School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran.
School of Nano Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran.
Sci Rep. 2021 Nov 29;11(1):23100. doi: 10.1038/s41598-021-02295-y.
Using Brownian Dynamics simulations, we study effective interactions mediated between two identical and impermeable disks (inclusions) immersed in a bath of identical, active (self-propelled), Brownian rods in two spatial dimensions, by assuming that the self-propulsion axis of the rods may generally deviate from their longitudinal axis. When the self-propulsion is transverse (perpendicular to the rod axis), the accumulation of active rods around the inclusions is significantly enhanced, causing a more expansive steric layering (ring formation) of the rods around the inclusions, as compared with the reference case of longitudinally self-propelling rods. As a result, the transversally self-propelling rods also mediate a significantly longer ranged effective interaction between the inclusions. The bath-mediated interaction arises due to the overlaps between the active-rod rings formed around the inclusions, as they are brought into small separations. When the self-propulsion axis is tilted relative to the rod axis, we find an asymmetric imbalance of active-rod accumulation around the inclusion dimer. This leads to a noncentral interaction, featuring an anti-parallel pair of transverse force components and, hence, a bath-mediated torque on the dimer.
我们通过布朗动力学模拟研究了两个相同且不可渗透的圆盘（包含物）在二维空间中浸没于相同的主动（自推进）布朗棒浴中的有效相互作用，假设棒的自推进轴可以偏离其纵轴。当自推进是横向（垂直于棒轴）时，主动棒在包含物周围的积累显著增强，导致棒在包含物周围的扩展位错层（环形成）比参考情况下的纵向自推进棒更明显。因此，横向自推进棒也介导了包含物之间的有效相互作用的范围显著增加。浴介导的相互作用是由于当包含物被带入小的分离时，它们周围形成的主动棒环之间的重叠。当自推进轴相对于棒轴倾斜时，我们发现包含物二聚体周围的主动棒积累存在不对称的不平衡。这导致非中心相互作用，其特征是一对横向力分量的反平行，因此，对二聚体有浴介导的扭矩。
