Colloquium talks

Below is a selection of colloquium-style talks I have given on my research work.

  • Exceptional Field Theory and applications to the AdS/CFT correspondenceView slides
    Target audience: researchers working on QFT.
    Abstract: The AdS/CFT correspondence is a powerful tool for studying strongly coupled QFTs by performing computations in string theory and its low energy limit, supergravity. I will review Exceptional Field Theory, a formalism that unifies gravitational and flux degrees of freedom of supergravity, and thereby makes a large exceptional symmetry group manifest. This large symmetry group simplifies many complicated calculations in AdS backgrounds, such as constructing consistent truncations or computing the spectrum of linearised fluctuations around AdS vacua. I will show how this can be used to gain insights into strongly coupled QFTs. Finally, it time permits, I will discuss applications to non-supersymmetric AdS vacua.
  • Listening to the shape of string theory's extra dimensionsView slides
    Target audience: general physics audience.
    Abstract: All applications of string theory, whether in modelling fundamental particle physics interactions or in studying strongly-coupled quantum field theories via holography, require some of string theory's 10 dimensions to be "compactified", i.e. curled up into a small space. The shape of these compactified dimensions determines the physics, such as the spectrum of particles, observed in the remaining large dimensions. This is analogous to how the shape of instruments determines the sound of notes played. However, in practice, computing the spectrum for realistic compactifications reduces to a fiendishly complicated exercise in harmonic analysis. I will present new methods of performing this analysis and what this teaches us about the physics of string theory.

Research talks

Below is a selection of talks I have given on my research work.

Non-specialist talks

I have also given talks on my work to non-specialist audiences:

  • String theory, compactifications and our universe (in German), a talk given at the Bruno H. Bürgel astronomical observatory Berlin in February 2020.
    German title: Stringtheorie, Kompaktifizierungen und unser Universum
    Abstract (in German): Was passierte in dem Big Bang, den Urprunsgsmoments unseres Universums, als alle Materie in einem winzigen Ort zusammengedrückt war? Was geschieht tief im Inneren von Schwarzen Löchern? Um diese Fragen zu beantworten, brauchen wir eine Theorie der Quantengravitation. Unsere am besten entwickelte Quantengravitationstheorie ist die Stringtheorie, in der alle Elementarteilchen aus winzigen vibrierenden Saiten (Strings) bestehen. Eine Vorhersage der Stringtheorie ist, dass unser Universum weitere 6 Dimensionen hat, die in einen kleinen Raum gekrümmt sind. Die Form dieser "Kompaktifizierungen" bestimmt die Physik, z.B. die Arten an Elementarteilchen und elementaren Kräfte, die wir in einem Stringtheorie Universum erleben würden. In diesem Vortrag werde ich diese Beziehung zwischen Physik und der Form der gekrümmten Dimensionen erläutern, und neue Bestrebungen präsentieren, um die Stringtheorie experimentell zu testen.
  • String Theory and Double Field Theory: Why small circles and big circles are the same, a talk given at the Peterhouse Graduate Symposium in November 2013.
    Abstract: In everyday life, we think we understand the concept of size and that "small" and "big" are easily distinguishable. I will show why in string theory small and big circles are the same thing, why this gives string theory interesting properties and why we should care in the real world. I will then describe my research in double field theory and show how this naturally describes string theory by treating small and big circles in the same way.