可形变自驱动粒子在不对称周期管中的定向输运

Directed transport of deformable self-propulsion particles in an asymmetric periodic channel

粒子的随机运动被整流为定向运动是非平衡统计物理的重要研究内容.尽管如此,在活性粒子整流的研究中,粒子通常被视为刚性的.然而,在软物质中,粒子通常具有可变形的性质.本文重点探讨了可形变自驱动粒子在非对称周期通道中的定向运输行为.由于这些粒子具有可变形的特性,它们可以通过比自身小的通道.本文通过数值计算发现,可形变自驱动粒子能够打破热力学平衡,在空间不对称的条件下产生定向运动.粒子的集体运动方向完全由通道的不对称性决定.本文还发现,增加自驱动速度和粒子软化都能促进粒子的整流,而增大密度和旋转扩散则会阻碍粒子的定向运动.本文的研究成果有助于理解可形变粒子在受限结构中的定向运动行为,并为相关软物质马达的实验研究提供理论支持.

Molecular motor can effectively convert chemical energy into mechanical energy in living organisms,and its research is currently at the forefront of study in biology and physics.The dynamic process of its guided movement,along with the crucial role they play in intra-cellular material transport,has significantly aroused the interest of many researchers.Theoretical and experimental researches have allowed detailed examinations of the motion attributes of these molecular motors.The Brownian ratchet model important.It provides an illustration of a non-equilibrium system that transforms thermal fluctuation into guided transport by utilizing temporal or spatial asymmetry.The mechanism has been extensively explored and studied across fields including physics,biology and nanotechnology.Investigations into a variety of ratchets and identification of optimum conditions contribute to a deeper understanding of guided Brownian particle transport.Preceding studies on ratchet systems largely concentrated on the rectification motions of diverse types of particles-active,polar and chiral-in asymmetric structures.However,the transport of deformable particles in asymmetric channel has not been examined relatively.Particles in soft material systems such as cell monolayer,tissue,foam,and emulsion are frequently deformable.The shape deformation of these soft particles significantly affects the system’s dynamic behavior.Thus,understanding the guided transport of these deformable particles within a confined structure is crucial.In order to explain this problem more clearly,we numerically simulate the guided transportation of active,deformable particles within a two-dimensional,periodic,asymmetric channel.We identify the factors that influence the transport of these particles within a confined structure.The main feature of the deformable particle model is that the particle’s shape is characterized by multiple degree of freedom.For active deformable particles,self-propulsion speed disrupts thermodynamic equilibrium,leading to guided transport in spatially asymmetric condition.Our findings demonstrate that a particle’s direction of movement is entirely determined by the channel's asymmetric parameter,and it tends to be attracted towards increased stability.Augmenting particle self-propulsion speed and particle softness can facilitate ratchet transport.When the self-propulsion speed v0 is large,the particle’s tensile effect becomes more apparent,and particle softening significantly enhances directed transport.In contrast,an increase in density and rotational diffusion can slow particle rectification.Increased density can obstruct particles,making channel passage more difficult.Elevated rotational diffusion reduces persistence length,challenging particle transition through channels.With constant density,a greater number of particles will also encourage rectification.These research findings offer a valuable insight into the transportation behaviors of deformable particles in a confined structure.They also deliver crucial theoretical support for applicable experiments in the field of soft matter.