Falk Hassler
Postdoc at UNC Chapel Hill / UPenn
I am currently a postdoctoral researcher at the University of North Carolina at Chapel Hill, visiting the University of Pennsylvania for the academic year 2017/2018.

## Research interests

By using dualities in string theory, I explore quantum field theory and quantum gravity at strong coupling, very high energies and small distances. My current focus lies on double/exceptional field theory, an effective target space description of string/M-theory, which makes T-/U-duality manifest, and (super)conformal field theories, (S)CFTs, in two and more dimensions. On the formal side, I look into the underlying principles of generalized geometry, non-commutative or even non-associative geometry; especially, how they naturally arise from strings and higher dimensional membranes probing spacetime. String field theory, which allows to extract a lot of amazing mathematical structure from the string's worldsheet CFT, is a powerful tool in this realm. Although this is still a perturbative approach, it can point out underlying symmetry principles which allow to access the non-perturbative regime too. A very prominent example is supersymmetry which intriguingly allows to study certain protected sectors of a theory (like BPS solutions) at strong coupling. These special sectors are also an indispensable tool to study higher dimensional SCFTs which sometimes even do not have a weak coupling limit. Having all these fundamental aspects in mind, I am interested in concrete applications of them, too. They range from flux compactifications, over consistent truncations to simple toy models for inflation in cosmology. Recently, I explored the connection between double field theory and Poisson-Lie T-duality. This is very exciting, because the latter is closely related to integrable deformations of two dimensional $\sigma$-models. Such deformations are extensively studied in connection with the AdS/CFT correspondence. They exhibit the rich mathematical structure of quantum groups.