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Moduli Stabilisation for Chiral Global Models
 JHEP 1202 (2012) 062, arXiv:1110.3333 [hepth
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Toric K3Fibred CalabiYau Manifolds with del Pezzo Divisors for String Compactifications
 JHEP 1202 (2012) 002, ARXIV:1107.0383 [HEPTH
, 2012
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Global Ftheory GUTs
, 908
"... We construct global Ftheory GUT models on del Pezzo surfaces in compact CalabiYau fourfolds realized as complete intersections of two hypersurface constraints. The intersections of the GUT brane and the flavour branes as well as the gauge flux are described by the spectral cover construction. We c ..."
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We construct global Ftheory GUT models on del Pezzo surfaces in compact CalabiYau fourfolds realized as complete intersections of two hypersurface constraints. The intersections of the GUT brane and the flavour branes as well as the gauge flux are described by the spectral cover construction. We consider a split S[U(4)×U(1)X] spectral cover, which allows for the phenomenologically relevant Yukawa couplings and GUT breaking to the MSSM via hypercharge flux while preventing dimension4 proton decay. General expressions for the massless spectrum, consistency conditions and a new method for the computation of curvatureinduced tadpoles are presented. We also provide a geometric toolkit for further model searches in the framework of toric geometry. Finally, an explicit global model with three chiral generations and all required Yukawa couplings is defined on a CalabiYau fourfold which is fibered over the del Pezzo transition of the Fano threefold P 4 [4].
Ftheory Yukawa Couplings and Supersymmetric Quantum Mechanics,” Nucl
 Oikonomou, “Ftheory and the Witten Index,” Nucl. Phys. B 850
, 2011
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Building an explicit de Sitter
 PREPARED FOR SUBMISSION TO JHEP
, 2012
"... We construct an explicit example of a de Sitter vacuum in type IIB string theory that realizes the proposal of Kähler uplifting. As the large volume limit in this method depends on the rank of the largest condensing gauge group we carry out a scan of gauge group ranks over the KreuzerSkarke set o ..."
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Cited by 2 (0 self)
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We construct an explicit example of a de Sitter vacuum in type IIB string theory that realizes the proposal of Kähler uplifting. As the large volume limit in this method depends on the rank of the largest condensing gauge group we carry out a scan of gauge group ranks over the KreuzerSkarke set of toric CalabiYau threefolds. We find large numbers of models with the largest gauge group factor easily exceeding a rank of one hundred. We construct a global model with Kähler uplifting on a twoparameter model on CP411169, by an explicit analysis from both the type IIB and Ftheory point of view. The explicitness of the construction lies in the realization of a D7 brane configuration, gauge flux and RR and NS flux choices, such that all known consistency conditions are met and the geometric moduli are stabilized in a metastable de Sitter vacuum with spontaneous GUT scale supersymmetry breaking driven by an Fterm of the Kähler moduli.
Tate Form and Weak Coupling Limits in Ftheory
"... We consider the weak coupling limit of Ftheory in the presence of nonAbelian gauge groups implemented using the traditional ansatz coming from Tate’s algorithm. We classify the types of singularities that could appear in the weak coupling limit and explain their resolution. In particular, the weak ..."
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We consider the weak coupling limit of Ftheory in the presence of nonAbelian gauge groups implemented using the traditional ansatz coming from Tate’s algorithm. We classify the types of singularities that could appear in the weak coupling limit and explain their resolution. In particular, the weak coupling limit of SU(n) gauge groups leads to an orientifold theory which suffers from conifold singulaties that do not admit a crepant resolution compatible with the orientifold involution. We present a simple resolution to this problem by introducing a new weak coupling regime that admits singularities compatible with both a crepant resolution and an orientifold symmetry. We also comment on possible applications of the new limit to model building. We finally discuss other unexpected phenomena as for example the existence of several nonequivalent directions to flow from strong to weak coupling leading to different gauge groups. ♠Email: esole at math.harvard.edu ♦Email: savelli at mpp.mpg.de ar X iv
Gauge Fluxes in Ftheory and Type IIB Orientifolds
"... We provide a detailed correspondence between G4 gauge fluxes in Ftheory compactifications with SU(n) and SU(n) × U(1) gauge symmetry and their Type IIB orientifold limit. Based on the resolution of the relevant Ftheory Tate models we classify the factorisable G4fluxes and match them with the se ..."
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We provide a detailed correspondence between G4 gauge fluxes in Ftheory compactifications with SU(n) and SU(n) × U(1) gauge symmetry and their Type IIB orientifold limit. Based on the resolution of the relevant Ftheory Tate models we classify the factorisable G4fluxes and match them with the set of universal D5tadpole free U(1)fluxes in Type IIB. Where available, the global version of the universal spectral cover flux corresponds to Type IIB gauge flux associated with a massive diagonal U(1). In U(1)restricted Tate models extra massless abelian fluxes exist which are associated with specific linear combinations of Type IIB fluxes. Key to a quantitative match between Ftheory and Type IIB is a proper treatment of the conifold singularity encountered in the Sen limit of generic Ftheory models. We also collect evidence that the Type IIB orientifold limit of the considered Tate models involves a nontrivial Bfield and shed further light on the brane recombination process relating generic and U(1)restricted Tate models. ar X iv