Compatibility of transport effects in non-Hermitian tight-binding models*

In this talk, we show conditions for effects such as reflectionless and transparent transport, lasing, and coherent perfect absorption in non-Hermitian topological model. We then identify which effects are compatible and linked with each other and determine by which levers they can be tuned independently.

For instance, we will show that the well-known non-Hermitian skin effect does not enter the spectral conditions for reflectionless transport, lasing, or coherent perfect absorption, but allows to adjust the transparency of the system. In addition, the conditions for reflectionless transport in the topological model depend on the topological phase, but those for coherent perfect absorption do not.

In our study, we investigate transport signatures of non-Hermitian, nonreciprocal, and topological behaviour, and derive new results such as (I) reflectionless transport in a direction that depends on the topological phase, (II) invisibility coinciding with the skin-effect phase transition of topological edge states,

and (III) coherent perfect absorption in a system that is transparent when probed from one side. Our study focuses on the non-Hermitian SSH model, but we show generalization to other topological systems.