About Two-Time Model and the Spatial Distribution of BEC Magnons
Abstract
Since the Bose-Einstein condensation (BEC) of magnons in ferromagnetic films was realized, it has drawn much attention due to the unique property of magnon spectrum. Namely, the BEC has two components corresponding to the two ground states of magnons. In recent years, experiments showed the repulsive nature of magnons and the spatial separation of condensate magnon cloud, contradicting the existing quasi-equilibrium theory. To explain such phenomena, we found the error in this theory: The equilibrium state of the two components is never reached, and, on the contrary, the flipping rate of magnon from one component into the other is much lower than its self-decay rate.
In the following part, we proposed the two-time model, treating magnons as classical particles. The model is based on the continuity equation of magnon creation, annihilation, and flow. With its help, we can not only explain the experimental findings, but also explore a fundamental question: the spatial distribution of BEC magnons.
Citation
Jia, Haichen (2021). About Two-Time Model and the Spatial Distribution of BEC Magnons. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /196031.