Frontiers of Science: Søren Fournais and Jan Philip Solovej
Søren Fournais and Jan Philip Solovej receive the 2026 Frontiers of Science Award at the International Congress of Basic Science in August in recognition of the results published in their joint article “The energy of dilute Bose gases” in Annals of Mathematics from 2020.
The 2020 article solves a major open problem in mathematical physics. It concerns Bose–Einstein condensates. This new possible state of physical systems was theoretically predicted by Bose and Einstein in 1924–25, but it was only experimentally possible to realize them in very cold atomic gases of low density in the 1990s. The article proves a formula for the energy of such a low-density Bose gas.
This had been a central and famous problem in mathematical physics since 1957, when Dyson and Lee, Huang, and Yang published fundamental papers on the subject.
Collaboration, some sleepless nights – and more collaboration
Søren Fournais emphasises that successfully proving the formula was the result of a long collaboration. There were almost daily video calls where each day’s progress and setbacks were discussed.
Some ideas were too good to be true: at one point, they believed they could prove an even stronger version of the formula. After a few days, though, they found the flaw in the argument, which led to some sleepless nights trying to make it work.
However, the core of the argument was salvaged, and this became the paper in Annals. After several additional years of work, they succeeded - using a different and longer argument - in proving the stronger version. This was published in 2023 in Inventiones mathematicae.
The awardees focus on the community
Søren Fournais will be going to Beijing in August to receive the award. Both Søren and Jan Philip express their delight and are, of course, pleased with the personal recognition, but perhaps even more with the additional visibility it creates for mathematical research in general and for the Centre for the Mathematics of Quantum Theory (QMATH) in particular.
Their hope is that the award will contribute inspiration to all the very talented PhD students and postdocs continuously contributing new insights to the field.
About the award
The International Congress for Basic Science honours top research, with an emphasis on achievements from the past ten years which are both excellent and of outstanding scholarly value. For the 2026 selection, scientific works in both basic and applied research were chosen in 40 areas of the three basic science fields (mathematics, theoretical physics, and theoretical computer and information sciences) represented at the ICBS.