A quorum sensing active matter in a confined geometry

Inspired by the problem of biofilm growth, we numerically investigate clustering in a two-dimensional suspension of active (Janus) particles of finite size confined in a circular cavity. Their dynamics is regulated by a non-reciprocal mechanism that causes them to switch from active to passive above a certain threshold of the perceived near-neighbor density (quorum sensing).A variety of cluster phases -- glassy, solid (hexatic) and liquid -- is observed depending on the particle dynamics at the boundary, the quorum sensing range, and the level of noise