Research Projects

Helical magnetic nanoswimmers form a unique colloidal system which can be driven non-invasively in fluids and gels (including in vivo) using magnetic fields with great control and precision. The same system, under suitable magnetic drive, can be rendered self-propelled and form a new class of active matter, as shown recently (G. Patil et al., Phys Rev Lett 2022) by one of the PIs. The fluid flow generated by a single swimmer, as obtained from recent theoretical and experimental investigations (M. Pal et al., Phys Rev Research 2022), can be described by a system of distributed rotlets up to a good degree of approximation. This implies the hydrodynamic interaction between the swimmers must be quite different from the standard pusher-puller models used in standard treatment of active matter, but rather dominated by a strong lateral flow. Here, through detailed numerical and field-theoretical modelling efforts coupled with experiments, we wish to understand the phase diagram of this unique experimental system as a function of their activity and interaction strength. Our investigation can open new theoretical directions in Active Matter and lead to novel control strategies that will be relevant to applications of magnetic swimmers, such as better focussing toward a target, movement around obstacles: all of which are relevant to biomedical applications that are currently being pursued in this experimental system.