8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P10.20Tue 611:23-14:00Effective interactions in an active bathClaudio Maggi, 1 Luca Angelani, 1 and Roberto Di Leonardo 21 University of Rome ”Sapienza”, Piazzale A. Moro, 2, 00185, Rome, Italy2 University of Rome ”Sapienza” and CNR-IPCF, Rome, ItalyActive Brownian motion in a bath of self-propelled particles is receiving a lot of attention in thecontext of non-equilibrium statistical mechanics. Here we demonstrate that active baths are alsocapable of mediating effective interactions between suspended bodies. In particular we observethat a bath of swimming bacteria gives rise to a short range attraction reminding of depletionforces in equilibrium colloidal suspensions. We call this novel interaction ”active depletion” anduse numerical simulations and experiments to quantify its nature and strength.20