Double Field Theory on Group Manifolds

• Falk Haßler (MPI for Physics, Munich)

Room: 4-3-006 - TH Conference Room

Loops in exceptional field theory

• Axel Kleinschmidt (MPI Potsdam)

Room: 4-3-006 - TH Conference Room

How many coordinates does DFT have?

• Georgios PAPADOPOULOS (Kings College London)

Room: 4-3-006 - TH Conference Room I shall describe the puzzles and challenges that rise in attempting to globally patch DFT. Then I shall propose a new class of spaces, the C-spaces, which contain locally the doubled spaces and resolve some of the puzzles. I shall also explain the relation of C-spaces to generalized geometry, and describe how the 3-form flux is geometrised. Some topological aspects of the geometrisation of fluxes, in particular the relation to Whitehead towers, will be explored.

T-duality and alpha-prime corrections

• Diego Marqués (IAFE Buenos Aires)

Room: 4-3-006 - TH Conference Room I will discuss recent results on T-duality symmetric descriptions of four-derivative terms in string effective actions.

On (4+6)-dimensional SUSY vacua with non-geometric fluxes

• David Andriot (MPI, AEI Potsdam-Golm)

Room: 4-3-006 - TH Conference Room In the 10-dimensional framework of beta-supergravity, we characterize (4+6)-dimensional vacua preserving supersymmetry. We rewrite Killing spinor equations with NSNS non-geometric fluxes using the language of SU(3)*SU(3) structures and Generalized Complex Geometry, in analogy to standard type II supergravities. The NSNS generalized differential operator D that appears exhibits interesting properties, among which being a Generalized Dirac operator. This formulation leads us to a general expression for the superpotential, and we successfully compare it to existing formulas in the literature.

Double field theory and stringy geometry

• Chris M Hull (Imperial College)

Room: 4-3-006 - TH Conference Room

alpha' corrections in double field theory

• Olaf Hohm (MIT)

Room: 4-3-006 - TH Conference Room

Double extension of N=4 super-Yang-Mills theory

• Soo-Jong Rey (Seoul National University & IBS)

Room: 4-3-006 - TH Conference Room

Exceptional geometry and Borcherds superalgebras

• Jakob Palmkvist (Texas A&M University)

Room: 4-3-006 - TH Conference Room I will consider generalized diffeomorphisms in exceptional geometry from an algebraic point of view. By extending the U-duality algebra E_n to an infinite-dimensional Lie superalgebra of Borcherds type, the generalized Lie derivatives can be expressed in a simple way, and the expression takes the same form for any n<8. The closure of the transformations then follows from the Jacobi identity and other fundamental properties of this Borcherds superalgebra.

Consistent Scherk-Schwarz compactifications using exceptional field theory

• Emanuel Malek (LMU Munich)

Room: 4-3-006 - TH Conference Room We discuss 7-dimensional maximal gauged supergravities arising from Scherk-Schwarz compactifications using exceptional field theory. We show how to map consistent compactifications of 10-dimensional type IIA theory into consistent compactifications of 10-dimensional type IIB theory and vice versa and show how this map transforms the resultant gaugings of the 7-dimensional embedding tensor. We use this map to extend the known consistent compactifications of10-dimensional type IIA theory on hyperboloidal spaces $H^{p,q}$ to compactifications of 10-dimensional type IIB theory on such $H^{p,q}$ spaces.

E8 geometry

• Martin Cederwall

Room: 4-3-006 - TH Conference Room We investigate exceptional generalised diffeomorphisms based on E_8(8) in a geometric setting. The transformations include gauge transformations for the dual gravity field. The surprising key result, which allows for a development of a tensor formalism, is that it is possible to define field-dependent transformations containing connection, which are covariant. We solve for the spin connection and construct a curvature tensor. A geometry for the Ehlers symmetry SL(n + 1) is sketched. Some related issues are discussed. If time allows I will also discuss solution (and relaxation) of the section condition in terms of a twistor transform in a first-quantised setting.

New gaugings and non-geometry

• Charles Strickland-Constable (CEA Saclay)

Room: 4/3-006 - TH Conference Room

Conserved charges in double field theory

• Chris Blair (University of Cambridge)

Room: 4-3-006 - TH Conference Room

Solutions in Extended Field Theories

• Felix Rudolph (Queen Mary London)

Room: 4-3-006 - TH Conference Room I will present solutions to Double Field Theory and Exceptional Field Theory and show that the string is a null wave in DFT and the NS5-brane is a monopole. Extending these solutions to EFT where S-duality is part of the symmetry group gives a single self-dual solution combining both the wave and a monopole. Through taking different choices of the section condition, this solution yields all the 1/2 BPS solutions in M-theory.

Doubled-yet-gauged and twofold spin groups

• Jeong-Hyuck Park (Sogang University)

Room: 4-3-006 - TH Conference Room

Supersymmetric gauged DFT

• Jose J. FERNANDEZ-MELGAREJO (Harvard University)

Room: 4-3-006 - TH Conference Room In a systematic and geometric way, we derive maximal and half-maximal supersymmetric gauged double field theories in lower than ten dimensions. To this end, we apply a simple twisting ansatz to the D=10 ungauged maximal and half-maximal supersymmetric double field theories constructed previously. The twisting ansatz may not satisfy the section condition. In addition, the maximal supersymmetric twist requires an extra condition to ensure both the Ramond-Ramond gauge symmetry and the 32 supersymmetries unbroken. Based on http://arxiv.org/abs/1505.01301

Weakly Constrained Double Field Theory

• Kanghoon Lee (Korea Institute for Advanced Study)

Room: 4-3-006 - TH Conference Room

TBA

• Edvard Musaev (Higher School of Economics, Faculty of Mathematics, Moscow)

Room: 4-3-006 - TH Conference Room

Double Sigma Model

• Chen-Te Ma (National Taiwan University)

Room: 4-3-006 - TH Conference Room Double sigma model with strong constraints is equivalent to the ordinary sigma model by imposing a self-duality relation. The gauge symmetries are the diffeomorphism and one-form gauge transformation with the strong constraints. We combine the antisymmetric background field with the field strength to redefine the generalized metric. We use this generalized metric to construct a consistent double sigma model with boundary conditions. We also give comments to non-commutative geometry in the double sigma model.

Holographic Entanglement entropy and central charge in CFT's

• Mohsen Alishahiha (IPM Teheran)

Room: 4-3-006 - TH Conference Room

Gauging of 2D sigma models without isometry and genuinely non-geometric backgrounds from 3D sigma models.

• Athanasios CHATZISTAVRAKIDIS (Leibnitz University Hannover)

Room: 4-3-006 - TH Conference Room In this talk we discuss two problems in the context of sigma models motivated by recent studies in T-duality and non-geometry. The first problem refers to the gauging of 2D sigma models when there is no isometry available, while the second regards the possibility to construct genuinely non-geometric backgrounds with the aid of 3D sigma models. In both cases the underlying mathematical framework is the theory of Lie and Courant algebroids, which will be presented in the first part of the talk. Then we shift our attention to a general class of 2D theories called Dirac sigma models and present a novel way to gauge such theories. This gauging is useful in formulating T-duality even when there is no isometry. Finally we discuss the correspondence between Courant algebroids and AKSZ membrane models with boundary. A certain class of such theories offers the possibility to construct non-geometric models which do not possess a geometric dual.

Metastring theory

• Rob Leigh (University of Illinois)

Room: 4-3-006 - TH Conference Room

Enhanced gauge symmetry and winding states in Double Field Theory

• Jose Alejandro ROSABAL RODRIGUEZ (Universidad de Buenos Aires)

Room: 4-3-006 - TH Conference Room

U-gravity for SL(N)

• Yoonji Suh (Sogang University)

Room: 4-3-006 - TH Conference Room We construct a duality manifest gravitational theory for the special linear group, SL(N) with N≠4. The spacetime is formally extended, to have the dimension 12N(N−1), yet is `gauged'. Consequently the theory is subject to a section condition. We introduce a semi-covariant derivative and a semi-covariant `Riemann' curvature, both of which can be completely covariantized after symmetrizing or contracting the SL(N) vector indices properly. Fully covariant scalar and `Ricci' curvatures then constitute the action and the `Einstein' equation of motion. For N≥5, the section condition admits duality inequivalent two solutions, one (N−1)-dimensional and the other three-dimensional. In each case, the theory can describe not only Riemannian but also non-Riemannian backgrounds.

Codimension two solutions in five-dimensional supergravity

• Masaki Shigemori (Kyoto University)

Room: 4-3-006 - TH Conference Room We study a new class of supersymmetric solutions in five-dimensional supergravity representing multi-center configurations of codimension-2 branes along arbitrary curves. Codimension-2 branes are produced in generic situations out of ordinary branes of higher codimension by the supertube effect and, when they are exotic branes, spacetime generally becomes non-geometric. The solutions are characterized by a set of harmonic functions on R^3 with non-trivial monodromies around codimension-2 branch-point singularities. The solutions can be regarded as generalizations of the Bates-Denef/Bena-Warner multi-center solutions with codimension-3 centers to include codimension-2 ones. We present some explicit examples of solutions with codimension-2 centers, and discuss their relevance for the black microstate (non-)geometry program. ref: 1505.05169