Collective behavior of quorum-sensing run-and-tumble particles in   confinement
  We study a generic model for quorum-sensing bacteria in circular confinement. Every bacterium produces signaling molecules, the local concentration of which triggers a response when a certain threshold is reached. If this response lowers the motility then an aggregation of bacteria occurs, which differs fundamentally from standard motility-induced phase separation due to the long-ranged nature of the concentration of signal molecules. We analyze this phenomenon analytically and by numerical simulations employing two different protocols leading to stationary cluster and ring morphologies, respectively. 
Markus Rein and Nike Hein{\ss} and Friederike Schmid and Thomas Speck
cond-mat.soft cond-mat.stat-mech physics.bio-ph q-bio.CB