough that brings the quantum internet concept closer to reality: they successfully teleported quantum information between photons emitted from different quantum dots – in other words, from physically distinct nanoscale light sources.
This kind of teleportation is exactly what quantum repeaters need to extend entanglement over long distances. The main challenge is that photons coming from different sources are usually distinguishable, which ruins the delicate interference needed for teleportation. The Stuttgart team solved this by using “quantum frequency converters” to iron out the residual differences, effectively making photons from separate devices behave as if they were twins.
The work, reported in Nature Communications, builds on Germany’s Quantenrepeater.Link and QR.X initiatives and shows that solid-state emitters like semiconductor quantum dots can be networked in a realistic repeater architecture. That’s important because future quantum networks won’t rely on a single monolithic device: they will need many heterogeneous nodes stitched together, each contributing photons to a shared entangled backbone.
In practical terms, this milestone suggests that long-distance, multi-hop quantum links – capable of supporting quantum key distribution and other entanglement-based protocols across cities or even countries – are becoming more than just theory. The next steps will involve scaling up the distance, improving stability outside the lab and integrating these repeaters with existing fiber infrastructure.
