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48
Fourdimensional String Compactifications with DBranes, Orientifolds and Fluxes
"... This review article provides a pedagogical introduction into various classes of chiral string compactifications to four dimensions with Dbranes and fluxes. The main concern is to provide all necessary technical tools to explicitly construct fourdimensional orientifold vacua, with the final aim to ..."
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Cited by 147 (18 self)
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This review article provides a pedagogical introduction into various classes of chiral string compactifications to four dimensions with Dbranes and fluxes. The main concern is to provide all necessary technical tools to explicitly construct fourdimensional orientifold vacua, with the final aim to come as close as possible to the supersymmetric Standard Model. Furthermore, we outline the available methods to derive the resulting fourdimensional effective action. Finally, we summarize recent attempts to address the
Loopcorrected compactifications of the heterotic string with line bundles
, 2005
"... We consider the E8×E8 heterotic string theory compactified on CalabiYau manifolds with bundles containing abelian factors in their structure group. Generic low energy consequences such as the generalised GreenSchwarz mechanism for the multiple anomalous abelian gauge groups are studied. We also co ..."
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Cited by 84 (16 self)
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We consider the E8×E8 heterotic string theory compactified on CalabiYau manifolds with bundles containing abelian factors in their structure group. Generic low energy consequences such as the generalised GreenSchwarz mechanism for the multiple anomalous abelian gauge groups are studied. We also compute the holomorphic gauge couplings and induced FayetIliopoulos terms up to oneloop order, where the latter are interpreted as stringy oneloop corrections to the DonaldsonUhlenbeckYau condition. Such models generically have frozen combinations of Kähler and dilaton moduli. We study concrete bundles with structure group SU(N) × U(1) M yielding quasirealistic gauge groups with chiral matter given by certain bundle cohomology classes. We also provide a number of explicit tadpole free examples of bundles defined by exact sequences of sums of line bundles over complete intersection CalabiYau spaces. This includes one example with precisely the Standard Model gauge symmetry.
BPS Action and Superpotential for Heterotic String Compactifications with Fluxes
, 2003
"... We consider N = 1 compactifications to four dimensions of heterotic string theory in the presence of fluxes. We show that up to order O (α ′2) the associated action can be written as a sum of squares of BPSlike quantities. In this way we prove that the equations of motion are solved by backgrounds ..."
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Cited by 81 (4 self)
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We consider N = 1 compactifications to four dimensions of heterotic string theory in the presence of fluxes. We show that up to order O (α ′2) the associated action can be written as a sum of squares of BPSlike quantities. In this way we prove that the equations of motion are solved by backgrounds which fulfill the supersymmetry conditions and the Bianchi identities. We also argue for the expression of the related superpotential and discuss the radial modulus
Constructing nongeometric vacua in string theory
 Nucl. Phys. B
, 2005
"... In this paper we investigate compactifications of the type II and heterotic string on fourdimensional spaces with nongeometric monodromies. We explicitly construct backgrounds which contain the “Duality Twists ” discussed by Dabholkar and Hull [1]. Similar constructions of nongeometric backgrounds ..."
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Cited by 68 (5 self)
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In this paper we investigate compactifications of the type II and heterotic string on fourdimensional spaces with nongeometric monodromies. We explicitly construct backgrounds which contain the “Duality Twists ” discussed by Dabholkar and Hull [1]. Similar constructions of nongeometric backgrounds have been discussed for type II strings by Hellerman, McGreevy, and Williams [2]. We find that imposing such monodromies projects out many moduli from the resulting vacua and argue that these backgrounds are the spacetime realizations of interpolating asymmetric orbifolds. April 20041. String theory and Geometry String theory, in spite of its aspirations as a fundamental theory of quantum gravity, is for the most part heavily reliant on classical notions of geometry. This being said, it is certainly true that strings and point particles probe classical geometries in dramatically different ways. It is wellknown that strings can resolve many of the singularities that plague classical and quantum gravity. Tduality establishes a remarkable equivalence between strings compactified on large tori with those compactified on small tori. In more general compactifications, one may take this a step further and relate geometries of
Superstring orientifolds with torsion: O5 orientifolds of torus fibrations and their massless spectra
, 2004
"... Using a “Superstrings with Torsion” type description, we study a class of IIB orientifolds in which spacefilling O5 planes and D5 branes wrap the T² fiber in a warped modification of the product of 4D Minkowski space and a T² fibration. For the case that the base is T⁴, we provide examples that pres ..."
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Cited by 37 (5 self)
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Using a “Superstrings with Torsion” type description, we study a class of IIB orientifolds in which spacefilling O5 planes and D5 branes wrap the T² fiber in a warped modification of the product of 4D Minkowski space and a T² fibration. For the case that the base is T⁴, we provide examples that preserve 4D N = 1, 2, and 3 supersymmetry, both with internal RR flux, and with a combination of internal RR and NS flux. In these examples, the internal geometries admit integrable complex structure; however, the almost complex structure selected by the supersymmetry conditions is nonintegrable in the case that there is NS flux. We indicate explicitly the massless spectrum of gauge fields and moduli in each example. In a previous investigation, this class of orientifolds was studied using Tduality. Here, we extend the previous analysis, first by providing an intrinsic description that does not rely on duality, and then by elaborating on details of the Tduality
Towards Minkowski vacua in type II string compactifications
, 2007
"... We study the vacuum structure of compactifications of type II string theories on orientifolds with SU(3) × SU(3) structure. We argue that generalised geometry enables us to treat these nongeometric compactifications using a supergravity analysis in a way very similar to geometric compactifications ..."
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Cited by 29 (2 self)
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We study the vacuum structure of compactifications of type II string theories on orientifolds with SU(3) × SU(3) structure. We argue that generalised geometry enables us to treat these nongeometric compactifications using a supergravity analysis in a way very similar to geometric compactifications. We find supersymmetric Minkowski vacua with all the moduli stabilised at weak string coupling and all the tadpole conditions satisfied. Generically the value of the moduli fields in the vacuum is parametrically controlled and can be taken to arbitrarily large values.
CalabiYau connections with torsion on toric bundles
"... We find sufficient conditions for principal toric bundles over compact Kähler manifolds to admit CalabiYau connections with torsion, as well as conditions to admit strong Kähler connections with torsion. With the aid of a topological classification, we construct such geometry on (k −1)(S 2 ×S 4)#k( ..."
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Cited by 24 (0 self)
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We find sufficient conditions for principal toric bundles over compact Kähler manifolds to admit CalabiYau connections with torsion, as well as conditions to admit strong Kähler connections with torsion. With the aid of a topological classification, we construct such geometry on (k −1)(S 2 ×S 4)#k(S 3 ×S 3) for all k ≥ 1. 1.
Heterotic flux compactifications and their moduli
, 2006
"... We study supersymmetric compactification to four dimensions with nonzero Hflux in heterotic string theory. The background metric is generically conformally balanced and can be conformally Kähler if the primitive part of the Hflux vanishes. Analyzing the linearized variational equations, we write ..."
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Cited by 21 (3 self)
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We study supersymmetric compactification to four dimensions with nonzero Hflux in heterotic string theory. The background metric is generically conformally balanced and can be conformally Kähler if the primitive part of the Hflux vanishes. Analyzing the linearized variational equations, we write down necessary conditions for the existence of moduli associated with the metric. In a heterotic model that is dual to a IIB compactification on an orientifold, we find the metric moduli in a fixed Hflux background via duality and check that they satisfy the required conditions. We also discuss expressing the conditions for moduli in a fixed flux background using twisted differential operators.
Linear models for flux vacua
"... We construct worldsheet descriptions of heterotic flux vacua as the IR limits of N=2 gauge theories. Spacetime torsion is incorporated via a 2d GreenSchwarz mechanism in which a doublet of axions cancels a oneloop gauge anomaly. Manifest (0,2) supersymmetry and the compactness of the gauge theory ..."
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Cited by 18 (3 self)
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We construct worldsheet descriptions of heterotic flux vacua as the IR limits of N=2 gauge theories. Spacetime torsion is incorporated via a 2d GreenSchwarz mechanism in which a doublet of axions cancels a oneloop gauge anomaly. Manifest (0,2) supersymmetry and the compactness of the gauge theory instanton moduli space suggest that these models, which include FuYau models, are stable against worldsheet instantons, implying that they, like CalabiYaus, may be smoothly extended to solutions of the exact beta functions. Since FuYau compactifications are dual to KSTtype flux It is a beautiful and frustrating fact of life that CalabiYaus have interesting moduli spaces. On the one hand, the topology and geometry of their moduli spaces govern the lowenergy physics of string theory compactified on a CalabiYau, so understanding their structure teaches us about fourdimensional stringy physics. On the other, the resulting massless
Open string wavefunctions in flux compactifications
, 2009
"... We consider compactifications of type I supergravity on manifolds with SU(3) structure, in the presence of RR fluxes and magnetized D9branes, and analyze the generalized Dirac and LaplaceBeltrami operators associated to the D9brane worldvolume fields. These compactifications are Tdual to standar ..."
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Cited by 18 (5 self)
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We consider compactifications of type I supergravity on manifolds with SU(3) structure, in the presence of RR fluxes and magnetized D9branes, and analyze the generalized Dirac and LaplaceBeltrami operators associated to the D9brane worldvolume fields. These compactifications are Tdual to standard type IIB toroidal orientifolds with NSNS and RR 3form fluxes and D3/D7 branes. By using techniques of representation theory and harmonic analysis, the spectrum of open string wavefunctions can be computed for Lie groups and their quotients, as we illustrate with explicit twisted tori examples. We find a correspondence between irreducible unitary representations of the KaloperMyers algebra and families of KaluzaKlein excitations. We perform the computation of 2 and 3point couplings for matter fields in the above flux compactifications, and compare our results with those of 4d effective supergravity.