Sigma models in the presence of dynamical point-like defects
  Point-like Liouville integrable dynamical defects are introduced in the context of the Landau-Lifshitz and Principal Chiral (Faddeev-Reshetikhin) models. Based primarily on the underlying quadratic algebra we identify the first local integrals of motion, the associated Lax pairs as well as the relevant sewing conditions around the defect point. The involution of the integrals of motion is shown taking into account the sewing conditions. 
Anastasia Doikou and Nikos Karaiskos
hep-th math-ph math.MP nlin.SI