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

We perform some systematic numerical search for Schwinger boson mean field states on square and triangular lattice 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.