ENERGY VERSUS TOPOLOGY - COMPETING DEFECT STRUCTURES IN 2D COMPLEX VECTOR FIELD

The topology of minimal orbits of the energy functional of a complex 2D vector field depends on the sign of nonlinear terms breaking the SU(2) symmetry, giving rise to either linearly or circularly polarized states (LP and CP) which possess different sets of defects. The CP vortices have two alternative core structures, with either vanishing amplitude or reversed polarization in the inner core. In the LP state, there are two distinct topological charges. Vortices carrying two half-unit charges have a circularly polarized core. Unit-charged vortices have a core with a vanishing amplitude, and may suffer a core instability splitting into a pair of half-unit-charged vortices.