Exceptional nexus with a hybrid topological invariant

doi:10.1126/science.abd8872

GSTDTAP > 气候变化

DOI	10.1126/science.abd8872
	Exceptional nexus with a hybrid topological invariant
	Weiyuan Tang; Xue Jiang; Kun Ding; Yi-Xin Xiao; Zhao-Qing Zhang; C. T. Chan; Guancong Ma
	2020-11-27
发表期刊	Science
出版年	2020
英文摘要	The exploration of non-Hermitian physics and parity-time symmetry have provided a route to develop a wealth of exotic physical effects. In such dissipative systems, the balance of gain and loss of the system lead to what are called exceptional points, or “sweet spots,” which relate to optimal device operation or material properties. The ability to tune the gain and loss over a range of system properties leads to exceptional arcs. Tang et al. show that systems can be designed in which the tuning of multiple parameters leads to a crossroads, or nexus, of exceptional arcs. Illustrating the effect in an acoustic system, the same properties should be attainable over various types of dissipative systems and thus provide a versatile route to fine-tune optimal performance of materials and devices. Science , this issue p. [1077][1] Branch-point singularities known as exceptional points (EPs), which carry a nonzero topological charge, can emerge in non-Hermitian systems. We demonstrate with both theory and acoustic experiments an “exceptional nexus” (EX), which is not only a higher-order EP but also the cusp singularity of multiple exceptional arcs (EAs). Because the parameter space is segmented by the EAs, the EX possesses a hybrid topological invariant (HTI), which consists of distinct winding numbers associated with Berry phases accumulated by cyclic paths on different complex planes. The HTI is experimentally characterized by measuring the critical behaviors of the wave functions. Our findings constitute a major advance in the fundamental understanding of non-Hermitian systems and their topology, possibly opening new avenues for applications. [1]: /lookup/doi/10.1126/science.abd8872
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/304881
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Weiyuan Tang,Xue Jiang,Kun Ding,et al. Exceptional nexus with a hybrid topological invariant[J]. Science,2020.
APA	Weiyuan Tang.,Xue Jiang.,Kun Ding.,Yi-Xin Xiao.,Zhao-Qing Zhang.,...&Guancong Ma.(2020).Exceptional nexus with a hybrid topological invariant.Science.
MLA	Weiyuan Tang,et al."Exceptional nexus with a hybrid topological invariant".Science (2020).