With their scanning tunnelling microscope and led by Prof. Ruslan Temirov (right) as well as Dr. Taner Esat, Jülich researchers want to investigate the unusual properties of quantum materials.
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RESEARCH
The dawn of a new IT age
Researchers at Jülich are in the process of establishing computer technology on a completely new foundation. Their numerous findings pave the way to the quantum computer.
Planning flights optimally
Major airlines operate more than 1,000 flights a day to more than 100 cities worldwide. Their planning is difficult and decisive for an airline’s economic success. Personnel and machines must be used as efficiently as possible. Jülich researchers, in collaboration with partners from the European OpenSuperQ project, are already developing calculation methods for future quantum computers to create optimal flight plans with unique speed. They test these calculation methods with quantum computer simulation software, among other things.
An amazingly stable quantum system
Quantum systems are considered extremely fragile. Even the smallest interactions with the environment can cause the sensitive quantum effects to be lost. However, this does not always seem to be the case, as researchers from TU Delft, RWTH Aachen University and Forschungszentrum Jülich have discovered. In a quantum system consisting of two coupled titanium atoms, the quantum information was retained even after a sudden current surge. The result was cause for some discussion among experts. It may be that these quantum states can be created with a little less care than previously thought. The researchers now want to test whether if the result also applies to larger quantum systems.
Artistic representation of the experiment with the two coupled titanium atoms
Quantum AI for the automotive industry
Software that is capable of learning and that can do without fixed rules for every situation is already common in the automotive industry and other high-tech sectors. However, this artificial intelligence (AI) often requires a lot of computing time. The Q(AI)2 project, which is coordinated by Forschungszentrum Jülich, is exploring the extent to which quantum computers can accelerate applications in the automotive industry with AI, such as optimizing flexible production processes or steering self-driving cars through traffic without collisions. The consortium includes, among others, the car manufacturers BMW, Mercedes-Benz and Volkswagen as well as the supplier Bosch and the German Research Center for Artificial Intelligence.
Frank Wilhelm-Mauch, director at Jülich’s Peter Grünberg Institute and professor of theoretical physics at Saarland University, coordinates the Q(AI)2project
Quantum transport speed limit
Not even the special rules of the quantum world allow information to be transmitted arbitrarily fast. An international team with Jülich quantum physicist Prof. Tommaso Calarco on board has now determined the highest speed at which this can be achieved. This is significant for quantum computers in which atoms serve as qubits and thus as carriers of information. In order to perform calculations, these atoms must be shifted in the processors of such a quantum computer.
This must happen as swiftly as possible, since the qubits lose their quantum state after a certain amount of time, thus losing the information they contain. With the speed limit determined, it is now clear how often an atom can be moved in this time span, that is, how many complex quantum operations a quantum computer can perform.
Tommaso Calarco is director at the Peter Grünberg Institute in Jülich and professor of theoretical physics at the University of Cologne.
“However, the existence of the speed limit does not mean that quantum computers may not compute as fast as previously thought,” Calarco emphasizes. The decisive factor is that they need far fewer operations to master a certain task than classical computers.
Read more about the quantum speed limit in the interview with Tommaso Calarco:
t1p.de/fzj-quantum-speed-limitQuantum microscope: “Made in Jülich”
Many a bizarre property of the quantum world can be observed under a scanning tunnel microscope. Jülich physicists have further developed such a device in order to gain even more precise insights. Scanning tunnel microscopes portray materials with atomic precision and are much-used instruments for exploring the nanoworld. “We have spent years developing a microscope with magnetic cooling. This distinguishes our device from all the others in much the same way as an electric car differs from a car with a combustion engine,” says Jülich physicist Prof. Ruslan Temirov. Thanks to the new cooling system, the microscope works almost vibration-free at extremely low temperatures. It is therefore far more suitable than conventional devices for exploring the unusual properties of quantum materials near absolute zero, which is -273.15 degrees Celsius (0 Kelvin). Special quantum phenomena often manifest themselves at such temperatures, which scientists need to understand precisely in order to advance quantum computing. “Our next step is to develop a commercial prototype,” says Prof. Stefan Tautz, director at Jülich’s Peter Grünberg Institute.
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Cables, tubes and many other components: even so, thanks to magnetic cooling, the Jülich quantum microscope manages without moving parts.
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The principle of magnetic cooling is not new. However, the Jülich researchers – pictured: Dr. Taner Esat (left) and Danyang Liu – are the first to have constructed a scanning tunnelling microscope using this technique.
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The new cooling technology not only improves the quality of the images, but also simplifies the operation of the device for the team led by Prof. Stefan Tautz, Dr. Taner Esat and Prof. Ruslan Temirov (left to right).
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With its modular design, the Jülich quantum microscope is open to technical advances, and researchers – pictured here is Danyang Liu – can easily incorporate upgrades.
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Using a computer, the researchers can examine and evaluate the images produced by the quantum microscope – pictured: Danyang Liu, Prof. Stefan Tautz, Dr. Taner Esat and Prof. Ruslan Temirov (left to right).
Cooperation on exotic qubit candidates
There are several ways to realize qubits for quantum computers: for example, superconducting circuits, ion traps or semiconductor quantum dots. Candidates also include topological insulators in a superconducting Josephson bridge. Topological insulators are a special class of materials: their interior acts as an insulator while the surfaces conduct current almost without loss, since the angular momentum and the direction of movement of the electrons are coupled there. If this material is incorporated into a so-called superconducting Josephson bridge – in which an insulator lies between two superconductors, itself acting as a superconductor under certain conditions – exotic, very stable quantum states are created. Such components could help slash disturbances that arise during computing operations with current technology and lead to errors in the calculations. Julius-Maximilians-Universität of Würzburg and Forschungszentrum Jülich have been working closely together for several years on research into topological material systems. In the future, the Free State of Bavaria will fund the cooperation with €13 million for the development of quantum computing applications.
Texts: Frank Frick
Processing of Josephson Junctions and Qubits in the Helmholtz Nano-Facility (HNF)
Quantum computer for Europe
In the OpenSuperQ project, the first freely programmable European quantum computer is being built at Jülich. 10 partners from research and industry are developing and building the new computer. But how does the computing of the future actually work? One video provides insights into the technologies and process. More about Jülich quantum research online at go.fzj.de/quantum-EN
and in the cover story of effzett 1-21 “Quantum cosmos adventure”.Photos: Forschungszentrum Jülich/Sascha Kreklau, Enrique Sahagún, Scixel Video: Eurice