# Realistic Ground States of String Theory

The Swedish Research Council reached a decision on February 23, 2017 on project grants and starting grants on Natural and Engineering Sciences. The Department of Physics and Astronomy is granted 45.9 million SEK for the period 2016-2020 for in total six project grants and six starting grants. The projects will begin during 2017.

## Project description

Magdalena Larfors, Theoretical Physics, was granted 3.6 million SEK for the project *“**Realistic Ground States of String Theory”* from the Swedish Research Council for the period 2016-2020.

### Project description

This project addresses one of the most important aspects of string theory: how stable and realistic ground states can be constructed. Compactified string theory solutions can successfully model fundamental features of particle physics or cosmology, but fully realistic vacua are lacking. The physics of these constructions is determined by an internal, compact geometry. Traditional string vacua use Calabi-Yau spaces, that are mathematically well-understood. However, these geometries have parameters which lead to massless scalar particles in contradiction with observations.

The aim of this project is to construct non-CY spaces of interest for compactifications of heterotic string theory, and to explore the mathematical and physical properties of these constructions. Novel methods based on algebraic geometry, generalised geometry, and double field theory will be drawn upon to meet this goal. When combined with string dualities and the constraints from supersymmetry, this allows an efficient analysis and promises rapid progress. The resulting four-dimensional models will be studied in detail, and scans for models with realistic particle physics and cosmological properties will be undertaken.