Falk Hassler
Postdoc at the Mitchell Institute for Fundamental Physics and Astronomy
I am currently a postdoctoral researcher at the Mitchel Institution for Fundamental Physics and Astronomy at Texas A&M University. Before coming here, I was a postdoc at the University of Oviedo for one year and at UNC Chapel Hill for three year. But this does not mean that I have been in Chapel Hill all the time. Over the last years I was moving every year due to some funny coincidences. After my time as a PhD student at LMU Munich under the supervision of Dieter Lüst, I spend one year in New York as a visiting researcher at the CUNY Graduate Center and Columbia. After that, it was planned to go for two years to Chapel Hill. However, Jonathan Heckman, who hired me at UNC, accepted an offer from UPenn. So I only spend one year in Chapel Hill and moved for a another year to Philadelphia before coming to Yolanda Lozano's group in Oviedo for my second postdoc.

## 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.