Emergent patterns in active and biological systems

 

From swarming bacteria to herding sheep, nature is abundant with emergent patterns formed by 'active' agents that propel themselves using locally available energy. These patterns span a wide range of length scales, and such pattern-forming systems are exposed to various environmental factors. However, the effective interaction between such agents is often not derivable from potentials. Interestingly, some such non-equilibrium patterns resemble phase ordering in equilibrium thermodynamic systems. One of the broad interests of our group is to study such emergent behaviour in active and living systems. We conduct theoretical and numerical analyses by simulating particle-based models and constructing effective continuum descriptions. 
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Active filaments, chains and rods

Many active biological systems consist of filaments and chains along which active stresses are distributed. Prominent examples include beating cilia and flagella, as well as motor-driven filament assays. Elastic constraints couple the direction of the active stresses to the geometry of the filament, giving rise to a rich variety of nonequilibrium dynamical patterns. We use theoretical models and numerical simulations to investigate the individual and collective dynamics of active filaments and rods.

 

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Physics of growth and locomotion. 

Many of the biological systems in nature actively respond to sensory inputs and regulate their movements (such as growth and locomotion) accordingly. However, their response is limited by their intrinsic physical and mechanical constraints. In many cases, the observed growth shape or locomotive behavior of a given organism is a result of these two factors, namely the sensitivity to the external input and the physical constraints. We are interested in studying the diverse active movements observed in nature and trying to understand them from this perspective.