  The quantized conductance plateaus and zero conductance fluctuation are the
general consequence of electron transport in chiral edge states of Hermitian
Chern insulators. Here we show that the physics of electron transport through
chiral or helical edge channels becomes much richer when the non-Hermicity is
allowed. In the presence of an unbalanced non-Hermicity where the chiral edge
states have finite-lifetime, the conductance of the edge channels is not
quantized, but its conductance fluctuation is zero. For the balanced
non-Hermicity, however, the chiral edge states have infinite-lifetime, and the
conductance is quantized as in the case of Hermitian Chern insulators. Both
non-quantized and quantized conductance plateaus of zero conductance
fluctuation are robust against disorders. We present a theory that explains the
origin of the non-quantized conductance plateaus. The physics revealed here
should also be true for the chiral and helical surface states in other
topological materials such as quantum anomalous Hall systems, Weyl semimetals,
and topological superconductors.
