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Description
Active particles confined in narrow channels often explore high dimensional phase spaces where symmetry breaking mechanisms can give rise to directed transport. These particles possess persistent motion which arises from continuous conversion of energy into self-propulsion. Although this directed motion becomes inefficient in long times due to the effects of thermal and rotational diffusion, leading to random particle trajectories. Therefore, to suitably tailor active particle dynamics for practical applications, efficient methods are required to achieve directed motion. In this work we present a highly efficient mechanism based of particle-wall alignment interaction for rectification of particle transport. Using numerical simulations we show that a subtle asymmetry in strength of interaction between the opposite channel walls with particle or a gravitational bias is sufficient to break the inversion symmetry and generate directed motion of chiral active micro-swimmers with over 60% efficiency. Here, chirality refers to the presence of intrinsic angular velocity, resulting in circular trajectories in either clockwise or anti-clockwise direction along with translational motion. For achiral active particles, rectification happens only in presence an unbiased external fluid flow that perturbs the particle dynamics and introduce orbiting motion. Thus, we put achiral particles inside Couette flow to break the upside down symmetry and exhibit spontaneous directed motion. Further we have checked the robustness of rectification by our proposed method against various self-propulsion properties, particle’s intrinsic chirality and several stable velocity orientations of the particle with respect to channel walls. We believe our findings offer deep insights to gear motion of artificial as well as natural active systems.