Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by applied fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems.

中文翻译：

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呼吸性烧绿石反铁磁体中的Weyl磁农。

沮丧的量子磁体不仅提供奇异的基态和异常的磁性结构，而且在许多情况下还支持非常规激发。使用物理相关的自旋模型为呼吸的烧绿石晶格，我们讨论了反铁磁体中磁振子的拓扑线性带交叉的存在。这些是电子系统中Weyl费米子的类似物，我们称其为Weyl磁振子。大量的Weyl磁振子意味着存在以有限能量形成电弧的手性磁振子表面态。我们认为这种反铁磁体是一个独特的例子，其中Weyl点可以在实验室中通过应用领域进行原位操作。我们专门讨论了它们在呼吸中的烧绿石晶格中的出现，并就寻找Weyl magnons的条件进行了一般性讨论，以及如何通过实验对其进行探测。