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Larfors, Magdalena
Publications (10 of 13) Show all publications
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
Open this publication in new window or tab >>The Infinitesimal Moduli Space of Heterotic G2 Systems
2018 (English)In: Communications in Mathematical Physics, ISSN 0010-3616, E-ISSN 1432-0916, Vol. 360, no 2, p. 727-775Article in journal (Refereed) 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.

National Category
Subatomic Physics Other Physics Topics
Identifiers
urn:nbn:se:uu:diva-356865 (URN)10.1007/s00220-017-3013-8 (DOI)000431873000009 ()
Funder
Swedish Research Council, 2016-03873
Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2018-08-09Bibliographically approved
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
Open this publication in new window or tab >>Generalised Geometry and Flux Vacua: A very short review
2016 (English)Conference paper, Published paper (Refereed)
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.

Series
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS, ISSN 0015-8208
Keywords
vacuum state: flux | compactification: flux | geometry: complex | supersymmetry: constraint | integrability | F-theory | string model: Type II | exceptional
National Category
Subatomic Physics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:uu:diva-288097 (URN)10.1002/prop.201500082 (DOI)000374266000013 ()
Conference
21st European String Workshop on String Theory Universe / 3rd COST MP1210 Meeting
Available from: 2016-04-27 Created: 2016-04-27 Last updated: 2016-07-15Bibliographically approved
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.
Open this publication in new window or tab >>Infinitesimal moduli of G2 holonomy manifolds with instanton bundles
2016 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 11, article id 016Article in journal (Refereed) 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.

Place, publisher, year, edition, pages
SPRINGER, 2016
Keywords
Superstrings and Heterotic Strings, Differential and Algebraic Geometry, Superstring Vacua
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-322003 (URN)10.1007/JHEP11(2016)016 (DOI)000399293300001 ()
Available from: 2017-05-15 Created: 2017-05-15 Last updated: 2017-05-15Bibliographically approved
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.
Open this publication in new window or tab >>4 Type IIB flux vacua from G-theory I
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2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 2, article id 187Article in journal (Refereed) 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.

Keywords
Flux compactifications, Superstring Vacua, String Duality
National Category
Other Physics Topics
Identifiers
urn:nbn:se:uu:diva-251522 (URN)10.1007/JHEP02(2015)187 (DOI)000350696300002 ()
Available from: 2015-04-22 Created: 2015-04-20 Last updated: 2017-12-04Bibliographically approved
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
Open this publication in new window or tab >>Exploring SU(3) structure moduli spaces with integrable G(2) structures
2015 (English)In: Advances in Theoretical and Mathematical Physics, ISSN 1095-0761, E-ISSN 1095-0753, Vol. 19, no 4, p. 837-903Article in journal (Refereed) 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.

National Category
Physical Sciences Mathematics
Identifiers
urn:nbn:se:uu:diva-280122 (URN)000368916600005 ()
Funder
Swedish Research Council, 623-2011-7205
Available from: 2016-03-08 Created: 2016-03-08 Last updated: 2017-11-30Bibliographically approved
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.
Open this publication in new window or tab >>Type IIB flux vacua from G-theory II
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2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 2, article id 188Article in journal (Refereed) 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.

Keywords
Flux compactifications, Superstring Vacua, String Duality
National Category
Other Physics Topics
Identifiers
urn:nbn:se:uu:diva-251523 (URN)10.1007/JHEP02(2015)188 (DOI)000350696300003 ()
Available from: 2015-04-22 Created: 2015-04-20 Last updated: 2017-12-04Bibliographically approved
Larfors, M. (2009). Pierced, Wrapped and Torn: Aspects of String Theory Compactifications. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Pierced, Wrapped and Torn: Aspects of String Theory Compactifications
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
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.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2009. p. 134
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 632
National Category
Other Physics Topics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:uu:diva-100503 (URN)978-91-554-7494-2 (ISBN)
Public defence
2009-05-15, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2009-04-24 Created: 2009-04-01 Last updated: 2009-05-11Bibliographically approved
Chialva, D., Danielsson, U. H., Johansson, N., Larfors, M. & Vonk, M. (2008). Deforming, revolving and resolving: New paths in the string theory landscape. Journal of High Energy Physics (JHEP), 02, Article ID 016.
Open this publication in new window or tab >>Deforming, revolving and resolving: New paths in the string theory landscape
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2008 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 02, article id 016Article in journal (Refereed) Published
Abstract [en]

In this paper we investigate the properties of series of vacua in the string theory landscape. In particular, we study minima to the flux potential in type IIB compactifications on the mirror quintic. Using geometric transitions, we embed its one-dimensional complex structure moduli space in that of another Calabi-Yau with h1,1 = 86 and h2,1 = 2. We then show how to construct infinite series of continuously connected minima to the mirror quintic potential by moving into this larger moduli space, applying its monodromies, and moving back. We provide an example of such series, and discuss their implications for the string theory landscape

Keywords
Superstring Vacua, Flux compactifications
National Category
Physical Sciences
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:uu:diva-100502 (URN)10.1088/1126-6708/2008/02/016 (DOI)000254764400096 ()
Available from: 2009-04-01 Created: 2009-04-01 Last updated: 2017-12-13Bibliographically approved
Johnson, M. C. & Larfors, M. (2008). Field dynamics and tunneling in a flux landscape. Physical Review D. Particles and fields, 78(8), 0835341-08353423
Open this publication in new window or tab >>Field dynamics and tunneling in a flux landscape
2008 (English)In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 78, no 8, p. 0835341-08353423Article in journal (Refereed) Published
Place, publisher, year, edition, pages
American Physical Society, 2008
National Category
Other Physics Topics
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-100308 (URN)10.1103/PhysRevD.78.083534 (DOI)
Available from: 2009-03-30 Created: 2009-03-30 Last updated: 2017-12-13Bibliographically approved
Johnson, M. C. & Larfors, M. (2008). Obstacle to populating the string theory landscape. Physical Review D. Particles and fields, 78(12), 1235131-1235135
Open this publication in new window or tab >>Obstacle to populating the string theory landscape
2008 (English)In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 78, no 12, p. 1235131-1235135Article in journal (Refereed) Published
Abstract [en]

We construct domain walls and instantons in a class of models with coupled scalar fields, determining, in agreement with previous studies, that many such solutions contain naked timelike singularities. Vacuum bubble solutions of this type do not contain a region of true vacuum, obstructing the ability of eternal inflation to populate other vacua. We determine a criterion that potentials must satisfy to avoid the existence of such singularities and show that many domain wall solutions in type IIB string theory are singular.

Place, publisher, year, edition, pages
American Physical Society, 2008
National Category
Physical Sciences
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:uu:diva-100500 (URN)10.1103/PhysRevD.78.123513 (DOI)
Available from: 2009-04-01 Created: 2009-04-01 Last updated: 2017-12-13Bibliographically approved
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