Quantum Teleportation. © University of Science and Technology of China
Scientists at the University of Stuttgart have successfully teleported quantum information between photons coming from two separate light sources — a major step forward in developing quantum repeaters.
Quantum cryptography could make communications far more secure by using the rules of quantum physics to prevent eavesdropping. But building a full quantum internet is still technically difficult. One of the biggest challenges is creating an effective “quantum repeater,” a device needed to send quantum signals over long distances.
Physicists from the University of Stuttgart, Saarbrücken, and Dresden. From left to right: Tobias Bauer, Marlon Schäfer, Caspar Hopfmann, Stefan Kazmaier, Tim Strobel, and Simone Luca Portalupi. Credit Julian Maisch
The research team at Stuttgart’s Institute of Semiconductor Optics and Functional Interfaces (IHFG) has now achieved a key breakthrough. They demonstrated quantum teleportation using only photons, with the help of semiconductor quantum dots — tiny structures that can create quantum light at telecom-friendly wavelengths.
In their experiment, two distant gallium arsenide (GaAs) quantum dots were used. One produced entangled photon pairs, and the other generated single photons. The single photon was encoded with specific polarization states and then combined with part of the entangled pair using a special polarization-based measurement. This measurement caused the polarization state of the single photon to be teleported onto the partner photon of the entangled pair.
This result shows an important milestone toward building practical quantum networks and long-distance quantum communication.
source Nature Communications
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