  We present a simple quantum theory of a bosonic trimer in a triangular
configuration, subject to gain and loss in an open quantum systems approach.
Importantly, the coupling constants between each oscillator are augmented by
complex arguments, which give rise to various asymmetries. In particular, one
may tune the complex phases to induce chiral currents, including the special
case of completely unidirectional (or one-way) circulation when certain
conditions are met regarding the coherent and incoherent couplings. When our
general theory is recast into a specific non-Hermitian Hamiltonian, we find
interesting features in the trimer population dynamics close to the exceptional
points between phases of broken and unbroken $\mathcal{PT}$ symmetry. Our
theoretical work provides perspectives for the experimental realization of
chiral transport at the nanoscale in a variety of accessible nanophotonic and
nanoplasmonic systems, and paves the way for the potential actualization of
nonreciprocal devices.
