Prof. Dr. Frank den Hollander

Winner of the Alexander von Humboldt Research Award and guest researcher at FAU´s Chair of Mathematical Stochastics

On 29 March 2019, Prof. Frank den Hollander from Mathematisch Instituut Universiteit Leiden, received the Humboldt Research Award in a special ceremony. The Alexander von Humboldt Foundation has awarded the mathematician the prize in recognition of his research into probability theory and his dedication in initiating research networks and groups in the field of stochastics.

Prof. Dr. den Hollander’s areas of research include the theory of stochastic processes and its application in physics, biology, and computer science. In particular, his work involves the theory of large deviations, processes in random media, metastable behavior and potential theory, models of mathematical biology and random graphs. He has already been appointed as a Fellow of the Institute of Mathematical Statistics (IMS) and the American Mathematical Society in recognition of his work.

Prof. Dr. den Hollander has worked and is still working with his host at FAU, Prof. Dr. Andreas Greven at the Chair of Stochastics, on several research projects. Currently, they are investigating the evolution of genetic populations with a seed-bank as well as the evolution of genetic populations that are subject to drastic events.

Prof. Dr. Greven´s probability theory group has been internationally leading at the interface with statistical physics and population genetics.

Prof. Dr. den Hollander, in your research, you mainly focus on stochastics. What exactly sparked your interest in this field or research?

Probability theory is a very eclectic research field. It has links with many other areas in mathematics, and with other scientific fields, including statistical physics, population genetics, life sciences and complex networks. It is the combination of breadth and depth that has always fascinated me.

In September 2019, you came to FAU to work together with Prof. Dr. Greven from FAU´s Chair of Mathematical Stochastics. Could you please describe your research project?

We have been working on two projects. One project is jointly with Margriet Oomen from Leiden University, and involves the evolution of genetic populations with a seed-bank. The seed-bank acts as a reservoir in which individuals can retreat, for short or long periods of time, to become dormant and temporarily refrain from taking part in the evolution process. The effect of the seed-bank is that it enhances the genetic diversity of the population, a property that is important for survival of genetic traits. The other project is jointly with Rongfeng Sun from Singapore University, and involves the evolution of genetic populations that are subject to drastic events where a single individual can transfer its genetic trait to a very large number of other individuals. This high volatility has an effect that is opposite to that of the seed-bank: it has a tendency to lower genetic diversity.

What do you and Prof. Dr. Greven hope to achieve with your research?

A better understanding of how evolutionary forces like resampling, migration and volatility act together to determine the long-time behavior of genetic populations.

I have a longstanding, ongoing and fruitful collaboration with Prof. Greven. Spending an extended time with him in Erlangen, and with the probability theory group, is a pleasure.

What were the most important findings from your research so far?

We have managed to identify sharp thresholds for evolution parameters where crossovers occur between prevalence of mono-trait populations and prevalence of multi-trait populations, i.e., we have located the borders between loss of genetic diversity and survival of genetic diversity.

How could society benefit from your research?

There is a lot of discussion these days about climate change and sustainability. We need mathematical models to quantify crossover between diversity and non-diversity. Moreover, population genetic models can be translated to settings where there is a competition for resources. Mathematics has the power of abstraction.

What were your reasons for choosing FAU as your host institution?

I have a longstanding, ongoing and fruitful collaboration with Prof. Greven. Spending an extended time with him in Erlangen, and with the probability theory group, is a pleasure. I am happy that Prof. Greven will spend February 2020 at my Chair in Leiden as visiting Kloosterman Professor.

What do you like most about FAU?

Hospitality. Pleasant working atmosphere. High-quality office space. Friendly support. Perfect lodging facilities in the guest house.

How visible is FAU in your field of research on the international stage?

Prof. Dr. Greven´s probability theory group has been internationally leading at the interface with statistical physics and population genetics. It has been one of the major nodes in several priority programmes and research groups of the Deutsche Forschungsgemeinschaft (DFG). On 12 and 13 December a high-calibre workshop on population genetics was organised, which attracted leading researchers from around the world, both junior and senior.

Is there anything else you would like to mention?

I will return to Erlangen again in November and December of 2020.

Thank you for the interview, Prof. Dr. den Hollander.