Johannes researches the unknown universe

"What motivates me in research is the hope that I can figure out something brand new in physics" - PhD student Johannes Røsok Eskilt.

portrait photo of Phd student Johannes Eskilt
Johannes Røsok Eskilt, PhD student at the Institute of Theoretical Astrophysics, UiO. Photo: ITA/UiO.

– My name is Johannes Røsok Eskilt, and I’m from a small island 1.5 hours south of Oslo called Tjøme. 

Before joining the University of Oslo in October 2020, Johannes did a master’s degree in condensed matter physics at the Norwegian University of Science and Technology (NTNU).

Pen-and-paper physics

– At NTNU I did my master’s project on superconductors. I realised that I enjoyed doing paper and pen calculations, and I wanted to get a better understanding of how the universe works on a fundamental level, confesses Johannes. 

So, he flew to the UK where he studied quantum field theory and general relativity.

– This project was done without writing a single line of code, everything was pen-and-paper physics, which is very different from my life now where I code almost every day, he adds.

– I really enjoyed my master’s, and it felt natural that the next step for me should be to do a PhD. I also wanted to learn more about gravity and cosmology, so I applied for the Institute of Theoretical Astrophysics and here I am, he concludes.

Faint signal from the young universe

At the Institute of Theoretical Astrophysics (ITA), Johannes is a PhD candidate of the CMB&CO group within the Cosmology and Extragalactic Astronomy section.

– The best thing about a PhD is the freedom you get. Right now, I am working on maybe four different projects. The one I am most excited about is the cosmic birefringence project, comments Johannes.

A year ago some researchers claimed that the polarisation angle of photons coming from the cosmic microwave background have rotated as they have travelled for 14 billion years. They reported that it has rotated by a third of a degree, so it is a very faint signal.

illustration showing the birefringence effect of the cosmic microwave background
Cosmic birefringence is the effect that the polarisation of light coming from the CMB has rotated as it has travelled through the universe. This effect has not been proven to exist yet, but we researchers are working hard on figuring out if this effect can be seen in the Planck satellite data. Credits: Y. Minami / KEK.

– I have been working closely with these researchers and many more to see if their original result holds up, and we will publish our findings very soon. It’s going to be exciting to see what other researchers will think of our paper, he says thrilled.

– How have you accomplished that?

– In the project described above, there was both a mix of theory and data analysis which I enjoyed. If cosmic birefringence holds true, it would mean the standard model of physics would have to be changed, and so there is a great deal of theoretical motivation that my background in fundamental research has helped me appreciate.

– Most of the work has however been writing the Python code to analyse the cosmic microwave background data as measured by the Planck satellite.

Revealing the unseen physics

– What fascinates you about your research?

– As a theoretical physicist my goal is to help reveal new, unseen physics.

For instance, scientists know that about 70% of the universe is made out of dark energy, but they have no idea what dark energy is.  

– In one of my projects I try to make a mathematical model of what dark energy could be. This is a great example of what motivates me in research: the hope that I can figure out something brand new in physics. 

Family and friends to the rescue

Johannes with his friends at a fotball match in Berkeley
During his Masters, Johannes spent a year abroad at University of California – Berkeley, an experience with many good memories. Photo: private.

Johannes moved back to Norway because he wanted to be close to his family and a his friends. 

– In addition, doing a PhD other places in Europe does not pay very well either. In fact, in London I would most likely have been required to pay tuition for doing my PhD, he explains.

– What is your experience at ITA so far?

– My experience at ITA has been mostly good! But I did start my PhD during a pandemic, and the winter was filled with very strong restrictions. Luckily, I have good friends in Oslo, and so I managed. But it certainly wasn’t the best possible start.

When the corona-restrictions were lifted, Johannes could enjoy the city a lot more.

– And I enjoy coming in to the office and meeting my colleagues. It is nice to see everyone’s faces in real life and not just on Zoom.

– Any expectations?

– I hope that my years at ITA will give me many opportunities once I am done, whether that is in academia or the industry. And I will also of course appreciate all the friends and connections I have gotten working at the institute, Johannes ends.

Tags: Cosmic Microwave Background (CMB), Cosmology, Universe, PhD life By Martina D'Angelo
Published Jan. 7, 2022 8:59 AM - Last modified Jan. 10, 2022 10:39 AM