When Albert Einstein predicted the existence of gravitational waves in the universe, it was little more than a theory. Solid evidence of gravitational waves was first obtained 100 years later on 14 September 2015 at the Laser Interferometer Gravitational-Wave Observatory (LIGO). They can be created if enormous energy is released as a result of cosmic events, such as the merging of black holes. At this time, Simone Bavera was studying physics at the Swiss Federal Institute of Technology in Zurich and developed an intense interest in Einstein's general theory of relativity. The evidence of gravitational waves that ultimately earned the Nobel Prize for the researchers more than whet his appetite. It was "very exciting for me," he recalled. "I was a witness to the birth of a new field in astronomy." Gravitational waves open up a new window to the universe as objects that do not emit any light, such as black holes, can now be detected. "But the greatest question remains: Where do these merging black holes originate? How do they attain their specific properties, size, rotation?" asks this native of Ticino. And it was precisely these questions that he posed in his dissertation submitted to the University of Geneva.
An inquisitive student
He investigated the coalescence of binary black holes, meaning black holes that occur in pairs and orbit around each other, and developed a model for predicting their properties. What makes his approach special is his design of physical models that he compares with data from gravitational wave observatories, something that was an impossibility prior to 2015. This was pioneering work from the doctoral student. "Simone's work was the first to enable theoretical predictions over the combined distribution of all three observables, namely the chirp mass, effective spin and redshift of mergers," writes Anastasios Fragkos, his mentor. "This work demonstrates that correlations between these observables contain significant signatures of the underlying physical processes that occur during the creation of binary black holes. They therefore provide information on their astrophysical origin."
Simone Bavera's fascination for black holes may not have begun while he was in the cradle, but it already became clear in school what he could eventually become. "I was good at mathematics, and I was always begging my teacher for additional work," he recalls. His teacher once gave him logic assignments. "This showed me just how powerful a tool mathematics was when it came to understanding the world. Filled with enthusiasm, I went home and told my parents about it. 'That's physics', they responded, indicating that it could be studied at the Swiss Federal Institute of Technology." It was then clear what he would eventually choose to study.
How humanity pushes the boundaries
"We are only beginning to scratch the surface," he says with excitement. "Why do we do what we do? Human beings are inquisitive and strive to expand their boundaries. Having first investigated our planet Earth, we then ventured beyond to explore the Moon. The discovery of gravitational waves once again pushed these boundaries out even more."
Simone Bavera still works at the University of Geneva today in his doctoral supervisor's group, heading a team that develops software for modelling binary stars. Although he loves his work, it does not devour his complete attention. "My private life is very important to me," he laughs. "I need my sleep, and I like to be free at the weekend." He likes listening to podcasts, preferably from Lex Fridman, and he loves cooking, exploring the mountains and travelling. He was in Swedish Lapland with his fiancée a few months ago. "I proposed to her there. It was freezing cold," he relates.
He almost becomes poetic when he contemplates the future. "I would like to continue pursuing the beauty of life." He will remain at the University of Geneva until at least the end of the summer, but what then? "Maybe I've reached a point in my life where I'd like to tackle tangible things." He completed a dissertation because, following his master's degree, he realised his questions had not yet been answered. New questions arose following the dissertation. "Maybe there is a new adventure waiting with new questions, and possibly even outside the academic world."