Scheibner Colin, Irvine William T M, Vitelli Vincenzo
James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA.
Phys Rev Lett. 2020 Sep 11;125(11):118001. doi: 10.1103/PhysRevLett.125.118001.
Solids built out of active components can exhibit nonreciprocal elastic coefficients that give rise to non-Hermitian wave phenomena. Here, we investigate non-Hermitian effects present at the boundary of two-dimensional active elastic media obeying two general assumptions: their microscopic forces conserve linear momentum and arise only from static deformations. Using continuum equations, we demonstrate the existence of the non-Hermitian skin effect in which the boundary hosts an extensive number of localized modes. Furthermore, lattice models reveal non-Hermitian topological transitions mediated by exceptional rings driven by the activity level of individual bonds.
由活性组件构成的固体可以表现出非互易弹性系数，从而产生非厄米波动现象。在此，我们研究二维活性弹性介质边界处存在的非厄米效应，该介质遵循两个一般假设：其微观力守恒线性动量且仅由静态变形产生。使用连续介质方程，我们证明了非厄米趋肤效应的存在，其中边界处存在大量局域模式。此外，晶格模型揭示了由单个键的活性水平驱动的例外环介导的非厄米拓扑转变。
