Chiral Superradiance Magnon Laser

We propose a superradiant magnon laser based on an ensemble of nitrogen-vacancy (NV) centers positioned along a one-dimensional (1D) chain and coupled by magnetic dipolar interaction to a thin ferromagnetic strip. The coupling is chiral: NVs placed on one side of the strip emit magnons only into a single propagation direction. After a traveling-wave gauge, the coupling becomes uniform in phase and the atom-field dynamics reduces effectively to a single-mode Tavis-Cummings (TC) model in the bad-cavity regime. We derive the threshold, saturation, and linewidth in direct analogy with the optical superradiant-laser theory.