Gauge-dependent topology in non-reciprocal hopping systems with pseudo-Hermitian symmetry

Non-Hermitian physics, an active topic in photonics, is also being increasingly extended to investigate the band topologies of condensed-matter systems. Here, the authors report a 2D non-Hermitian model exhibiting exceptional rings and topological boundary modes in the spectral degeneracy, they propose how to realise these features using topolectrical circuits.