1207.4058 (Grégoire Misguich)

Schwinger boson mean field theory: numerics for the energy landscape and
gauge excitations in two-dimensional antiferromagnets    [PDF]

Grégoire Misguich

We perform some systematic numerical search for Schwinger boson mean field states on the square, triangular and kagome clusters. We look for possible inhomogeneous ground states as well as low-energy excited saddle points. The spectrum of the Hessian is also computed for each solution. On the square lattice we find gapless U(1) gauge modes in the non-magnetic phase. In the Z_2 liquid phase of the triangular lattice we identify the topological degeneracy as well as vison states. The energy landscape on kagome lattices shows tiny energy scales and we discuss its relation to classical planar states.

View original: http://arxiv.org/abs/1207.4058