In conversation with Kathrin König

Have you always wanted to become a scientist?

Actually, after high school, I first trained as a nurse and worked in an intensive care unit. I realized that I wanted to understand the medical equipment better that I used every day and I found the technology behind it so exciting that I decided to study something along these lines. When I looked at various study programs, I realized that I wanted to study a broader topic not only medical technology. That is how I came across microsystems engineering at the IMTEK in Freiburg, where I studied for my bachelor and master's degree.

How did you get from microsystems technology to quantum research?

I started in 2019 as a student assistant at Fraunhofer IAF and wrote my master’s thesis on the parallelization of monolithic gallium nitride half bridges for a compact 48 V high current power module - a power electronics topic. At the institute I became aware of quantum research and especially quantum computing and was immediately fascinated. The idea of building a computer from the tiniest particles inspired me.

Initially, I wanted to go out into the world after graduation, but the topics at IAF are so exciting and the colleagues were so great that I decided to stay here. In addition, I probably would not have found such a fascinating topic for my doctorate anywhere else. It combines software and hardware: the programming and control of quantum computers and nitrogen vacancy centers as qubit technology for future quantum computers.

What are you working on right now?

At the moment I am getting to know the program for controlling quantum computers from IBM and how their qubits work. For this purpose, I am working on a quantum computer via cloud access. I’m programming complex tasks and then send them for calculation to the quantum computer, which gives me the results. Currently, I am simulating the binding energies of lithium hydride. Lithium hydride is actually a rather simple molecule, which does not necessarily require a quantum computer for its simulation, but it helps me to find sources for potential measurement and calculation errors. This will help me in the future to write better algorithms that can avoid them, in order to process more complex calculations without errors. I am working on a kind of workaround and see what the system can do and how to program it optimally to get the best possible results.

How did you learn to work with a quantum computer?

Special software is needed to program and control quantum computers. I use “Qiskit” from IBM. However, for a proper operation one must not only understand the program, but also the functioning of quantum computers. To learn this, I participated in the “Qiskit Global Summer School 2020” of IBM. It was supposed to be a rather small event with 200 people, but the demand was so great that in the end there were 4000 participants. It lasted for two weeks and was a great training that, in addition to the content that would have been enough for a whole semester, also sparked passion for quantum computing.

What are the advantages of qubits based on nitrogen vacancy centers compared to the currently used qubit technologies?

Various research groups have already been able to prove that the coherency time, i.e. the time a quantum state is preserved and available for calculations, is much longer for nitrogen-vacancy centers in diamond. Moreover, it has been shown that this is also the case at higher temperatures, no longer in the millikelvin range. Therefore, it is hoped to build even better quantum computers based on nitrogen-vacancy centers in diamond, which will allow longer computational operations and be more robust. 

What do you like most about Freiburg and what is your favorite spot?

I like the beautiful city center and that Freiburg has a bit of big city flair without being one. My favorite place is the botanical garden. Unfortunately, the greenhouse – my personal highlight – cannot be visited right now, but the outdoor area is beautifully designed as well and can always be enjoyed.

Kathrin König studied microsystem engineering at IMTEK in Freiburg and joined Fraunhofer IAF as a master student in 2019. After writing her thesis on GaN half bridges, she switched to the field of Quantum technology research and started her dissertation in 2020.