On String Vacua without Supersymmetry: brane dynamics, bubbles and holography

Understand

In this thesis we investigate some aspects of the dramatic consequences of supersymmetry breaking on string vacua.

• In particular, we focus on the issue of vacuum stability in ten-dimensional string models with broken, or without, supersymmetry, whose perturbative spectra are free of tachyons.
• After formulating the models at stake in Chapter 2, we introduce their low-energy effective description in Chapter 3, presenting a number of vacuum solutions to the classical equations of motion.
• In Chapter 4 we analyze their classical stability, studying linearized field fluctuations, and in Chapter 5 we turn to the issue of quantum stability.