Dynamical stability of the quantum Lifshitz theory in 2+1 Dimensions
  The role of magnetic and electric perturbations to the quantum Lifshitz model in 2+1 dimensions are examined in this paper. The quantum Lifshitz model is an effective field theory for quantum multicritical systems, that include generalized 2D quantum dimer models in bipartite lattices and their generalizations. It describes a class of quantum phase transitions between ordered and topological phases in 2+1 dimensions. Magnetic perturbations break the dimer conservation law. Electric excitations, whose condensation lead to ordered phases, have been studied extensively both in the classical 3D model and in the quantum 2D model. However, the role of magnetic vortex excitations whose condensation drive these systems into a $\mathbb{Z}_2$ topological phase has been largely ignored. To study the interplay of both excitations, we perform a perturbative renormalization group study to one loop order and study the stability of the theory away from quantum multi criticality. This is done by generalizing the operator product expansion to anisotropic models. The relation with recent classical Monte Carlo simulations in Rokhsar-Kivelson wave functions will be discussed. 
Benjamin Hsu and Eduardo Fradkin
cond-mat.str-el cond-mat.stat-mech