Circle Swimmers in complex environments

• Applicant: Dr. Iman Abdoli, Ph.D.
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556762905

Circle swimmers are a class of mesoscopic particles that exhibit self-propelled motion in fluids, typically characterised by their ability to move in spiral or helical trajectories. This chirality, or asymmetry in their motion, sets them apart from other types of microswimmers, which typically move in straight lines or follow simpler trajectories. The motion of circle swimmers is driven by a variety of mechanisms, depending on their design and the environment in which they operate. Common driving forces include chemical reactions, magnetic fields, or light, which can induce motion through changes in the swimmer's surface chemistry, physical shape, or by generating force asymmetries in the surrounding fluid. Circle swimmers are of significant interest in fields such as microfluidics, biomedical engineering, and materials science due to their potential applications. For example, they can be used for targeted drug delivery, where their unique movement patterns allow them to navigate through complex fluidic environments in the human body where the confinements become important. They are also studied for their ability to mimic biological processes and for the potential to assemble into complex structures with advanced functionalities. The understanding of boundary effects is crucial to study circle swimmers in complex environments. The goal of this proposal is to provide a theoretical understanding of the effect of confining boundaries like walls or obstacles on circle swimmers, how stochastic effects such as random resetting of their position can influence their collective behaviour and efficiency in the study of searching problems, and finally the understanding of their collective behaviour in many body systems. We plan to use theoretical and numerical tools from statistical physics to address these questions.

• DFG Programme: WBP Position