In a groundbreaking research study published in Nature Communications, an international team from Wits University and ICFO – The Institute of Photonic Sciences has achieved a major breakthrough in quantum communication. The team demonstrated the teleportation-like transport of “patterns” of light, marking the first successful approach to transporting images across a network without physically sending them. This accomplishment represents a crucial step towards realizing a quantum network for high-dimensional entangled states, which is vital for information security.
Quantum communication over long distances has thus far been accomplished with two-dimensional states, known as qubits. While this is impressive compared to classical communication, where information is transmitted as a sequence of 1s and 0s, quantum optics offers the possibility of increasing the complexity of communication by describing more intricate systems. However, in existing teleportation demonstrations, only three-dimensional states have been achieved, necessitating additional entangled photons to achieve higher dimensions.
As a significant leap forward, the research team successfully performed the first experimental demonstration of quantum transport using high-dimensional states with just two entangled photons as a quantum resource. Using a nonlinear optical detector, which eliminates the need for additional photons while maintaining compatibility with any “pattern” that needs to be sent, the team achieved a state-of-the-art of 15 dimensions. Furthermore, the scheme is scalable, making it possible to reach even higher dimensions and paving the way for quantum network connections with high information capacity.
This groundbreaking research has major implications for secure communication. Imagine a scenario where a customer needs to send sensitive information, such as a fingerprint, to a bank. In traditional quantum communication, the customer physically sends the information to the bank, which poses a risk of interception, even if the transmission is secure. However, the newly proposed quantum transport scheme turns this conventional approach on its head. Instead, the bank sends a single photon from an entangled pair to the customer, who overlaps it on a nonlinear detector with the information to be sent. As a result, the information appears at the bank as if it had been teleported, without any physical transmission between the two parties. Therefore, interception becomes futile, while the quantum link between the parties is established through the exchange of quantum entangled photons.
While this protocol shares many characteristics of teleportation, it requires a bright laser beam for the nonlinear detector to efficiently determine what needs to be sent. Therefore, it is not strictly teleportation in its current form, but it holds the potential for future advancements if the efficiency of the nonlinear detector can be improved. Nevertheless, this research introduces nonlinear quantum optics as a valuable resource and opens the door to connecting quantum networks with high-dimensional secure channels.
The research team emphasizes the importance of the experiment and acknowledges Dr. Bereneice Sephton from Wits for her determination and comprehensive skill set, which played an integral role in taming the complexities of the experimental setup. Dr. Sephton is credited with getting the system to work and carrying out key experiments. Moving forward, the team plans to continue their work in this direction, with a focus on quantum transport across an optical fiber network.
The achievement of teleporting “patterns” of light in quantum communication represents a remarkable advancement for the field. The successful quantum transport of high-dimensional states using just two entangled photons breaks new ground and holds immense potential for the future of secure information transmission. As the team continues to push the boundaries of quantum communication, there is no doubt that their groundbreaking research will inspire further advancements in the field of nonlinear quantum optics and pave the way towards a fully realized quantum network.
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