Interview with Mattias Blennow

Hello Mattias, tell us a bit about you, where do you come from, your academic studies etc.? 

I was born and raised in Stockholm and studied Engineering, Physics and did my PhD in Theoretical Physics at KTH. I then left KTH to do postdocs in Germany at the Max-Planck-Institutes for Physics and Nuclear Physics in Munich and Heidelberg, respectively, for 4.5 years in total. In 2012 I returned to KTH as an assistant professor, where I have continued to develop my teaching and research apart from a sabbatical at the Instituto de Fisica Teorica in Madrid in the academic year 17/18.

Taking up a new position is a challenge on its own. How has your time as a professor been so far, any significant changes compared to your previous position?

My time as a professor has so far has been very different from my previous work since I was promoted during parental leave, which does offer an entirely new experience. As far as any changes to my academic work are concerned, I am looking forward to facing any new challenges when I return to work in April 2022.

Tell us about your research; what makes it essential?

I am working mainly in fundamental physics theory and phenomenology of very weakly interacting elementary particles, neutrinos, and dark matter. These two fields contain some of the few hints for physics beyond the Standard Model. While neutrinos are part of the Standard Model, they were discovered to have non-zero masses as late as 1998, which is something that requires extending the model. Meanwhile, astronomical and cosmological observations indicate that a majority of the mass in the The Universe cannot be in the form of Standard Model particles, so-called dark matter. The model, therefore, needs to be extended to accommodate a dark matter candidate. My research involves theoretical extensions of the Standard Model as well as considering their signatures in current and future experiments to ultimately discover how the Universe behaves at the very smallest of scales.

What are the biggest challenges your research combats?

Experiments in particle physics of today is necessarily done in large international collaborations and are enormous undertakings. Even the smallest viable experiments require large apparatuses with time scales on the order of decades, not to mention the herculean task of collider particle physics performed at the Large Hadron Collider. As such, new experimental results are relatively scarce and far between. Significant results are being published at a steady but relatively slow rate. Because of this, there are often many competing theories for Standard Model extensions and the only way of discriminating among them is through experimentation.

Does your work have practical applications? If so, what would those be?

By design, elementary particle physics is very much fundamental research and any practical applications, therefore, lie far in the future. If history has taught us anything, though, it is that what is fundamental research today often finds its way into practical applications eventually.

Has your work been affected by the pandemic, and if yes, how?

As many of the teachers at KTH, my teaching has of course, been significantly affected by the pandemic and the resulting distance teaching, which has taken a lot of focus (perhaps at the expense of research). Luckily, I already had some experience in producing online teaching material and therefore had a bit of a head start when it all begun. My research work is mainly theoretical, often being done analytically or through computer simulation in smaller focused groups of researchers at different universities. As such, we were already communicating electronically to a large extent, and I would say the impact on how the work is being done was relatively small. I have however missed the physical meetings with other faculty, postdocs, and Ph.D. students at KTH.

 Why did you choose your field of research in particular?

 I was very interested in particle physics already at high school after my grandmother gave me a book by Stephen Hawking for Christmas. It was therefore no surprise that I ended up in particle physics even if I wavered a bit in the direction of mathematics early in my studies. I consistently made choices in my studies to bring me closer to particle physics and ended up doing my Master Thesis in neutrino physics, which is also what I built my Ph.D. thesis upon. Through my postdoc years I started diversifying beyond the Standard Model physics in general as it was a natural extension of my acquired expertise.

What made you interested in your field?

That the world of elementary particles seemed so wondrously strange and different from what we experience at the macroscopic scale.

Is it important for you to communicate your research to the world if yes why and how do you do that?

Yes, I believe a very important part of justifying fundamental research is to communicate it to the public. I have given and written several popular scientific talks and articles about my research and related topics and developed online courses directed at a general audience. I try to make sure that any online teaching material is as openly available as possible.

What would be your message or advice to interested youngsters in perusing scientific professions?

I think this is a very complex question that deserves more than a short answer. The best short message would be that a scientific career can be very hard, but also very rewarding. Do not focus entirely on a particular field just because you think it sounds cool in popular science descriptions. Be open to other paths if it turns out that the actual work being done along those paths seems more exciting or rewarding than that which you had your thoughts on from the beginning. Being passionate about what you do makes everything a lot easier.

Text: Elina Charatsidou