Relatore:  Antonino Flachi (Keio University, Tokyo)

Abstract: 

In this talk I will report an analysis of an interacting quantum field theory on a curved two-dimensional manifold constructed by geometrically deforming a flat hexagonal lattice by the insertion of a defect and taking subsequently the continuum limit. Depending on how the deformation is done, the resulting geometry acquires a locally non-vanishing curvature that can be either positive or negative. Fields propagating on this background are forced to satisfy boundary conditions modulated by the geometry and that can be assimilated by a non-dynamical gauge field. I will present an explicit example where curvature and boundary conditions compete in altering the way symmetry breaking takes place, resulting in a surprising behaviour of the order parameter in the vicinity of the defect. The effect described here is expected to be generic and of relevance in a variety of situations.