Multistability and Tipping: From Mathematics and Physics to Climate and Brain

Report on the Seminar and Workshop Program

Multistability and Tipping: From Mathematics and Physics to Climate and Brain

According to the goal of this workshop/seminar we brought together scientists from various disciplines of natural sciences, such as mathematics, physics, climate science, neuroscience, ecology, systems biology and network science. Multistability has been presented in various disciplines of science including electronics, optics, mechanics, laser physics, chemistry, genetics, neuroscience, in the climate system and in ecology. Of particular interest for many applications were transitions between the different states, also called regime shifts or tipping points, which can be either due to changes in the internal parameters of the system, changes in the forcing or the influence of noise. According to the nature of the transitions they have been classified as R-tipping, B-tipping, and N-tipping. Besides studies of the dynamics depending on environmental parameters, the focus was on developing methods how to estimate the distance from a regime shift/tipping point in models as well as from time series. The concept of critical slowing down, i.e. the increase in the times necessary to return to the original state after a perturbation, has been proven to be suitable for this task.

Almost all speakers which have been invited accepted this invitation, so that most of the major players in this field were present in the workshop, some of them gave also lectures in the seminar. Due to the extremely high quality of the program we had an overwhelming number of applications and it was a pity that we were unable to accommodate all the people who were interested because of the strict number of 70 participants. We had 18 worldwide well-known invited speakers who attracted so many applications. The most famous ones among them are James A. Yorke (USA), Celso Grebogi (UK), Alan Hastings (USA), Egbert van Nes (The Netherlands), Kunihiko Kaneko (Japan), Juergen Kurths (Germany), Tamas Tel (Hungary) and Eckehard Schoell (Germany). The participants came from 19 countries. Due to this highly competitive participation at the conference the level of all talks was very high and we had lively interdisciplinary discussions leading to the intended cross-fertilization between the different fields. The two poster sessions included in the program were very busy and the young participants benefitted a lot from the discussions with the well-known senior scientists. A committee, consisting of A. Hastings, T.Tel, J.A. Yorke, E. van Nes, selected 5 posters to be awarded with a poster price. As a result of this workshop it can be expected that several joint papers with different participants of the workshop will appear in the future. We plan a Focus Issue of the international peer-reviewed journal CHAOS with 20-25 invited papers.

The seminar was equally successful thanks to the excellent lecturers we had. Lecture series have been given by J. A. Yorke, C. Kuehn, K. Kaneko, J. Kurths and the two organizers A. Pisarchik and U. Feudel. Since we had again an overwhelming number of application and could only accept 20 participants, the participation was highly competitive, so that the young people selected were extremely motivated and took part very actively. All of them used the unique opportunity to talk with the lecturers about their PhD projects. Particularly, it is worth mentioning that the students also talked a lot with each other trying to figure out topics of joint interest. Several people started new collaborations based on their interaction in the seminar.