The role of deformability in determining mobility in thermal and active liquids

The mobility of cells in tissues and of soft particles in emulsions, foams, and other soft matter is determined by a complex interplay between particle shape and deformability. To understand and predict the mobility of non-spherical, deformable particles, we compare the mobility of rigid versus deformable, non-spherical particles driven by active forces and thermal fluctuations, which allows us to disentangle the roles of shape and deformability in determining particle transport. Are non-spherical particles more mobile? Or do particles with larger mobilities typically deform more from a spherical shape? Using discrete element method simulations, we will compare the long-time diffusion coefficient and the mobility in response to a small external force in dense liquids of soft particles with rigid shapes, including spheres, ellipses, and asymmetric dimers, to the same measurements for systems of particles with similar shapes, but explicit deformability. We show the results for the diffusion coefficient and mobility as a function of the packing fraction, temperature, and activity.