Scientists have achieved the first successful teleportation of a photon's quantum state between two entirely separate devices, a result that researchers say brings the prospect of a large-scale quantum internet meaningfully closer. The experiment, conducted by an international team including researchers from Paderborn University and Sapienza University of Rome, used a 270-metre open-air optical link to connect two independent quantum dot systems. The findings are published in the journal Nature Communications.
What was demonstrated
The team transferred the polarisation state of a single photon produced by one quantum dot to another quantum dot located in a different building on the same campus. A quantum dot is a tiny semiconductor structure, just a few hundred atoms in size, that can emit individual photons reliably. What makes this result significant is that previous teleportation experiments required both photons to come from the same source. That restriction made it impossible to link separate network nodes, which is a fundamental requirement for any real-world quantum communication system. The team achieved a teleportation fidelity of 82 per cent, well above the threshold needed to surpass what classical systems can do.
How the experiment worked
The protocol used three photons in total. Two were produced by one quantum dot and entangled with each other. The third came from the second quantum dot at the remote location. The entanglement between the first two photons was used to transfer the quantum state of the incoming photon across the link, without physically moving the particle itself. The system used GPS-assisted synchronisation and high-speed single-photon detectors to overcome atmospheric interference across the open-air link. Quantum dots were developed at Johannes Kepler University Linz, with nanofabrication carried out at the University of Wurzburg. The result of a decade-long collaboration, the project involved coordinated contributions from research centres across Europe.
Why it matters for future networks
The core problem in building a quantum internet is distance. Quantum signals carried by photons degrade over long distances and cannot simply be amplified the way classical signals can. Amplification would destroy the quantum information. The solution is a quantum relay, a device that can receive a quantum state, hold it briefly, and pass it on to the next node without reading or copying it. Until now, scientists lacked a reliable way to transfer quantum states between independent emitters, which is exactly what a relay requires. This experiment provides a working demonstration of that transfer. A separate European consortium, backed by nearly 12.4 million euros in federal funding, is already working to extend this technology to fibre-optic networks as part of a project running through to early 2028.
What comes next
Researchers are cautious about timelines. A functioning quantum internet, one capable of connecting cities or countries with provably secure links, remains a long-term objective. What this experiment establishes is that the building blocks are real and workable. The next steps involve extending the range beyond 270 metres, improving fidelity, and integrating these systems with quantum memory components. In February 2026, a Chinese research team demonstrated quantum entanglement maintained across 100 kilometres of optical fibre, suggesting the field is advancing on multiple fronts simultaneously. For sectors where data security is paramount, including finance, defence, and healthcare, these advances carry significant long-term implications. Progress is measured in milestones, and this one counts.
