Technologies For More Powerful Quantum Computers

The planned improvements concern both increasing the number of connections between the individual qubits and improving the qubits’ quality and thus the possibility of quickly and efficiently producing the desired quantum states. Quantum computers should be able to solve previously unsolvable problems efficiently.

For example, this includes calculating the properties of complex molecules for the pharmaceutical industry or the optimization tasks’ solution, be it for manufacturing processes in the automotive sector or analyses from the financial world. In the joint project “GeQCoS,” Germany’s leading researchers in the field of superconducting quantum circuits have developed with the participation of the Karlsruhe Institute of Technology (KIT)more innovative Targeted concepts for the construction of an improved quantum processor.

The quantum processor prototype developed in the joint project “German Quantum Computer based on Superconducting Qubits,” GeQCoS for short, consists of a few superconducting qubits with fundamentally improved components. With this technology, the essential building blocks of a quantum computer, the quantum bits – qubits for short – are implemented using currents flowing without resistance in superconducting circuits. These currents are relatively robust against external interference and can retain their quantum properties over long periods.

The planned improvements concern both the increase in connectivity, i.e., the number of connections between the individual qubits, and the improvement of the qubits’ quality and thus the possibility of being able to produce the desired quantum states quickly and efficiently. “It’s a big challenge at this stage,” says Dr. Ioan Pop from the Institute for Quantum Materials and Technologies at KIT. “By using new types of materials for manufacturing the qubits, we expect better reproducibility and higher quality of the qubits.”

To achieve an improvement in this area, the researchers are working on alternative components, changes in architecture, coupling mechanisms, and higher accuracy of calculations. “This is a crucial step towards the development of superconducting quantum circuits in Germany. This technology is preferred by IT executives in the field of quantum computers. It is currently being pursued”, emphasizes Professor Alexey Ustinov, head of the research group at the Physics Institute of KIT. “This is a demanding research activity to localize and diagnose errors. We have to improve the manufacturing methods to avoid imperfections that have a lasting effect on the qubits’ quality.”

According to the experts, quantum computers can master small, specific problems and show how they work. The long-term goal is to develop a so-called universal quantum computer that can calculate significant arithmetic problems exponentially faster than a conventional computer. A suitable architecture for calculating practical problems can only be realized through actual hardware and software improvements.

To achieve this goal, scalable manufacturing processes are also being developed in the joint project, and the development of optimized chip housings is advanced.

The quantum processor is to be demonstrated on a prototype at the Walther Meißner Institute of the Bavarian Academy of Sciences. The technologies developed should lead to new scientific knowledge and strengthen the quantum ecosystem in Germany and Europe through close links with companies. The developed quantum processor should be made available to innovative first-time users as early as possible on both the hardware and software levels.