Irreversibility and chaos in active particle suspensions

Abstract

The collective behavior of active suspensions of microswimmers immersed in a viscous fluid is investigated through numerical studies. It is shown that a bioturbulent state emerges both in suspensions of pushers and of pullers. Which conditions are needed to trigger such phenomenology and what mechanisms underlie such phenomena are discussed. An investigation into whether the difference in puller and pusher dynamics is due to a spontaneous breaking of the hydrodynamics time-reversal symmetry is presented, and the mechanisms underlying such broken symmetry in biological swimmers are examined.