By Abigail Shields, Year 12
Only last week, on November 29th, researchers at the University of Stuttgart announced a breakthrough in quantum communication. This is an ongoing discipline shaping what may become the world’s most secure networks by relying on the laws of quantum physics instead of the everyday electronics used in phones, computers, and so on. Traditional communication systems, such as those used in internet networks, transmit information by copying and boosting electronic signals; however, this can not function for quantum information since quantum states cannot be copied or amplified without being destroyed.
Instead of using bits, quantum communication uses individual particles of light called photons to carry qubits. These are what carry the encoded information, and unlike classical bits that can only be 0 or 1, a qubit can exist in a superposition of both at the same time.
The data is encoded in a photon’s polarisation, which refers to the direction its light wave is oriented. Due to the fact that observation alters a quantum state, any attempt to measure or intercept the message disrupts the signal and can be detected. This unique property forms the foundation of quantum cryptography, a method focused on developing ultra-secure networks based on the laws of quantum physics rather than encrypting data alone.
Distance remains one of quantum communication’s most persistent difficulties. Presently it is complicated to send information over long distances, since light travels through optical fiber, which are thin strands of glass or plastic used for high-speed data transmission over long distances, the individual photons are gradually absorbed, causing the signal to weaken over time. Subsequent to this issue, scientists are developing quantum repeaters, devices that use a process called quantum teleportation to pass information onto new photons (one photon to another) without directly transmitting the original quantum state, allowing quantum data to be relayed step by step across much greater distances.
So these researchers recently reached an important milestone by performing quantum teleportation between photons produced by two separate quantum dots, which are tiny semiconductor structures designed to emit single, carefully controlled photons. This marks the first successful teleportation experiment using photons from independent sources. “Independant sources” means the photons were made in separate devices instead of coming from the same light source, showing that teleportation can work between distant and unconnected systems. Usually, teleportation requires photons to be almost perfectly alike in properties such as wavelength and emission timing, but photons from different devices rarely match naturally. The research team solved this problem by creating almost identical quantum dots in partnership with the Leibniz Institute for Solid State and Materials Research in Dresden and using quantum frequency converters developed at Saarland University to fine-tune the photons so they aligned precisely.
In the experiment, one quantum dot generated a photon carrying polarization information, while another produced a pair of entangled photons. One of the entangled photons was brought into interaction with the original photon, allowing the quantum state to transfer to the remaining entangled photon. In this way, the information was efficiently teleported across approximately 10 meters of optical fiber. The process achieved a success rate of over 70%, showing consistent and reliable information transfer between distinct photon sources.
This achievement reveals several researchers advances towards the creation of efficient quantum repeaters that could support long-distance communication networks. The ongoing research is focused on increasing the accuracy, and extending communication distances, though they may very slowly be approaching the realization of a secure quantum internet.
Works Cited
“Scientists Just Teleported Information Using Light.” ScienceDaily, 2025, www.sciencedaily.com/releases/2025/11/251129044516.htm.
“Understand the Concept of Teleportation and How Quantum Mechanics Makes Photon Teleportation Possible.” Encyclopedia Britannica, 2025, www.britannica.com/video/quantum-mechanics-photon-teleportation/-219075
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