Quantum Hub Thuringia: TU-Researchers develop the Internet of the future

Quanta are the smallest light and energy components. What can be understood by quantum technologies?

Prof. Jens Müller: The principle of quantum technology is based on the smallest change in a physical quantity. This technology offers the possibility of transporting information with very little energy or uses these smallest changes of state to build very sensitive sensors, for example.

What advantages do quantum technologies have over conventional systems?

Prof. Hannes Töpfer: A sensor takes a physical quantity and converts it into an electrical signal. We know this from electronic clinical thermometers, for example. These scales are coarse and suitable for home use. If we want to go to more advanced technology, such as that used in medical technology, we need sensitive sensors - sensors that use quantum principles. You can suddenly get into areas that were previously inaccessible: In the organism, without opening the body, explore processes that could not be seen before and thus diagnose disease patterns that cannot be seen with an ECG or other imaging methods, for example.

Another example: At the Leibniz IPHT in Jena, radiation sensors have been developed that work on a quantum basis. These can be used for controls in airports. Prototypically, it has been possible to show that it is possible to detect whether artificial objects are under clothing without irradiating the body. This effect goes back to Max Planck, who studied blackbody radiation. Geoexploration is another application area for quantum-based technical diagnostics. Our project partners are working on systems to explore mineral resources from the air. These examples show that quantum technologies are not science fiction, but already work prototypically today. We are working to ensure that the technologies can be applied outside the laboratory and become part of everyday life.

That means quantum technologies make devices more precise and more powerful?

Prof. Jens Müller: It is not a continuation of a technical state or the further development of conventional processes. A new quality is being achieved here. For example, one can now perform analyses in wavelength ranges that could not be done before: Things are made visible with the help of imaging; in medicine, cell examinations can be carried out that can be done better in this wavelength range.

Prof. Hannes Töpfer: It's a bit like the mission of the Starship Enterprise: You can go where no one has gone before. We penetrate areas where you can't get to with normal technologies. It's like being able to look behind a curtain.

With your research work, you are contributing to the development of the so-called quantum Internet. What does that mean and why is it being developed?

Prof. Hannes Töpfer: We all use computers and know that communication is not secure in principle. Bank transfers are a good example of how sensitive data can be. Quantum Internet comes into play to make these much more secure: Here, you use the property that you transmit data with small amounts of energy. If someone hacks into this system, this immediately interrupts the connection. For many years, there have been visions of communicating sensitive data in this way, because it has been proven that this system is tap-proof. For many fields, for example medicine or business, such security threats are relevant enough to use the quantum internet. Now engineers from the TU Ilmenau, among others, are called upon to put this technology to use.

Why is this quantum Internet currently primarily an engineering task?

Prof. Jens Müller: The basic principle of quantum communication has already been clarified. Point-to-point transmission over short distances already works. However, if we go to longer distances, another factor comes into play: Attenuation takes place during signal transmission. We are working with very small amounts of energy, and these are lost in the noise. We need a mechanism to refresh the encryption information so that it can be transmitted over a correspondingly long distance. This project must be supported by hardware technology. At the TU Ilmenau, we want to build microsystems that can be used, for example, in a communications satellite. This will ensure secure data transmission.

Prof. Hannes Töpfer: You first have to detect these light particles, or more precisely: photons, which are transmitted. You need a receiver for that. This has been solved in physics, and we are working on amplifying these received signals so that they reach a reasonable level so that they can be transported further. In the lab, we are designing such amplifier circuits with quantum devices that can detect and amplify these particles. With our basic research, we can achieve significant breakthroughs.

Why is TU Ilmenau's know-how so relevant in this field?

Prof. Hannes Töpfer: We are very far ahead in the global competition with our findings and have a lot of experience that we bring to the Quantum Hub. TU Ilmenau scientists have been working on the implementation of physical principles of action, specifically on quantum circuits in electronic components, since as early as 1969 - at that time with the aim of building energy-efficient microelectronics, and later on developing highly efficient quantum sensor technology. Since 1989, we have contributed in a way that our trace has been left in almost all leading groups in Europe. We have launched authoritative computational foundations that have been used in all major laboratories. Quantum electronics with superconductors, which we co-developed, has become established throughout Europe. For 20 years, we have also held an internationally attended training workshop every two years to prepare people for this technology. We are well networked: I am on the board of a pan-European technology association working on these quantum devices. We have been fit in the field for years and are an internationally recognized partner.

Quantum technology also offers promising prospects in energy supply with renewable energies ...

Prof. Hannes Töpfer: Quantum computing is used in this context. Quantum objects are used to implement mathematical models that open up a completely different number space than we are familiar with from mathematics in school or university. The so-called entanglement, the fact that quantum particles are related to each other, makes the data space figuratively explode. Many tasks that are difficult to master in everyday life can be solved with the help of quantum computing. Energy distribution is one of them. Feed-in points from wind farms or solar parks lead to a distribution problem that cannot be solved effectively mathematically. How to optimally provide energy where it is needed - this is an enormously challenging mathematical task that can be mastered with the help of the special capabilities of quantum computing. A problem for humanity would then become solvable all at once that has only been satisfactorily managed up to now.

What goals have you set for yourself at the Quantum Hub Thuringia?

Prof. Hannes Töpfer: In Thuringia, we already have very good examples of how quantum technology can be commercialized. For example, the company Supracon from Jena in the field of measurement technology also takes up research findings from Thuringia and is thus able to supply the market with quantum sensors for high-precision measurement systems. The alliance of eleven partners gives a new boost to the transfer of research findings into products. Thuringia has the value chains to use the know-how for valuable solutions and products. Many companies will benefit from our research results.

Prof. Jens Müller:Thuringia is called Sensorland because many companies are active in this field. We see great potential in the application of high-precision sensors based on quantum technologies. With our research, we want to create the foundations for this and show how these can be applied and integrated into products. This is the strength of the TU Ilmenau in the hub network: system integration, i.e. the implementation of research findings. As a research location, we also want to achieve international visibility in order to acquire greater funding for our research and, building on this, to conduct even more research in this area. This, in turn, will benefit regional industry.

Prof. Hannes Töpfer: We all stand to gain only if this technology comes into use and can be operated by everyone. The first users will certainly include medical personnel, but later these products will be accessible to everyone. We as engineers have the task of ensuring this usability and longevity of these products. Once the physical effect is in place, our work really starts.

When might quantum technologies find their way into our everyday lives?

Prof. Jens Müller: Things are already on the way, but so far they are only working selectively. If enough money were invested in research, this could happen very quickly.

Prof. Hannes Töpfer: I share this opinion. It can definitely happen quickly. Many companies have used the time in the Corona pandemic to convert their algorithms to quantum aspects. Users are already preparing, and that is a very positive sign that we have not felt for a long time in the field of high technologies. In addition, there is the pressure of international competition. Many companies are investing large sums in this technology. Since the value chain between research findings and implementation of these in companies already functions very well in Thuringia, I am positive about the future.

The interview was conducted by Eleonora Hamburg