  Non-Hermitian systems have recently attracted broad interest and exhibited
intriguing physical phenomena, in which the non-Hermitian skin effect is one of
the most remarkable quantum phenomena desiring detailed investigations and has
been widely studied in various fermionic and bosonic systems. Here we propose a
non-Hermitian atom-waveguide system composed of a tilted one-dimensional atomic
array coupled with two identical waveguides with opposite chiralities. Such
system creates an effective lattice model including nonreciprocal long-range
hoppings through the chiral-waveguide photon-mediated interactions. We find the
excitation of the collective atomic states concentrates in the middle
interface, pointing towards the non-Hermitian skin effect associated with
subradiant modes, while, on the contrary, superradiant modes exhibit extended
features. Simulation results present subradiant funneling effect, with
robustness against small atomic position disorders. Our work underpins the
fundamental comprehension towards the non-Hermitian skin effect in open quantum
systems and also provide prospective paths to study non-Hermitian systems in
the area of quantum optics.
