Fig. 1. Active elasticity leads to correlated velocity fields.

a Mechanisms at the origin of the active elastic theory in the energy landscape (top), inside an energy minimum (bottom left), and between particles (bottom right). b Velocity fields in simulated cell sheets. Top—System-spanning correlations in a solid soft disk system at τ = 2000. Bottom left—liquid soft disk system at τ = 200, and bottom right—SPV model simulation at τ = 200, cell outlines in white. c Velocity fields in experimental cell sheets. Top—sample experimental velocity field, overlaid over phase-contrast image of the cell sheet. Bottom left—particle-based best fit model to the experiment, including divisions and extrusions (visible as dark red arrows). Bottom right—SPV model-based best fit model to the experiment.