Generalised T-duality as a topological defect

Topological defects have long been known to encode symmetries and dualities between physical systems. In the context of string theory, defects have been intensively studied at the level of the worldsheet but hardly at the level of the target space. In this talk, I will show that a generalised notion of T-duality, dubbed Poisson-Lie T-duality, can be encoded as a topological defect at the level of the target space. This allows for a new perspective on this generalised duality and as a byproduct offers an alternative approach for studying the effect of the duality on D-branes and the RR-sector.