Magnetic domain growth in a ferromagnetic Bose-Einstein condensate: Effects of current

Magnetic domain patterns in a ferromagnetic Bose-Einstein condensate (BEC) show different properties depending on the quadratic Zeeman effect and dissipation. Another important factor that affects domain patterns and domain growth is superfluid flow of atoms. Domain growth in a ferromagnetic BEC with negative quadratic Zeeman energy is characterized by the same growth law as a (classical) binary fluid in the inertial hydrodynamic regime. In the absence of the superfluid flow, the domain growth law for negative quadratic Zeeman energy is the same as that of scalar conserved fields, such as binary alloys.

Figure 1

Time dependences of the spatial average of transverse magnetization $|F_{+}|$, that of magnetization rate $\left|\mathit{f}\right|/n_{\mathrm{tot}}$, and that of longitudinal magnetization $|f_z|/n_{\mathrm{tot}}$ in the GP simulations. Each curve is the ensemble average of five simulations.

Figure 2

Time dependence of domain size $l\left(t\right)$ in the GP simulations. Each curve is the ensemble average of five simulations.

Figure 3

Snapshots of longitudinal magnetization $f_z/n_{\mathrm{tot}}$ obtained by the GP simulations. The size of each snapshot is 300 $\mu$m on each side.

Figure 4

Time dependence of domain size $l\left(t\right)$ obtained by the hydrodynamic simulations (a) with ${\mathit{v}}_{\mathrm{mass}}$ and (b) without ${\mathit{v}}_{\mathrm{mass}}$. Each curve is the ensemble average of five simulations.

Figure 5

Time dependences of the spatial average of transverse magnetization $|F_{+}|$ in (a) fully hydrodynamic and (b) no-${\mathit{v}}_{\mathrm{mass}}$ simulations. Each curve is the ensemble average of five simulations.

Figure 6

Snapshots of longitudinal magnetization ${\widehat{f}}_z$ in (a) fully hydrodynamic and (b) no-${\mathit{v}}_{\mathrm{mass}}$ simulations. The size of each snapshot is 300 $\mu$m on each side.