Out-of-equilibrium interactions and collective locomotion of colloidal spheres with squirming of nematoelastic multipoles

Significance Liquid crystal (LC) colloids are fascinating soft matter systems at the interface of colloid science and LC physics. They exhibit structural similarities with many forms of active and biological matter, but they are usually studied under equilibrium conditions. Using spherical colloids, we show emergent symmetry-breaking transformations that lead to their directional locomotion driven by an external oscillating electric field. Our findings reveal dynamic reconfiguration of the elasticity-mediated out-of-equilibrium colloidal interactions, showing how repulsion can be converted into tunable attractive interactions in the out-of-equilibrium settings. Furthermore, such nematic colloids in dense dispersions show a striking effect of coherent motion collectively selecting the direction of their copropulsion, potentially enabling electro-optic effects and various technological uses.