Almost everyone is fascinated by ants; their numbers, cooperative skills, efficiency, apparent know-how and elegance are just too difficult to miss. Dropping to your knees for a closer look may prove to be counterproductive: interactions are too many to grasp, individual ants are difficult to follow, and when one finally manages to focus on one - she often appears to be somewhat disoriented. Such characteristics describe much of the biological world as it is composed of dense, communicating, and difficult to understand ensembles. In our lab we combine experiments with theory, lab with field work, technological solutions with data analysis, and pencil scribbling with nest digging to try and take on the challenging task of observing ants.
Gompper G., Stone H. A., Kurzthaler C., Saintillan D., Peruani F., Fedosov D. A., Auth T., Cottin-Bizonne C., Ybert C., Clément E., Darnige T., Lindner A., Goldstein R. E., Liebchen B., Binysh J., Souslov A., Isa L., di Leonardo R., Frangipane G., Gu H., Nelson B. J., Brauns F., Marchetti M. C., Cichos F., Heuthe V. L., Bechinger C., Korman A., Feinerman O., Cavagna A., Giardina I., Jeckel H. & Drescher K.
(2025)
Journal of Physics Condensed Matter.
37,
14,
143501.
Activity and autonomous motion are fundamental aspects of many living and engineering systems. Here, the scale of biological agents covers a wide range, from nanomotors, cytoskeleton, and cells, to insects, fish, birds, and people. Inspired by biological active systems, various types of autonomous synthetic nano- and micromachines have been designed, which provide the basis for multifunctional, highly responsive, intelligent active materials. A major challenge for understanding and designing active matter is their inherent non-equilibrium nature due to persistent energy consumption, which invalidates equilibrium concepts such as free energy, detailed balance, and time-reversal symmetry. Furthermore, interactions in ensembles of active agents are often non-additive and non-reciprocal. An important aspect of biological agents is their ability to sense the environment, process this information, and adjust their motion accordingly. It is an important goal for the engineering of micro-robotic systems to achieve similar functionality. Many fundamental properties of motile active matter are by now reasonably well understood and under control. Thus, the ground is now prepared for the study of physical aspects and mechanisms of motion in complex environments, the behavior of systems with new physical features like chirality, the development of novel micromachines and microbots, the emergent collective behavior and swarming of intelligent self-propelled particles, and particular features of microbial systems. The vast complexity of phenomena and mechanisms involved in the self-organization and dynamics of motile active matter poses major challenges, which can only be addressed by a truly interdisciplinary effort involving scientists from biology, chemistry, ecology, engineering, mathematics, and physics. The 2025 motile active matter roadmap of Journal of Physics: Condensed Matter reviews the current state of the art of the field and provides guidance for further progress in this fascinating research area.
Dreyer T., Haluts A., Korman A., Gov N., Fonio E. & Feinerman O.
(2025)
Proceedings of the National Academy of Sciences - PNAS.
122,
1,
e241427412.
Biological ensembles use collective intelligence to tackle challenges together, but suboptimal coordination can undermine the effectiveness of group cognition. Testing whether collective cognition exceeds that of the individual is often impractical since different organizational scales tend to face disjoint problems. One exception is the problem of navigating large loads through complex environments and toward a given target. People and ants stand out in their ability to efficiently perform this task not just individually but also as a group. This provides a rare opportunity to empirically compare problem-solving skills and cognitive traits across species and group sizes. Here, we challenge people and ants with the same "piano-movers" load maneuvering puzzle and show that while ants perform more efficiently in larger groups, the opposite is true for humans. We find that although individual ants cannot grasp the global nature of the puzzle, their collective motion translates into emergent cognitive skills. They encode short-term memory in their internally ordered state and this allows for enhanced group performance. People comprehend the puzzle in a way that allows them to explore a reduced search space and, on average, outperform ants. However, when communication is restricted, groups of people resort to the most obvious maneuvers to facilitate consensus. This is reminiscent of ant behavior, and negatively impacts their performance. Our results exemplify how simple minds can easily enjoy scalability while complex brains require extensive communication to cooperate efficiently.
Sevostianov I. & Feinerman O.
(2024)
Entropy.
26,
11,
916.
The concept of emergence, or synergy in its simplest form, is widely used but lacks a rigorous definition. Our work connects information and set theory to uncover the mathematical nature of synergy as the failure of distributivity. For the trivial case of discrete random variables, we explore whether and how it is possible to get more information out of lesser parts. The approach is inspired by the role of set theory as the fundamental description of partwhole relations. If taken unaltered, synergistic behavior is forbidden by the set-theoretic axioms. However, random variables are not a perfect analogy of sets: we formalize the distinction, highlighting a single broken axiomunion/intersection distributivity. Nevertheless, it remains possible to describe information using Venn-type diagrams. The proposed multivariate theory resolves the persistent self-contradiction of partial information decomposition and reinstates it as a primary route toward a rigorous definition of emergence. Our results suggest that non-distributive variants of set theory may be used to describe emergent physical systems.
