Can you tell us about your research journey so far?
I obtained my Physics degree at the Technical University of Vienna and a second degree at Uppsala University as part of an exchange program. I then continued with a PhD in neutron physics under the supervision of Helmut Rauch at the Atominstitut of the TU Vienna. While neutrons are perfect spin half particles and well suited for studying fundamental questions in quantum information processing, they don’t interact much with one another; following my PhD, I therefore turned my attention to superconducting qubits by joining Andreas Wallraff’s group at ETH Zurich as a postdoc and, later, as senior researcher. Then I moved on to IBM, first to the T.J. Watson Research Center in Yorktown Heights, US and later moved back to Europe by joining the IBM Zurich Research lab in Switzerland. There I led the experimental team working on superconducting circuits, investigating topics such as tunable couplers and optimal control. In 2020 I moved to TUM and the Walther-Meißner Institute (WMI).
You are the Director of the WMI in Munich and the Head of its Division Quantum Computing and Information Processing. What role does this institute play in the quantum landscape of Europe and more specifically Germany?
WMI places itself at the intersection between technology and research. It has a long tradition as a research institute concentrating on low-temperature physics, cryogenics and superconductivity. With our involvement in new projects such as the Munich Quantum Valley, we have intensified our efforts on quantum computing and technologies. This consortium aims at building quantum computer demonstrators in Bavaria. This initiative is tightly connected with quantum technologies investments at the German national level: we're also part of the MUNIQC-SC project, funded by the federal Ministry of Education and Research (BMBF), aimed at making quantum computers accessible and at building quantum processors with up to 100 qubits.
The WMI has currently three directors: Rudolf Gross has headed the institute for more than 20 years with focus on quantum science, superconductivity and magnetism. In 2020 he was joined by me working on quantum technologies and very recently by Peter Rabl with his quantum theory group. With this organization, we are in an excellent position to bring together experimental and theoretical skills with the aim of understanding the science that underlies quantum technology and, in this way, enable its transfer to industry.
Can you tell us about the current research direction of your group?
We work on the control systems, software, and fabrication to scale up quantum computers and develop novel concepts. This often means that we collaborate with specialized companies and organizations such as Zurich Instruments on the control systems and software, as well as the Fraunhofer Institute and Infineon on microfabrication. The vision is that all processes come together to build a quantum computer to attain a higher level of scalability, reliability and robustness, as is required by the industry sector.
From today’s perspective, it wouldn’t make sense for our institute to build devices with, say, 10000 qubits, but we do want to contribute to that vision by developing technologies that are needed on the way to those qubit numbers, for example cryogenic controls and multiplexing techniques, as well as materials research aimed at eliminating two-level systems or quasiparticles, which are a major source of irreproducibility.
What is especially promising in this area in your view?
Aside from the vision to use multi-qubit devices for quantum computing and to study quantum physics itself, an exciting aspect is the way in which advances in fabrication technology will allow us to bring different systems together. One technological aspect is to integrate parts of the control circuit on the quantum processor chip, another one to create hybrid systems, e.g. with semiconductor components for quantum memories and quantum transducers. There are many possibilities when we explore the physical effects of these interacting quantum systems.
Another topic is how to use system-wide feedback to create larger quantum states that would open new possibilities for metrology or quantum error correction. Large entangled states are very sensitive to fluctuations, which we actually want to avoid in quantum computing, but understanding how these resources can be useful to other applications is an appealing goal.
You are a user of Zurich Instruments’ quantum computing control solutions. How did the instruments and software help your team in your experiments?
What is interesting about your system is that it provides flexibility beyond very specific quantum computing routines, but it combines this flexibility with a capability for scaling up and for synchronizing many channels. For our research roadmap, it’s important to work with a company that thinks along the same directions as we do, namely – what is needed for high-fidelity scalable devices?
I would add that the most valuable aspect lies in having people on both sides who speak the same language and want to push towards building larger quantum computers, whether through larger devices, more advanced and intuitive control capabilities, or better performance of the instruments.
Thank you for sharing your insights during this interview.
