Bose-Einstein condensation of magnons in superfluid 3He

Understand

The possibility of Bose-Einstein condensation of excitations has been discussed for a long time.

• The phenomenon of the phase-coherent precession of magnetization in superfluid 3He and the related effects of spin superfluidity are based on the true Bose-Einstein condensation of magnons.
• Several different states of coherent precession has been observed in 3He-B: homogeneously precessing domain (HPD); persistent signal formed by Q-balls at very low temperatures; coherent precession with fractional magnetization; and two new modes of the coherent precession in compressed aerogel.
• In compressed aerogel the coherent precession has been also found in 3He-A.