  Chiral coupling at the single-quantum level promises to be a remarkable
potential for quantum information processing. Here we propose to achieve a
chiral interaction between a magnon mode in a ferromagnetic sphere and a
superconducting qubit mediated by a one-dimensional coupled-cavity array. When
the qubit is coupled to two lattice sites of the array and each one is encoded
with a tunable phase, we can acquire a directional qubit-magnon interaction via
the quantum interference effect. This work opens up a new route to construct
chiral devices, which are expected to become a building block in quantum
magnonic networks.
