The human eye is bored by monotonous landscapes. We are depressed by gray skies,
unending plains under the wing of an airliner, featureless urban sprawl, geometric …

Active processes drive biological dynamics across various scales and include subcellular
cytoskeletal remodelling, tissue development in embryogenesis and the population-level …

Topological defects are at the root of the large-scale organization of liquid crystals. In two-
dimensional active nematics, two classes of topological defects of charges±1/2 are known to …

Topological defects and smooth excitations determine the properties of systems showing
collective order. We introduce a generic non-singular field theory that comprehensively …

How active stresses generated by molecular motors set the large-scale mechanics of the cell
cytoskeleton remains poorly understood. Here, we combine experiments and theory to …

Topological defects play a central role in the physics of many materials, including magnets,
superconductors and liquid crystals. In active fluids, defects become autonomous particles …

We study the dynamics of topological defects in active nematic films with spatially varying
activity and consider two set-ups:(i) a constant activity gradient and (ii) a sharp jump in …

Polar active matter of self-propelled particles sustain spontaneous flows through the full-
integer topological defects. We study theoretically the incompressible flow profiles around±1 …

The structure and dynamics of important biological quasi-two-dimensional systems, ranging
from cytoskeletal gels to tissues, are controlled by nematic order, defects and activity …

Spontaneous pattern formation in nonlinear dissipative systems far from equilibrium is a
paradigmatic case of emergent behaviour associated with complex systems. It is …