3D van der Waals sigma-model and topological excitations with logarithmic energy
arXiv:hep-th/9909023
Abstract
The 3D vector van der Waals (or conformal) nonlinear sigma-model is proposed. It is shown that it has the "hedgehog"-like topological excitations with logarithmic energy. Their "neutral" configurations have nontrivial topological structures described by Hopf invariant. A possible influence of these excitations on the properties of the model are discussed.
14 pages, a talk given at seminar "Properties and Dynamics of Liquid Crystals", 23 August, MPIPKS, Dresden, Germany