Theory HEP Seminar

Topological defects and generalised orbifolds

Nils Carqueville

Simons Center, Stony Brook

Ordinary orbifolds of finite symmetry groups in two-dimensional quantum field theories can be understood in terms of topological line defects. This point of view affords a natural extension, leading to new “generalised orbifold equivalences” which do not have to come from classical symmetries. I shall explain the basic ideas behind this general construction (naturally formulated in the setting of bicategories), discuss the relation to supersymmetry and fully extended TQFT, and give examples in the case of Landau-Ginzburg models.