  Dissipation is a common occurrence in real-world systems and is generally
considered to be detrimental to transport. In this study, we examine the
transport properties of a narrow quantum anomalous Hall system with dissipation
applied on one edge. When the Fermi level resides within the hybridization gap,
we find that while transport is suppressed on one edge, it is significantly
enhanced on the other. We reveal that this enhancement arises from
dissipation-induced gap closure, which is deeply rooted in the point gap
topology of the system, resulting in a reduction of the decaying coefficient.
When the dissipation is very large, we find that the low-energy physics is
nearly indistinguishable from a narrower system, whose dissipation amplitude is
inversely proportional to that of the original one. To get more physical
intuition, we demonstrate that the low-energy physics can be well captured by a
pair of coupled counter-propagating chiral edge states, one of which has a
modified group velocity and an effective dissipation. We also briefly discuss
the possible experimental realizations of this enhanced unidirectional
transport.
