Motion of two micro-wedges in a turbulent bacterial bath

The motion of a pair of micro-wedges (“carriers”) in a turbulent bacterial bath is explored using computer simulations with explicit modeling of the bacteria and experiments. The orientation of the two micro-wedges is fixed by an external magnetic field but the translational coordinates can move freely as induced by the bacterial bath. As a result, two carriers of same orientation move such that their mutual distance decreases, while they drift apart for an anti-parallel orientation. Eventually the two carriers stack on each other with no intervening bacteria exhibiting a stable dynamical mode where the two micro-wedges follow each other with the same velocity. These findings are in qualitative agreement with experiment on two micro-wedges in a bacterial bath. Our results provide insight into understanding self-assembly of many micro-wedges in an active bath.