European team teleports a photon’s quantum state over 270 meters, paving the way for scalable quantum relays and a future quantum internet.
A European research consortium has reported the first successful quantum teleportation of a photon’s polarization state between two different quantum dots, a milestone that strengthens the roadmap toward a practical quantum internet. The experiment, led by Paderborn University in collaboration with partners in Italy, Austria and Germany, demonstrates that semiconductor quantum dots can act as deterministic sources for long-distance quantum communication.
Instead of physically sending a fragile photon from one node to another, the team teleported its polarization state — the quantum information it carries — from a photon emitted by one quantum dot to a photon from another, spatially separated quantum dot. To test this in realistic conditions, the researchers used a 270-meter free-space optical link between buildings and achieved a teleportation fidelity of about 82%, significantly above the classical limit and more than ten standard deviations beyond what any non-quantum protocol could reach.
The work builds on more than a decade of coordinated effort in materials science, nanofabrication, and optical quantum engineering. Quantum dots were grown with nanometer precision at Johannes Kepler University Linz, resonator structures were fabricated at the University of WĂĽrzburg, and the teleportation experiments were carried out at Sapienza University of Rome. GPS-synchronized clocks, ultra-fast single-photon detectors, and active stabilization were needed to keep the link aligned and compensate for atmospheric turbulence, underscoring the engineering complexity behind real-world quantum networking.
Crucially, this teleportation used two distinct emitters rather than a single quantum source. That distinction matters: future quantum repeaters and relays will require many independent nodes that can exchange entanglement and teleport information between them. Until now, demonstrations mostly involved photons from the same device. Showing that independent quantum dots can be linked in this way moves the field closer to scalable architectures for long-distance, secure communication.
Conclusions:
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This is the first verified quantum teleportation between photons emitted by two separate quantum dots, not just a single source.
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The experiment achieved 82% teleportation fidelity over a 270 m free-space link, comfortably beating the classical limit.
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The result strengthens the case for semiconductor quantum dots as scalable building blocks for quantum relays and future quantum-internet infrastructure.
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Next steps include entanglement swapping between quantum dots to realize full quantum repeaters based on deterministic photon sources
