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Dr. Nicola Tamanini - Unraveling the mysteries of gravitational waves

Dr. Tamanini is an Italian researcher, passionate about gravitational waves and the mysteries of our expanding universe. 

He is giving us an insightful outlook on his experience as a young researcher in a very competitive field.

Published on 20 September 2016

  • What is your professional experience before coming to CEA?

I graduated in Physics and Theoretical Physics at the University of Trento, Italy, before completing my PhD in Applied Mathematics at University College London. Afterwards, I found a post-doctoral position in the Theoretical Physics Institute (IPhT) hereat CEA-Saclay. I have been here for 2 years now and my stay ends in one year.

  • What is your research project about?

I am working on a cosmological project, entitled "Gravitational Waves as a New Probe of the Dark Side of the Universe". With my supervisor, Dr. Chiara Caprini, we are studying all the methods we can employ to get all sorts of information about the universe, using gravitational waves. For that purpose, we are working in close collaboration with people from the Institut d'Astrophysique de Paris and the Astroparticle & Cosmology Laboratory at Paris-Diderot University.

 In the future, we hope that more data about gravitational waves will be collected. Gravitational waves are emitted during extremely energetic processes, for instance when two black holes or two neutron stars orbit each other and end up crashing and merging. Now, with the only two gravitational waves recorded so far, we were not able to measure the velocity (more precisely the redshift) of the source, since this cannot be extracted from the gravitational wave signal, as one can instead do with the distance of the source. For that purpose, we need to analyse the electromagnetic counterpart of the events. If we manage to measure both the distance and the redshift of many events in the universe, we will be able to map how it is expanding. What we know is that the expansion of the universe is accelerating but we would like to understand what causes this acceleration, which so far has been attributed to a mysterious entity called dark energy.

The problem is that models describing the electromagnetic counterparts are not very developed, due to the lack of astrophysical information. That's why we are trying to perfect our techniques so as to be able to use electromagnetic models to exploit gravitational waves signals to the most. Our work is carried out in the perspective of a European project, called eLISA, the purpose of which is to build a space-based gravitational wave detector.

So far, I am quite happy with my work. I started working on gravitational waves since my arrival at CEA-Saclay, before it became a hot topic in the scientific community. Before that, I was working on alternative theoretical models of dark energy and modified theories of gravity. Personally, I am more interested in studying the relatively recent evolution of the universe, where dark energy plays an important role. My supervisor, on the other hand, focuses more on signals from the early universe, that is to say the gravitational wave background noise resulting from the early stages of the expansion of the universe after the Big Bang.

Most of the information we get thanks to gravitational waves are astrophysical: we gather data about the mass of binary stellar systems, the way they spin… We now would like to get cosmological information from these systems, i.e the properties that are linked with the expansion of the universe, which would ultimately lead us, ideally, to know more about dark energy.

  • What are the strengths of your stay at CEA?

I think the best aspect of my stay is the freedom I am given. As a CEA researcher, I have the opportunity and possibility to travel a lot and to attend international conferences. As a matter of fact, I am often outside Paris. This mobility allows me to build a global research network, as I get to meet many scientists from my field but also from connected fields.

For that matter, my work here taught me how to efficiently collaborate with researchers from very different fields. Indeed, for the purpose of our research project, we need various types of experts: for example astrophysicists, computational physicists, data scientists, astronomers and of course theoretical physicists, like me.

  • Do you think that the international dimension of the programme brings value to your laboratory?

I think the international dimension of a laboratory is crucial. The fact that there are both French and international researchers allows laboratories to multiply contacts and collaborations with foreign institutes and this synergy is very valuable.

On a personal level, I am also learning French, even though we speak only English with my collaborators and Italian as well, because there are a lot of Italian people here and in the research community in general. Learning French was not too complicated as it is very similar to Italian, and making French friends helped a lot. Personally I am really enjoying life in Paris.

  • All in all, what do you think about the Enhanced Eurotalents programme?

I think the Enhanced Eurotalents programme is a good opportunity for young researchers to carry out a research project over a long period of time. Thanks to the programme, I was able to stay one additional year, which allowed me to spread the funding over 3 years. Time is a fundamental parameter in science, and a lack of time can seriously hamper the achievement of a research project. Moreover, being affiliated to Enhanced Eurotalents and eLISA gives me the possibility to attend high-level conferences which is very precious for my research project and for my career.

 For all these reasons, I would definitely recommend the programme.

  • What is your plan after your postdoc here at CEA-Saclay?

I am applying for a 3-year Marie Curie fellowship to go to the USA for two years and then come back to Paris for one year with more experience on cosmology and gravitational waves. However, competition is high. If I do not get this fellowship, I will try to apply for other post-doc positions here or elsewhere as long as I can travel and work on what I like. It is very hard to get a position in general, but even more so when you want to enter a specific field – for one post-doc position, there are usually hundreds of applicants. Moreover, the status of researcher has advantages and disadvantages. If you want to keep working in a specific field, you need to move every 2 or 3 years which is culturally very enriching but also very hard to combine with personal life sometimes.​