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Dynamics of a Bose-Einstein Condensate of Excited Magnons
The emergence of a non-equilibrium Bose-Einstein-like condensation of magnons
in rf-pumped magnetic thin films has recently been experimentally observed. We
present here a complete theoretical description of the non-equilibrium
processes involved. It it demonstrated that the phenomenon is another example
of the presence of a Bose-Einstein-like condensation in non-equilibrium
many-boson systems embedded in a thermal bath, better referred-to as
Fr\"{o}hlich-Bose-Einstein condensation. The complex behavior emerges after a
threshold of the exciting intensity is attained. It is inhibited at higher
intensities when the magnon-magnon interaction drives the magnons to internal
thermalization. The observed behavior of the relaxation to equilibrium after
the end of the pumping pulse is also accounted for and the different processes
fully described.Comment: 42 pages, 11 figure
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