论文标题
偶极链中的稳定且不稳定的轨迹
Stable and unstable trajectories in a dipolar chain
论文作者
论文摘要
在经典力学中,可以根据其稳定性对解决方案进行分类。它们都是系统可能轨迹的一部分。但是,在实验中很难观察到不稳定溶液的签名,并且在大多数情况下,如果实验实现是绝热的,则将它们视为一种滋扰。在这里,我们使用少数受外部磁场的XY磁性偶极子来研究其集体磁反应的起源。使用分叉理论,我们发现所有可能的解决方案都是稳定或不稳定的,并探讨了这些解决方案如何通过系统的对称性丢失或恢复的点自然连接。发现揭示系统对称性的不稳定解决方案被认为是塑造该系统中磁滞回路的罪魁祸首。使用边界盆地熵的概念分析了非线性动力学解决方案的复杂性,发现阻尼时间尺度对于吸引盆地中分形结构的出现至关重要。此外,我们从数值上找到了域壁溶液,这些域壁溶液是磁性中横向壁和涡旋壁的最小实现。我们通过实验证实了它们的存在和稳定性,这表明我们的系统是研究宏观上研究域壁动力学的合适平台。
In classical mechanics, solutions can be classified according to their stability. Each of them is part of the possible trajectories of the system. However, the signatures of unstable solutions are hard to observe in an experiment, and most of the times if the experimental realization is adiabatic, they are considered just a nuisance. Here we use a small number of XY magnetic dipoles subject to an external magnetic field for studying the origin of their collective magnetic response. Using bifurcation theory we have found all the possible solutions being stable or unstable, and explored how those solutions are naturally connected by points where the symmetries of the system are lost or restored. Unstable solutions that reveal the symmetries of the system are found to be the culprit that shape hysteresis loops in this system. The complexity of the solutions for the nonlinear dynamics is analyzed using the concept of boundary basin entropy, finding that the damping time scale is critical for the emergence of fractal structures in the basins of attraction. Furthermore, we numerically found domain wall solutions that are the smallest possible realizations of transverse walls and vortex walls in magnetism. We experimentally confirmed their existence and stability showing that our system is a suitable platform to study domain wall dynamics at the macroscale.