The scratched-XY model in 2D: it is not Kosterlitz-Thouless
Abstract: I show that the 2D classical XY model with disordered scratches can host a new mechanism to destroy superfluidity. As the disorder grows stronger the mechanism driving the superfluid transition changes from conventional vortex-pair unbinding (Kosterlitz-Thouless physics) to a strong randomness criticality characterized by a non-universal jump of the superfluid stiffness. The strong randomness criticality can be described by an asymptotically exact semi-renormalization group theory, previously developed for the superfluid-insulator transition in one-dimensional disordered quantum systems, whose physics I will review. Numerical simulation unambiguously establish that this theory indeed describes the physics of the classical 2D XY model with disordered scratches.
Contact: Lei Wang, 9853