Tamás Vámi interviews Scientific Chairman Lars Bergström

Professor Lars Bergström is one of the two scientific chairmen of the 66th Lindau Nobel Laureate Meeting (alongside Prof. Rainer Blatt). The theoretical physicist from the University of Stockholm is a member of the Physics Section fo the Royal Swedish Academy and also serves as a deputy board member of the Nobel Foundation. His interviewer, Hungarian Tamás Vámi, is a particle physicist at CERN and one of almost 400 young scientists taking part in this year’s Lindau Meeting.

Tamás: Lars, you are one of the two scientific chairmen of this year’s Lindau Meeting. What can we expect from the scientific programme of #LiNo16?

Lars Bergström: I think we will see a vibrant programme with many memorable talks. Of course it is especially gratifying that the most recent Physics Laureates are present, and that also many Laureates in Chemistry contribute to the programme. Taken as a whole, this year we will have excellent overviews of diverse scientific areas from the persons who were instrumental in creating them. 

Tamás: There are many candidates for Dark Matter. Which model is closest to your heart, which is the one that is the most promising in your opinion?

Lars Bergström: This is a difficult question. Experience tells us that in science it is not always good to “fall in love” with a particular theoretical model. I think the answer is at the moment in the hands of our brilliant experimentalists, and we have to keep an open mind and see what they find. Weakly interacting massive particles (WIMPs) and axions belong to the most studied dark matter candidates, but nature could be more subtle.

Tamás: Dark Energy is one of the biggest mysteries of our days. There are many theories about it, but what are the experimental methods of studying it?

Lars Bergström: The thing that distinguishes dark energy from dark matter is that dark matter is gravitationally attractive, whereas dark energy on the contrary is repulsive. This means that the expansion of the universe, which would slow down if there was only matter present, will instead accelerate. This accelerated expansion can be seen on very large length scales as it e.g. makes distant supernovas dimmer than they would otherwise appear. It seems, however, to be very difficult to see effects of dark energy locally, such as in the solar system.

Tamás: 2016 is certainly a very exciting year for science: The LIGO experiment announced the detection of gravitational waves and there is a sign of new physics at the LHC with the „750 GeV bump“. How do you think these announcements could affect your field? (eg. gravitational waves – dark energy connection?, 750 GeV bump – dark matter connection?)

Lars Bergström: I do not think it will affect either the modeling of dark energy, or enter the explanation of the tentative 750 GeV resonance. However, a new subfield of astroparticle physics and cosmology will likely be created: gravitational astronomy. Here one would study some of the most extreme events happening inside and outside our galaxy, like the merger of neutron stars or of black holes. This is an unchartered area where many surprises may be hiding.

Tamás: Are there any possible breakthroughs in Science that you wish to live to see? What is it and why do you think it is important?

Lars Bergström: Having worked for three decades with the dark matter problem, the identification of the particle constituting dark matter would be highest on my wish list. Then there are many areas of quantum physics, like quantum communication or quantum computing, where breakthroughs may happen that could even change our everyday lives. But of course many discoveries and inventions have been total surprises, and maybe that is how progress will be made. The young scientists at #LiNo16 live at a time when they can make use of past achievements to make such breakthroughs – if they just remember to be bold and creative, like the Laureates were that they will get in touch with here in Lindau! 

Tamás: How do you see the role of the individual vs. collaborations in Science?

Lars Bergström: Collaborations are of course made up of individuals, and in physics we often need very large collaborations to make progress, e.g. in particle physics or cosmology. Fortunately, for the Nobel Prizes in Physics, it has so far been possible to identify at most three persons that were crucial for the awarded discovery or invention, and hopefully that will be possible, although perhaps more difficult,  in the future.