  Magnets are interesting materials for classical and quantum information
technologies. However, the short decoherence and dephasing times that determine
the scale and speed of information networks, severely limit the appeal of
employing the ferromagnetic resonance. Here we show that the lifetime and
coherence of the uniform Kittel mode can be enhanced by 3-magnon
interaction-induced mixing with the long-lived magnons at the minima of the
dispersion relation. Analytical and numerical calculations based on this model
explain recent experimental results and predict experimental signatures of
quantum coherence.
