Vanessa Zema and Samuel Brem
​Van​essa Zema and Samuel Brem are the winners of the Best Thesis Award at the Department of Physics.​​​ ​Photo: Private (Vanessa Zema) and Helén Rosenfeldt

They won the Best Thesis Award

​Doctoral theses that impress – Vanessa Zema and Samuel Brem know how to write them. They are the winners of the Department of Physics' annual Best Thesis Award. Here they share their best tricks for writing a winning thesis.
The Best Thesis Award was founded in 2013 and is awarded annually to one or several doctoral students. With this award, the department wants to motivate students and at the same time show appreciation for their hard work. Two former doctoral students are awarded the prize for the Academic year 2019–2020: Vanessa Zema and Samuel Brem.

The committee's motivation is as follows:

"The award committee has decided to share this year's award for the best PhD thesis between Dr. Samuel Brem and Dr. Vanessa Zema. Their PhD theses display the high quality that we seek in doctoral research at Chalmers. Dr. Brem is awarded for the impressive scientific impact of his work; the committee appreciated also his well-structured thesis and felt it was easy to understand the results of his doctoral research and how these results connect to the challenges of his field. Dr. Zema delivered a beautifully written thesis detailing a unique combination of both experimental and theoretical work in astroparticle physics; the committee enjoyed reading her thesis, in which she managed to explain a complex subject in a very pedagogical way.”

We spoke with the two proud winners, to learn more about their research and their thoughts on how to write a winning thesis.

Vanessa Zema:
"Write it in a way that is useful for your future research"

In her thesis titled Unveiling the Nature of Dark Matter with Direct Detection Experiments, Vanessa Zema searches for galactic dark matter particles by using detectors located deep underground, and develops particle and solid state physics models to interpret the collected data.

The subject of dark matter was something she started working on during her master's studies in the University of Rome, La Sapienza. Her dissertation was developed and supported by an agreement between the Department of Physics at Chalmers and the Italian Gran Sasso Science Institute (GSSI), a doctoral school in astroparticle physics, located close to the National Laboratory of Gran Sasso, where many important dark matter experiments are located. 

How does it feel to win this award?
"Im honoured and proud. After all these years of studies this was an unexpected culmination of that path, a further satisfaction. I’m happy that my project was considered at the level of an award and that this new type of research in Chalmers is considered valuable and promising. I also wish to thank Professor Riccardo Catena, my main supervisor at Chalmers.”

Tell us more about the subject of your thesis. 
The topic of my project was the search for hypothetical particles in space of unknown nature that are expected to constitute most of the non-luminous matter in the universe – dark matter. The approach I adopted is known as dark matter direct detection, an experimental technique using detectors located underground that search for these particles directly reaching the target material of our detectors. We aim to detect dark matter looking at its interactions happening inside of our detectors, a different technique with respect to observing the products and effects of its interactions in space, a method used by telescopes and satellites.”

The committee found your thesis to be beautifully written – what can you tell us about your writing process?
In general, I like to understand things in depth and learn from what has already been studied, but also to elaborate on it and explain things in simple words. I try to write in a way, so that by reading you already have all the material and information you need to understand the subject. The effort of explaining something to others has the counter effect that you are also explaining it to yourself. It is an iterative process which clarifies and simplifies concepts. I had a group of people I collaborated with sending me comments and suggestions. I’m grateful for the long review which definitely contributed to the appreciated final result.”

What was the hardest part?
That must’ve been organizing all the different topics and chapters and coming to an understanding of the best way to explain my work and to motivate and clarify why I choose the projects I did.”

To someone about to write a thesis of their own – what is your best advice?
“In general, it’s easier to do things you find fun. Writing something down that you’ve already done may not be as interesting as doing research. Therefore, one suggestion I give is to always take notes of the research you’re doing. If you write it down in that very moment, instead of waiting years, then the process of writing the thesis is just collecting all the notes and details and writing down the stories. Write it in a way that is useful for yourself, and for your future research. Also, do not wait until the project is perfect before you send it to your advisor for feedback.” 

You were recently on Forbes Italia’s list of future leaders. What's the story behind this?
This was another great surprise. The editors of Forbes met me because they were interested in the Asimov prize organised by Francesco Vissani, a professor at GSSI, who involved me and other GSSI students as members of the scientific committee. Together we had the idea of starting a channel on the Asimov prize and on what a PhD career really is, to address in particular young people interested in science. On this occasion, they considered and collected information on my career and they shortlisted me for the Forbes list. I am still astonished.”

You’re now a postdoctoral researcher at Max Planck Institute for Physics in Munich. What are you currently working on?
As a result of my PhD, we reached a better understanding on how Cosinus detectors work. Now I’m working here given the result of my PhD thesis and we are optimizing the detector, using the knowledge we collected and the results we obtained. My project here is a continuation of my PhD research, I’m still searching for dark matter using direct detection technique and it is a great pleasure to still collaborate with the same people as I did during my PhD.”

Samuel Brem:
"Invest in thinking about a good structure for the thesis"

In his thesis titled Microscopic Theory of Exciton Dynamics in Two-Dimensional Materials​, Samuel Brem uses theoretical models and computer simulations to explore the properties and dynamics of excitations in two-dimensional quantum materials. He encountered the subject during his bachelor's and master's studies at the Department of Physics at Chalmers.

How does it feel to win this award?
It feels great, of course. It’s always difficult as a theoretical physicist to share your advances with people from other fields, but an award is something everyone understands.  It’s a good feeling to be appreciated.”

How come you choose this subject for your thesis? 
I was working with Professor Ermin Malic before my PhD, on my bachelor’s and master’s. Excitons and two-dimensional materials are the research focus of Professor Malic and during my time as a student I got very fascinated by this branch of theoretical physics. That’s why I chose to work with him also during my PhD. Condensed matter physics is a field where you can observe very interesting physics, including phenomena from all branches of physics like electromagnetism, thermodynimcs and of course quantummechanics. On top of that the relatively new field of nanomaterials offers a lot of interesting physical effects yet to be discovered.”

Tell us more – what are excitons?
Excitons are particles that are created when a material is excited with light. There are different classes of materials; metals, insulating materials that don’t conduct electricity, and then there’s something in between called semiconductors. When you excite these semiconductors with light, you can lift electrons into a conducting state and the material becomes conducting. The exciton is an electron paired with the hole it leaves behind when it is excited; a bound pair of a positively and a negatively charged particle. In normal materials these pairs are only stable at very low temperatures, but when you excite quantum materials -extremely thin films of material-, excitons are created that are stable even at room temperature.

The idea is that excitons could be used to build new types of electronics, called excitonics. So instead of using electrons for information processing and storage, one could instead use excitons. With that comes a lot of opportunities to improve the performance and efficiency of electronic devices.”

What do you think made your thesis appreciated by the committee?
“They said they chose my thesis because of the large scientific impact it had, I think I had something like thirty publications which I think only very few PhD students have.”

The committee also said your thesis was well-structured and easy to understand. What are your tricks?
“When writing a text, I always try to imagine explaining something to a study colleague who understands physics but maybe hasn’t worked in my field. I did a lot of teaching during my bachelor and master’s times, and during my time at the university of Berlin I was a tutor in theoretical physics, so I guess I had some practice in explaining.”

To someone about to write a thesis of their own – what is your best advice?
“Take your time and invest in thinking about a good structure for the thesis. It’s much easier to write when the structure makes sense didactically. It’s always good to make lots of figures, not only graphs but also small sketches showing the concept you’re trying to explain.”

What was the most difficult part?
Trying to make things short, but at the same time trying to say everything you want to say. To condense four years of work to the most important thing in a concise way is the most difficult.”

What are you doing now?
I’m a post doc at the University of Marburg. Ermin Malic, the professor I made my PhD with, moved here and I moved to. I continue to do my research in a similar field, and I’m now doing my best on becoming a professor!”

Text: Lisa Gahnertz

About the Best Thesis Award

The Best Thesis Award was founded in 2013, as one among several initiatives at the Department of Physics, to maintain and improve the research quality, as well as to show appreciation for the PhD students' hard work.
The management of the department also hopes that this award can help doctoral students receive an extra boost in their careers after the defense. These particular theses can serve as good examples for doctoral students in the early stages of their own thesis writing. Besides the honor, the award consists of a diploma and a monetary prize of SEK 10.000.

​Prize committee for this year’s award: Yasmine Sassa, Timur Shegai, Philippe Tassin (chairman), Mattias Thuvander, Paolo Vinai, Björn Wickman and Julia Wiktor.

Page manager Published: Tue 18 May 2021.