Title: Emergence of epithelial cell density waves,
Abstract: Epithelial cell monolayers exhibit traveling mechanical waves. We rationalize
this observation thanks to a hydrodynamic description of the monolayer as a
compressible, active and polar material. We show that propagating waves of the
cell density, polarity, velocity and stress fields may be due to a Hopf
bifurcation occurring above threshold values of active coupling coefficients.