ﻻ يوجد ملخص باللغة العربية
In this work we analyze F-theory and Type IIB orientifold compactifications to study $alpha $-corrections to the four-dimensional, $mathcal{N} = 1$ effective actions. In particular, we obtain corrections to the Kahlermoduli space metric and its complex structure for generic dimension originating from eight-derivative corrections to eleven-dimensional supergravity. We propose a completion of the $G^ 2 R^3$ and $( abla G)^2R^2$-sector in eleven-dimensions relevant in Calabi--Yau fourfold reductions. We suggest that the three-dimensional, $mathcal{N}=2$ Kahler coordinates may be expressed as topological integrals depending on the first, second, and third Chern-forms of the divisors of the internal Calabi--Yau fourfold. The divisor integral Ansatz for the Kahler potential and Kahler coordinates may be lifted to four-dimensional, $mathcal{N} = 1$ F-theory vacua. We identify a novel correction to the Kahler potential and coordinates at order $ alpha^2$, which is leading compared to other known corrections in the literature. At weak string coupling the correction arises from the intersection of $D7$-branes and $O7$-planes with base divisors and the volume of self-intersection curves of divisors in the base. In the presence of the conjectured novel $alpha$-correction resulting from the divisor interpretation the no-scale structure may be broken. Furthermore, we propose a model independent scenario to achieve non-supersymmetric AdS vacua for Calabi-Yau orientifold backgrounds with negative Euler-characteristic.
We examine the vacuum structure of 4D effective theories of moduli fields in spacetime compactifications with quantized background fluxes. Imposing the no-scale structure for the volume deformations, we numerically investigate the distributions of fl
In this work we analyze the role of $alpha $-corrections to type IIB orientifold compactifications in Kahler moduli stabilization and inflation. In particular, we propose a model independent scenario to achieve non-supersymmetric Minkowski and de Sit
We study string loop corrections to the gravity kinetic terms in type IIB compactifications on Calabi-Yau threefolds or their orbifold limits, in the presence of $D7$-branes and orientifold planes. We show that they exhibit in general a logarithmic b
The Schwarzschild, Schwarzschild-AdS, and Schwarzschild-de Sitter solutions all admit freely acting discrete involutions which commute with the continuous symmetries of the spacetimes. Intuitively, these involutions correspond to the antipodal map of
In this paper we derive the tree-level S-matrix of the effective theory of Goldstone bosons known as the non-linear sigma model (NLSM) from string theory. This novel connection relies on a recent realization of tree-level open-superstring S-matrix pr