Topological transport control of colloidal particles

在这个实验/理论结合的项目中，我们的目标是理解和揭示拓扑在磁性软物质系统输运中的作用。拓扑学在电子系统中起着至关重要的作用，保护电荷和自旋的输运免受耗散散射的影响，而耗散散射在拓扑平凡的系统中通常会破坏输运。在拓扑非平凡电子系统中，在中能固体物理实验中发现了一大批原本在高能物理中假定的具有不同寻常输运性质的新粒子。这个领域足够大，可以招待固态社区十多年。在最近的工作中，我们已经证明，在软物质系统中可以发现类似的行为，尽管不完全相同，其中驱动磁性胶体或携带磁矩的自推进磁性细菌取代了电子，周期性磁性模式取代了背景固态。由于在这种情况下被输送的物体嵌入到粘性流体中，因此输送涉及到真正的耗散，这与固态系统中防止耗散的保护是一个主要区别。由于传输物体的介观尺寸，该系统可以用经典物理而不是量子物理来处理，这是与电子量子系统的第二个不太相关的区别。本提案的主要目的是进一步研究拓扑保护在软物质系统中的作用，通过实验和计算机模拟驱动磁性胶体复合物的输运和自推进趋磁细菌。拓扑控制应应用于胶体聚集体的家庭，每个家庭在不同的方向随意运输使用多语言控制回路。

In this combined experimental/theoretical project we aim to understand and unravel the role of topology in the transport of magnetic soft matter systems. Topology plays a crucial role in electronic systems protecting the transport of charge and spin against dissipative scattering which in topologically trivial systems usually destroys the transport. In topologically nontrivial electronic systems a whole zoo of new kind of particles originally postulated in high energy physics with unusual transport properties could be found experimentally in medium energy solid state physics. The field is large enough to entertain the solid-state community for more than a decade. In recent work we have shown that similar, albeit not identical, behaviour can be found in soft matter systems, where driven magnetic colloids or self-propelling magnetic bacteria carrying a magnetic moment replace the electrons and periodic magnetic patterns replace the background solid state. Since the transported objects in this case are embedded into a viscous fluid, the transport involves true dissipation which constitutes a major difference to the protection against dissipation in solid state systems. Due to the mesoscopic size of the transported objects the system can be treated by classical instead of quantum physics, which is a second, less relevant, difference to electronic quantum systems. The main purpose of this proposal is to further examine the role topological protection plays in soft matter systems performing both experiments and computer simulations on the transport of driven magnetic colloidal complexes and on self-propelled magnetotactic bacteria. The topological control shall be applied to families of colloidal aggregates, with each family being transported in a different direction at will using polyglot control loops.