Collective deformation of anisotropic particles with internal pulsation

Capturing the emergence of deformation waves in contractile living tissues is a challenge that has recently been tackled with models of actively deformable particles. Inspired by the anisotropic deformation of cardiomyocytes in cardiac tissues, we examine how the pulsation of elliptical particles affects their collective properties in dense assemblies. We introduce two types of deformation where the eccentricity of each particle is subject to a periodic drive, and examine the interplay between nematic order and synchronized deformation via a systematic phase diagram. We derive a hydrodynamic description through a coarse-graining procedure, and show that it qualitatively captures the main collective states of the microscopic dynamics. Overall, our model provides key insights into how an active anisotropic deformation yields waves that self-organize into various dynamical patterns.