Magnetization relaxation and geometric forces in a Bose ferromagnet.

Autor: Armaitis J; Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands. j.armaitis@uu.nl, Stoof HT, Duine RA
Jazyk: angličtina
Zdroj: Physical review letters [Phys Rev Lett] 2013 Jun 28; Vol. 110 (26), pp. 260404. Date of Electronic Publication: 2013 Jun 26.
DOI: 10.1103/PhysRevLett.110.260404
Abstrakt: We construct the hydrodynamic theory for spin-1/2 Bose gases at arbitrary temperatures. This theory describes the coupling between the magnetization and the normal and superfluid components of the gas. In particular, our theory contains the geometric forces on the particles that arise from their spin's adiabatic following of the magnetization texture. The phenomenological parameters of the hydrodynamic theory are calculated in the Bogoliubov approximation and using the Boltzmann equation in the relaxation-time approximation. We consider the topological Hall effect due to the presence of a Skyrmion, and show that this effect manifests itself in the collective modes of the system. The dissipative coupling between the magnetization and the normal component is shown to give rise to magnetization relaxation that is fourth order in spatial gradients of the magnetization direction.
Databáze: MEDLINE