From exceptional field theory to heterotic double field theory via K3

Heterotic String Field Theory Yuji

We construct the Neveu-Schwarz sector of heterotic string field theory using the large Hilbert space of the superghosts and the multi-string products of bosonic closed string field theory. No picture-changing operators are required as in Wess-Zumino-Witten-like open superstring field theory. The action exhibits a novel kind of nonpolynomiality: in addition to terms necessary to cover missing re...

Loops in exceptional field theory

Heterotic conformal field theory and Gepner's construction.

Topics in Two-Dimensional Field Theory and Heterotic String Theory

We study a myriad of topics related to string theories in two dimensions and/or to heterotic string theories. In chapter 2, we use the duality of two-dimensional string theory with matrix models to study arbitrary time-dependent backgrounds. As an example, we study the case of a Fermi droplet cosmology and analyze properties of the coordinates in which the metric is trivial; we also comment on ...

From euclidean field theory to quantum field theory

In order to construct examples for interacting quantum field theory models, the methods of euclidean field theory have turned out to be a powerful tools since they make use of the techniques of classical statistical mechanics. Starting from an appropriate set of euclidean 3⁄4 -point functions (Schwinger distributions), a Wightman theory can be reconstructed by an application of the famous Oster...