Recently two groups of researchers [1], [2] presented experimental data in favor of superfluidity in the Bose-Einstein condensate of magnon liquid supported by permanent rf pumping at room temperature. We discuss these experiments. A basic component of theoretical approach is repulsive interaction between condensate magnons induced in the homogeneous stationary condensate state by the rf pumping. We construct simplified and complete theory of such system based on modified Gross-Pitaevskii equation. We discuss the experiment [2] that first displayed the strong repulsion of condensate magnons in an artificially created potential well. We also describe a new phenomenon found in experiment [2]: gigantic condensate response to a weak inhomogeneous magnetic field. Its theoretical explanation is proposed.
References:
[1] D.A. Bozhko et al., Nat. Phys. 12, 1057 (2015).
[2] I. Borisenko et al., Nat. Comm, in press. (2019).