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Larfors, Magdalena
Publikasjoner (10 av 17) Visa alla publikasjoner
Larfors, M., Lukas, A. & Ruehle, F. (2019). Calabi-Yau manifolds and SU(3) structure. Journal of High Energy Physics (JHEP) (1), Article ID 171.
Åpne denne publikasjonen i ny fane eller vindu >>Calabi-Yau manifolds and SU(3) structure
2019 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 1, artikkel-id 171Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We show that non-trivial SU(3) structures can be constructed on large classes of Calabi-Yau three-folds. Specifically, we focus on Calabi-Yau three-folds constructed as complete intersections in products of projective spaces, although we expect similar methods to apply to other constructions and also to Calabi-Yau four-folds. Among the wide range of possible SU(3) structures we find Strominger-Hull systems, suitable for heterotic or type II string compactifications, on all complete intersection Calabi-Yau manifolds. These SU(3) structures of Strominger-Hull type have a non-vanishing and non-closed three-form flux which needs to be supported by source terms in the associated Bianchi identity. We discuss the possibility of finding such source terms and present first steps towards their explicit construction. Provided suitable sources exist, our methods lead to Calabi-Yau compactifications of string theory with a non Ricci-flat, physical metric which can be written down explicitly and in analytic form.

sted, utgiver, år, opplag, sider
SPRINGER, 2019
Emneord
Flux compactifications, Superstring Vacua, Superstrings and Heterotic Strings
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-376825 (URN)10.1007/JHEP01(2019)171 (DOI)000456586600002 ()
Forskningsfinansiär
Swedish Research Council, 2016-03873
Tilgjengelig fra: 2019-02-14 Laget: 2019-02-14 Sist oppdatert: 2019-02-14bibliografisk kontrollert
Braun, A. P., Del Zotto, M., Halverson, J., Larfors, M., Morrison, D. R. & Schafer-Nameki, S. (2018). Infinitely many M2-instanton corrections to M-theory on G(2)-manifolds. Journal of High Energy Physics (JHEP) (9), Article ID 077.
Åpne denne publikasjonen i ny fane eller vindu >>Infinitely many M2-instanton corrections to M-theory on G(2)-manifolds
Vise andre…
2018 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 9, artikkel-id 077Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We consider the non-perturbative superpotential for a class of four-dimensional N = 1 vacua obtained from M-theory on seven-manifolds with holonomy G(2). The class of G(2)-holonomy manifolds we consider are so-called twisted connected sum (TCS) constructions, which have the topology of a K3-fibration over S-3. We show that the non-perturbative superpotential of M-theory on a class of TCS geometries receives infinitely many inequivalent M2-instanton contributions from infinitely many three-spheres, which we conjecture are supersymmetric (and thus associative) cycles. The rationale for our construction is provided by the duality chain of [1], which relates M-theory on TCS G(2) manifolds to E-8 x E-8 heterotic backgrounds on the Schoen Calabi-Yau threefold, as well as to F-theory on a K3-fibered Calabi-Yau fourfold. The latter are known to have an infinite number of instanton corrections to the superpotential and it is these contributions that we trace through the duality chain back to the G(2)-compactification.

sted, utgiver, år, opplag, sider
SPRINGER, 2018
Emneord
Differential and Algebraic Geometry, String Duality, F-Theory, M-Theory
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-366742 (URN)10.1007/JHEP09(2018)077 (DOI)000444680100012 ()
Forskningsfinansiär
EU, European Research Council, 682608Swedish Research Council, 2016-03873
Tilgjengelig fra: 2018-12-10 Laget: 2018-12-10 Sist oppdatert: 2018-12-10bibliografisk kontrollert
de la Ossa, X., Larfors, M. & Svanes, E. E. (2018). The Infinitesimal Moduli Space of Heterotic G2 Systems. Communications in Mathematical Physics, 360(2), 727-775
Åpne denne publikasjonen i ny fane eller vindu >>The Infinitesimal Moduli Space of Heterotic G2 Systems
2018 (engelsk)Inngår i: Communications in Mathematical Physics, ISSN 0010-3616, E-ISSN 1432-0916, Vol. 360, nr 2, s. 727-775Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Heterotic string compactifications on integrable G(2) structure manifolds Y with instanton bundles (V, A), (TY, (theta) over tilde )yield supersymmetric three-dimensional vacua that are of interest in physics. In this paper, we define a covariant exterior derivative D and show that it is equivalent to a heterotic G(2) system encoding the geometry of the heterotic string compactifications. This operator D acts on a bundle Q = T*Y circle plus End (V) circle plus End (TY) and satisfies a nilpotency condition (sic)(2) = 0, for an appropriate projection of D. Furthermore, we determine the infinitesimal moduli space of these systems and show that it corresponds to the finite-dimensional cohomology group (sic)(1)((sic)) (Q). We comment on the similarities and differences of our result with Atiyah's well-known analysis of deformations of holmorphic vector bundles over complex manifolds. Our analysis leads to results that are of relevance to all orders in the alpha' expansion.

HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-356865 (URN)10.1007/s00220-017-3013-8 (DOI)000431873000009 ()
Forskningsfinansiär
Swedish Research Council, 2016-03873
Tilgjengelig fra: 2018-08-09 Laget: 2018-08-09 Sist oppdatert: 2018-08-09bibliografisk kontrollert
de la Ossa, X., Larfors, M. & Svanes, E. E. (2017). Restrictions of Heterotic G2 Structures and Instanton Connections. In: Proceedings, Nigel Hitchin’s 70th Birthday Conference: Geometry and Physics : A Festschrift in honour of Nigel Hitchin : 2 volumes: Aarhus, Denmark, Oxford, UK, Madrid, Spain, September 5-16, 2016. Paper presented at Proceedings, Nigel Hitchin's 70th Birthday Conference : Geometry and Physics : A Festschrift in honour of Nigel Hitchin : 2 volumes : Aarhus, Denmark, Oxford, UK, Madrid, Spain, September 5-16, 2016. Oxford: Oxford University Press
Åpne denne publikasjonen i ny fane eller vindu >>Restrictions of Heterotic G2 Structures and Instanton Connections
2017 (engelsk)Inngår i: Proceedings, Nigel Hitchin’s 70th Birthday Conference: Geometry and Physics : A Festschrift in honour of Nigel Hitchin : 2 volumes: Aarhus, Denmark, Oxford, UK, Madrid, Spain, September 5-16, 2016, Oxford: Oxford University Press, 2017Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

This note revisits recent results regarding the geometry and moduli of solutions of the heterotic string on manifolds Y with a G2 structure. In particular, such heterotic G2 systems can be rephrased in terms of a differential Dˇ acting on a complex Ωˇ∗(Y,Q), where Q=T∗Y⊕End(TY)⊕End(V), and Dˇ is an appropriate projection of an exterior covariant derivative D which satisfies an instanton condition. The infinitesimal moduli are further parametrized by the first cohomology H1Dˇ(Y,Q). We proceed to restrict this system to manifolds X with an SU(3) structure corresponding to supersymmetric compactifications to four-dimensional Minkowski space, often referred to as Strominger–Hull solutions. In doing so, we derive a new result: the Strominger-Hull system is equivalent to a particular holomorphic Yang–Mills covariant derivative on Q|X=T∗X⊕End(TX)⊕End(V).

sted, utgiver, år, opplag, sider
Oxford: Oxford University Press, 2017
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-371271 (URN)10.1093/oso/9780198802020.003.0020 (DOI)9780198802020 (ISBN)
Konferanse
Proceedings, Nigel Hitchin's 70th Birthday Conference : Geometry and Physics : A Festschrift in honour of Nigel Hitchin : 2 volumes : Aarhus, Denmark, Oxford, UK, Madrid, Spain, September 5-16, 2016
Forskningsfinansiär
Swedish Research Council, 2016-03873
Tilgjengelig fra: 2018-12-20 Laget: 2018-12-20 Sist oppdatert: 2019-03-15bibliografisk kontrollert
Larfors, M. (2016). Generalised Geometry and Flux Vacua: A very short review. In: : . Paper presented at 21st European String Workshop on String Theory Universe / 3rd COST MP1210 Meeting (pp. 354-360). , 64
Åpne denne publikasjonen i ny fane eller vindu >>Generalised Geometry and Flux Vacua: A very short review
2016 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

This note discusses the connection between generalised geometry and flux compactifications of string theory. Firstly, we explain in a pedestrian manner how the supersymmetry constraints of type II flux compactifications can be restated as integrability constraints on certain generalised complex structures. This reformulation uses generalised complex geometry, a mathematical framework that geometrizes the B-field. Secondly, we discuss how exceptional generalised geometry may provide a similar geometrization of the RR fields. Thirdly, we examine the connection between generalised geometry and non-geometry, and finally we present recent developments where generalised geometry is used to construct explicit examples of flux compactifications to flat space.

Serie
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS, ISSN 0015-8208
Emneord
vacuum state: flux | compactification: flux | geometry: complex | supersymmetry: constraint | integrability | F-theory | string model: Type II | exceptional
HSV kategori
Forskningsprogram
Teoretisk fysik
Identifikatorer
urn:nbn:se:uu:diva-288097 (URN)10.1002/prop.201500082 (DOI)000374266000013 ()
Konferanse
21st European String Workshop on String Theory Universe / 3rd COST MP1210 Meeting
Tilgjengelig fra: 2016-04-27 Laget: 2016-04-27 Sist oppdatert: 2016-07-15bibliografisk kontrollert
de la Ossa, X., Larfors, M. & Svanes, E. E. (2016). Infinitesimal moduli of G2 holonomy manifolds with instanton bundles. Journal of High Energy Physics (JHEP) (11), Article ID 016.
Åpne denne publikasjonen i ny fane eller vindu >>Infinitesimal moduli of G2 holonomy manifolds with instanton bundles
2016 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 11, artikkel-id 016Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We describe the infinitesimal moduli space of pairs (Y, V) where Y is a manifold with G(2) holonomy, and V is a vector bundle on Y with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical G(2) cohomology developed by Reyes-Carrion and Fern\'andez and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli H-d(sic)A(1)(Y, End(V)) plus the moduli of the G(2) structure preserving the instanton condition. The latter piece is contained in H-d(sic)theta(1)(Y, TY), and is given by the kernel of a map F(sic) which generalises the concept of the Atiyah map for holomorphic bundles on complex manifolds to the case at hand. In fact, the map F(sic) is given in terms of the curvature of the bundle and maps H-d(sic)theta(1)(Y, TY) into H-d(sic)A(2) (Y, End(V)), and moreover can be used to define a cohomology on an extension bundle of TY by End(V). We comment further on the resemblance with the holomorphic Atiyah algebroid and connect the story to physics, in particular to heterotic compactifications on (Y,V) when alpha'=0.

sted, utgiver, år, opplag, sider
SPRINGER, 2016
Emneord
Superstrings and Heterotic Strings, Differential and Algebraic Geometry, Superstring Vacua
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-322003 (URN)10.1007/JHEP11(2016)016 (DOI)000399293300001 ()
Tilgjengelig fra: 2017-05-15 Laget: 2017-05-15 Sist oppdatert: 2017-05-15bibliografisk kontrollert
Candelas, P., Constantin, A., Damian, C., Larfors, M. & Morales, J. F. (2015). 4 Type IIB flux vacua from G-theory I. Journal of High Energy Physics (JHEP) (2), Article ID 187.
Åpne denne publikasjonen i ny fane eller vindu >>4 Type IIB flux vacua from G-theory I
Vise andre…
2015 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 2, artikkel-id 187Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We construct non-perturbatively exact four-dimensional Minkowski vacua of type IIB string theory with non-trivial fluxes. These solutions are found by gluing together, consistently with U-duality, local solutions of type IIB supergravity on T-4 x C with the metric, dilaton and flux potentials varying along C and the flux potentials oriented along T-4. We focus on solutions locally related via U-duality to non-compact Ricci-flat geometries. More general solutions and a complete analysis of the supersymmetry equations are presented in the companion paper [1]. We build a precise dictionary between fluxes in the global solutions and the geometry of an auxiliary K3 surface fibered over CP1. In the spirit of F-theory, the flux potentials are expressed in terms of locally holomorphic functions that parametrize the complex structure moduli space of the K3 fiber in the auxiliary geometry. The brane content is inferred from the monodromy data around the degeneration points of the fiber.

Emneord
Flux compactifications, Superstring Vacua, String Duality
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-251522 (URN)10.1007/JHEP02(2015)187 (DOI)000350696300002 ()
Tilgjengelig fra: 2015-04-22 Laget: 2015-04-20 Sist oppdatert: 2017-12-04bibliografisk kontrollert
de la Ossa, X., Larfors, M. & Svanes, E. E. (2015). Exploring SU(3) structure moduli spaces with integrable G(2) structures. Advances in Theoretical and Mathematical Physics, 19(4), 837-903
Åpne denne publikasjonen i ny fane eller vindu >>Exploring SU(3) structure moduli spaces with integrable G(2) structures
2015 (engelsk)Inngår i: Advances in Theoretical and Mathematical Physics, ISSN 1095-0761, E-ISSN 1095-0753, Vol. 19, nr 4, s. 837-903Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We study the moduli space of SU(3) structure manifolds X that form the internal compact spaces in four-dimensional N = 1/2 domain wall solutions of heterotic supergravity with flux. Together with the direction perpendicular to the four-dimensional domain wall, X forms a non-compact 7-manifold Y with torsionful G(2) structure. We use this G(2) embedding to explore how X(t) varies along paths C(t) in the SU(3) structure moduli space. Our analysis includes the Bianchi identities which strongly constrain the flow. We show that requiring that the SU(3) structure torsion is preserved along the path leads to constraints on the G(2) torsion and the embedding of X in Y. Furthermore, we study flows along which the torsion classes of X go from zero to non-zero values. In particular, we present evidence that the flow of half-flat SU(3) structures may contain Calabi-Yau loci, in the presence of non-vanishing H-flux.

HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-280122 (URN)000368916600005 ()
Forskningsfinansiär
Swedish Research Council, 623-2011-7205
Tilgjengelig fra: 2016-03-08 Laget: 2016-03-08 Sist oppdatert: 2017-11-30bibliografisk kontrollert
Candelas, P., Constantin, A., Damian, C., Larfors, M. & Morales, J. F. (2015). Type IIB flux vacua from G-theory II. Journal of High Energy Physics (JHEP) (2), Article ID 188.
Åpne denne publikasjonen i ny fane eller vindu >>Type IIB flux vacua from G-theory II
Vise andre…
2015 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 2, artikkel-id 188Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We find analytic solutions of type IIB supergravity on geometries that locally take the form Mink x M-4 x C with M-4 a generalised complex manifold. The solutions involve the metric, the dilaton, NSNS and RR flux potentials (oriented along the M-4) parametrised by functions varying only over C. Under this assumption, the supersymmetry equations are solved using the formalism of pure spinors in terms of a finite number of holomorphic functions. Alternatively, the solutions can be viewed as vacua of maximally supersymmetric supergravity in six dimensions with a set of scalar fields varying holomorphically over C. For a class of solutions characterised by up to five holomorphic functions, we outline how the local solutions can be completed to four-dimensional flux vacua of type IIB theory. A detailed study of this global completion for solutions with two holomorphic functions has been carried out in the companion paper [1]. The fluxes of the global solutions are, as in F-theory, entirely codified in the geometry of an auxiliary K3 fibration over CP1. The results provide a geometric construction of fluxes in F-theory.

Emneord
Flux compactifications, Superstring Vacua, String Duality
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-251523 (URN)10.1007/JHEP02(2015)188 (DOI)000350696300003 ()
Tilgjengelig fra: 2015-04-22 Laget: 2015-04-20 Sist oppdatert: 2017-12-04bibliografisk kontrollert
Larfors, M. (2009). Pierced, Wrapped and Torn: Aspects of String Theory Compactifications. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Åpne denne publikasjonen i ny fane eller vindu >>Pierced, Wrapped and Torn: Aspects of String Theory Compactifications
2009 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

An outstanding problem in physics is to find a unified framework for quantum mechanics and general relativity. This is required for a better understanding of black holes and the early cosmology of the universe. String theory provides such a unification. In this thesis, we study aspects of compactifications of type IIB string theory. In the first part of the thesis, we study four-dimensional black holes consisting of D3-branes wrapping cycles in the compact dimensions. We discuss the correspondence between these black holes, topological string theory and matrix models. We then study the influence of black holes on the stability of flux compactifications. In the second part of the thesis, we turn to investigations of the type IIB landscape, i.e. the collection of stable and metastable vacua obtained from flux compactifications on conformal Calabi-Yau manifolds. We show that monodromies are important for the topographic structure of the landscape. In particular we find that there are long series of continuously connected vacua in the complex structure moduli space of the internal manifold. We also use geometric transitions to connect the moduli spaces of different manifolds, and create longer series of vacua. Finally, we investigate the stability of string theory vacua by constructing semiclassical instantons. These results have implications for the population of the landscape by eternal inflation.

sted, utgiver, år, opplag, sider
Uppsala: Acta Universitatis Upsaliensis, 2009. s. 134
Serie
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 632
HSV kategori
Forskningsprogram
teoretisk fysik
Identifikatorer
urn:nbn:se:uu:diva-100503 (URN)978-91-554-7494-2 (ISBN)
Disputas
2009-05-15, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2009-04-24 Laget: 2009-04-01 Sist oppdatert: 2009-05-11bibliografisk kontrollert
Organisasjoner