  In Hermitian systems, according to the bulk-edge correspondence interfacing
two topological optical media with different bulk topological numbers implies
the existence of edge states, which can trap light at the interface. However,
such a general scenario can be violated when dealing with non-Hermitian
systems. Here we show that interfacing two semi-infinite Hatano-Nelson chains
with different bulk topological numbers can result in the existence of
infinitely many edge (interface) states, however light waves cannot be rather
generally trapped at the interface.
