Topological transport control of colloidal particles

在这个实验和理论相结合的项目中，我们的目标是理解和揭示拓扑学在磁性软物质系统输运中的作用。拓扑在电子系统中起着至关重要的作用，它保护电荷和自旋的输运不受耗散散射的影响，而在拓扑平凡的系统中，耗散散射通常会破坏输运。在拓扑学上非平凡的电子系统中，在中能固体物理中可以实验地发现一大群原本在高能物理中假定具有不寻常输运性质的新型粒子。这个领域足够大，足以让固态社区娱乐十多年。在最近的工作中，我们证明了类似的行为，尽管不完全相同，但在软物质系统中也可以发现类似的行为，其中驱动的磁性胶体或携带磁矩的自推进磁性细菌取代电子，周期性的磁图案取代背景固态。由于在这种情况下被传输的物体被嵌入到粘性流体中，因此传输涉及真正的耗散，这构成了固态系统中防耗散保护的主要区别。由于被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，这是第二个与电子量子系统不太相关的区别。这一提议的主要目的是进一步审查拓扑保护在软物质系统中所起的作用，该系统对驱动的磁性胶体络合物的传输和对自行式趋磁细菌进行实验和计算机模拟。拓扑控制应应用于胶体集合体家族，每个家族使用多语种控制回路以不同的方向随意运输。

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.