German scientists have made a significant breakthrough in the field of quantum information technology by successfully implementing the first interstate quantum key distribution (QKD) experiment using quantum dots as a source of single photons. This experiment marks a major advancement in the development of more secure and robust quantum internet networks in the future.
Current traditional encryption methods primarily rely on complex mathematical algorithms. However, with the rapid advancement of quantum computers, these methods are gradually becoming insecure. This has prompted the need to develop new security methods, among which quantum key distribution (QKD) stands out as a promising solution. QKD leverages the unique properties of quantum physics to ensure information security during data transmission, thereby protecting information from dangerous cyber attacks.
Unlike the current internet based on bits of information that can be either 0 or 1, quantum internet uses quantum particles (qubits) that can exist in multiple states simultaneously. This allows for much faster and more secure information transmission compared to current technology.
Breakthrough from the Interstate Quantum Dot Experiment
In a recent study published in the journal Light: Science and Applications, a team of German scientists led by Professor Fei Ding from Leibniz University Hannover, Professor Stefan Kück from the Federal Institute of Physics and Technology (PTB) in Germany, and Professor Peter Michler from the University of Stuttgart, conducted the first quantum key distribution experiment using a single photon source from quantum dots. This experiment not only opens up the possibility of applying quantum dots in the field of quantum communication but also demonstrates the feasibility of implementing this technology in actual communication networks.
Quantum dots, referred to as “artificial atoms” in the quantum world, show immense potential in developing quantum light sources and are used to emit single photons – a crucial element in quantum key distribution. The research team utilized semiconductor quantum dots to create a single photon source, paving the way for building secure and reliable quantum internet networks.
Thanks to the phenomenon of quantum entanglement, information can be transmitted instantaneously, regardless of distance.
Quantum Link in Lower Saxony
The experiment was conducted as part of the “Lower Saxony Quantum Link” project, connecting the two cities of Hanover and Braunschweig through a 79 km optical fiber. In this experiment, Alice, the device located at Leibniz University Hannover, prepared single photons to encode information by adjusting their polarization. Bob, the device at the Federal Institute of Physics and Technology (PTB) in Braunschweig, played the role of decoding these single photons as they were transmitted through the fiber.
This is the first time a quantum communication link has been successfully implemented between two cities in real life. The experiment demonstrated that using quantum dots can be highly effective in transmitting quantum keys over long distances.
Information is encoded using the laws of quantum physics, and any attempt to intercept or copy the information will alter the state of the qubit, making the attacker easily detectable.
Achievements and Development Potential
The research team achieved impressive results with stable and rapid quantum key transmission. In the laboratory, the positive key rate (SKR) reached distances of up to 144 km with a signal loss of 28.11 dB. In practice, key transmission with a low quantum bit error rate lasted for 35 hours, demonstrating the potential of this technology in real-world environments.
This result surpasses existing quantum key distribution systems and brings us closer to the performance of advanced QKD protocols based on weak coherent pulses. This highlights the great potential of quantum dots in developing high-capacity and large-scale quantum communication networks.
In addition to quantum key distribution, scientists hope that quantum dots can be used in various other quantum internet applications, such as quantum repeaters and distributed quantum sensors. This is due to their ability to store quantum information and emit clustered photon states from quantum dots.
The quantum internet will facilitate the development of quantum computers capable of solving complex problems that current computers cannot handle.
Towards a Quantum Internet Future
Secure communication has always been an essential human need, and quantum communication technology may provide the answer to this issue. By utilizing the unique properties of light, this technology ensures that information cannot be intercepted or tampered with. The success of the experiment has opened a new future for quantum internet applications, where information is absolutely secure.
Professor Fei Ding, one of the lead researchers, expressed his excitement, stating: “A few years ago, we could only dream of using quantum dots in practical quantum communication scenarios. Today, we have demonstrated their potential for exciting experiments and applications in the future, aiming for a safer and more efficient quantum internet.”
With this breakthrough, quantum technology continues to advance towards the future, opening up great opportunities for the development of a more secure and robust global communication network.
