Swimming microorganisms represent fascinating exemplars of non-equilibrium systems. These active agents often operate in complex environments that can strongly modify their swimming dynamics. In this talk, I will discuss the first-passage-time statistics of active Brownian particles moving in a confined channel [1]. Exploiting Siegmung duality, we derive analytical predictions for the time-dependent propagator in the regime of small activity, which approaches a wall-accumulated stationary state, reminiscent of experiments of bacteria. Second, I will focus on the impact of heterogeneous flows on active transport through a disordered, porous channel [2]. While in the absence of flow agents accumulate at boundaries, flow vorticity also generates extended trapping phases of microswimmers in areas of the flow backbone, leading to prominent power-law tails in the exit-time distributions. Our results highlight how self-propulsion and hydrodynamic couplings impact spreading and search efficiency in active systems.
[1] Y. Baouche*, M. Guéneau*, C. Kurzthaler, arxiv:2603.12080
[2] P. Das et al., arXiv:2511.02471