Related papers: The String Landscape: On Formulas for Counting Vac…
In the recent times a lot of effort has been devoted to improve our knowledge about the space of string theory vacua (``the landscape'') to find statistical grounds to justify how and why the theory selects its vacuum. Particularly…
We present an exact description of the metric on the moduli space of vacua and the spectrum of massive states for four dimensional N=2 supersymmetric SU(n) gauge theories. The moduli space of quantum vacua is identified with the moduli…
Just comparing with the scenario that the (3+1)-dimensional "real world" of the Calabi-Yau compactification has a tremendous landscape, we conjecture that a (4+1)-dimensional holographic theory may also hold a landscape of its vacua. Unlike…
We search for $N=2$, $d=4$ theories which can be realized both as heterotic string compactifications on $K_{3}\times T^{2}$ and as type II string compactifications on Calabi-Yau threefolds. In such cases, the exact non-perturbative…
Heterotic vacua of string theory are realised, at large radius, by a compact threefold with vanishing first Chern class together with a choice of stable holomorphic vector bundle. These form a wide class of potentially realistic…
We study type IIA string theory compactified on Calabi-Yau fourfolds and heterotic string theory compactified on Calabi-Yau threefolds times a two-torus. We derive the resulting effective theories which have two space-time dimensions and…
The classification method of the free fermionic heterotic string vacua is extended to models where the $SO(10)$ GUT symmetry is broken directly at the string scale to the Left-Right Symmetric subgroup. Our method involves using a fixed set…
By reinterpreting the familiar tools and ideas of M-theory model building, we show how a G2-manifold locally engineered to give rise to massless matter representations of an SU(5) grand unified model can be smoothly unfolded into a…
Understanding supersymmetric flux vacua is essential in order to connect string theory to observable physics. In this thesis, flux vacua are studied by making use of two mathematical frameworks: SU(n)-structures and generalised complex…
Supersymmetric flux compactification of F-theory in the geometric phase yields numerous vacua, and provides an ensemble of low-energy effective theories with different symmetry, matter multiplicity and Lagrangian parameters. Theoretical…
The target space theory of the N=(2,1) heterotic string may be interpreted as a theory of gravity coupled to matter in either $1+1$ or $2+1$ dimensions. Among the target space theories in $1+1$ dimensions are the bosonic, type II, and…
We review the duality between heterotic and F--theory string vacua with N=1 space-time supersymmetry in eight, six and four dimensions. In particular, we discuss two chains of four-dimensional F--theory/heterotic dual string pairs, where…
A while ago, examples of N=1 vacua in D=6 were constructed as orientifolds of Type IIB string theory compactified on the K3 surface. Among the interesting features of those models was the presence of D5-branes behaving like small…
We examine some novel physical consequences of the general structure of moduli spaces of string vacua. These include (1) finiteness of the volume of the moduli space and (2) chaotic motion of the moduli in the early universe. To fix ideas…
We consider the relationship between the higher symmetry and the dynamical decomposition in supersymmetric gauge theory in various dimensions by studying the semi-classical potential energy. We observe that besides the scalar moduli we…
We employ powerful techniques based on Hilbert- and Groebner bases to analyze particle physics models derived from string theory. Individual models are shown to have a huge landscape of vacua that differ in their phenomenological…
In this Thesis we investigate properties of stability, rigidity and unitarity of the string landscape in ten and lower dimensions. The dissertation explores these aspects by intertwining a detailed analysis of string vacua, with and without…
We show that there exists an exponentially large discretuum of vacua in $G_2$-compactifications of M-theory without flux. In M-theory-inspired $G_2$-MSSM, quantities relevant for particle physics remain virtually insensitive to large…
Flux compactifications of $M$ theory on certain $G_2$-manifolds have vacua in which all moduli are determined.These vacua have discrete parameters - the flux quanta. Small changes in these quanta produce small changes in the moduli and…
We show that a large class of phenomenologically viable models for gauge mediation of supersymmetry breaking based on meta-stable vacua can be realized in local Calabi-Yau compactifications of string theory.