Distributed topological zero modes in a Non Hermitian quantum system

Non-Hermitian systems have emerged recently due to their unique properties, like

faster propagation of wave packets in contrast to Hermitian counterparts, non-reciprocal

wave guiding, etc. In general, non-reciprocity can be tailored through unequal directional

hopping between two different sites and also via onsite gain/loss balancing. The goal of this

research is to examine the impact of both non-hermitian constitutive parameters, i.e

directionality and gain/loss, in a coupled one-dimensional (1D) double-chain network. The

directional hopping in a 1D system causes the localization of bulk modes at the boundaries,

known as non-Hermitian skin effect (NHSE), whereas the precise tuning of the gain/loss

parameters leads to a complete delocalization of zero modes connecting NHSE at the two

ends. This transition of zero modes from localised to delocalized state is well protected by

bulk topology and also characterized through a change in topological invariant.

Finally, a one-way invisible complete transmission phenomenon has been demonstrated

across this network using wavepacket tunnelling.