Anomalous Topology in Strongly Amorphous Networks

Topological phases of matters redefine the classification of crystals and provide wave control possibilities with unprecedented protection against obstacles, defects and local disorder. However, non-trivial topology inevitably collapses in the presence of strong structural disorder, as in amorphous systems, ultimately undergoing Anderson localization transition. Here, we demonstrate the possibility to obtain an amorphous anomalous topological phase that exists under any level of amorphism [1]. By exploiting a non-atomic limit in oriented scattering graphs, we construct a non-reciprocal scattering network that can enter an anomalous topological phase immune to arbitrary structural disorder and enhanced by strong amorphism. By building electromagnetic networks operating in the GHz range, we experimentally study the topological edge transport in strongly amorphous networks, and confirm the non-trivial topology by direct measurements of a topological scattering invariant.