Faster and more secure communication is the goal of much research in quantum mechanics. The creation of quantum networks, i.e. sets of distant nodes connected through quantum correlations, will be the turning point towards the creation of a new type of global connectivity: the quantum Internet.

Information will be transmitted using quantum teleportation, which allows quantum states to be transferred between remote locations without the need for direct transmission, exploiting quantum entanglement, i.e. a property of remote correlation that is only possible in quantum systems, such as individual photons.

The study, published in the journal Nature Communications, is the result of collaboration between two groups from Sapienza University's Department of Physics, Nanophotonics and Quantum Lab, led by Rinaldo Trotta and Fabio Sciarrino respectively. It shows how to implement a quantum teleportation protocol across the Sapienza campus, connecting three nodes established in three different laboratories and interfacing photon emitters, known as Quantum Dots. These are among the most efficient emitters of optical signals in the field of quantum communication.

The innovative aspect of the experiment lies in the use of Quantum Dots with different initial characteristics, located in separate laboratories. Quantum teleportation generally requires identical photon sources, which are difficult to manufacture. However, this experiment demonstrated that, by actively 'tuning' the frequencies of two different sources using magnetic fields and mechanical deformation, they can communicate efficiently enough to be used for quantum teleportation.

‘A first photon, onto which the state to be teleported was “loaded”, travelled from one laboratory to another through an optical fibre, until it interfered with a second photon emitted by a different quantum dot,’ says Alessandro Laneve, one of the authors of the study. ‘The interference activated the quantum teleportation of the state of the first photon to a third photon linked to the second by quantum entanglement. The third photon thus travelled through an air channel from the Marconi Building of the Department of Physics at Sapienza University to the Fermi Building, where it was analysed.’

The transfer of information therefore took place from one photon to another, without the two particles ever interacting. The accuracy achieved was 82%, well above the limit obtainable with classical communication. Furthermore, this result was achieved not only in a laboratory environment, but also in a realistic application scenario such as a hybrid network (fibre and air) connecting two buildings on Sapienza’s Main Campus.

The ultimate goal of research into quantum teleportation is to lay the foundations for the creation of a truly useful quantum Internet. To do this, reliable quantum light sources with high photon production are needed, and quantum dots are very promising in this regard, despite still having several irregularities in their manufacture.

In this regard, it has been understood that the diversity of quantum light sources is not an insurmountable obstacle to their use in quantum networks, and that the use of Quantum Dots in quantum network nodes is not only possible but already represents a very mature solution for the quantum communication of tomorrow.

References: Quantum teleportation with dissimilar quantum dots over a hybrid quantum network - Alessandro Laneve, Giuseppe Ronco, Mattia Beccaceci, Paolo Barigelli, Francesco Salusti, Nicolas Claro-Rodriguez, Giorgio De Pascalis, Alessia Suprano, Leone Chiaudano, Eva Schöll, Lukas Hanschke, Tobias M. Krieger, Quirin Buchinger, Saimon F. Covre da Silva, Julia Neuwirth, Sandra Stroj, Sven Höfling, Tobias Huber-Loyola, Mario A. Usuga Castaneda, Gonzalo Carvacho, Nicolò Spagnolo, Michele B. Rota, Francesco Basso Basset, Armando Rastelli, Fabio Sciarrino, Klaus D. Jöns & Rinaldo Trotta, Nature Communications volume 16, Article number: 10028 (2025) – DOI: https://doi.org/10.1038/s41467-025-65911-9

Further Information

Alessandro Laneve - Department of Physics, Sapienza University of Rome

alessandro.laneve@uniroma1.it