String Dualities and Geometry

14 janv. 2018, 18:00 → 19 janv. 2018, 17:00 America/Buenos_Aires

Aula de conferencias (Centro Atomico Bariloche)

The general goal of the workshop is to bring together experts in different aspects of String Theory, focusing on its duality symmetries and generalized geometry. The last decade has witnessed a growth in the activity in the field, mostly after the advent of the so-called Generalized Geometry and Double/Exceptional Field Theories. In these frameworks the string dualities are promoted to manifest symmetries, highlighting novel generalized geometric structures and exposing emergent stringy physical phenomena. 

 

The workshop will provide a friendly environment to create overlaps between the more formal and physical approaches, find applications of these frameworks, and move forward towards solving important open problems. These include: consistent characterizations of non-geometric backgrounds in string theory, dualities in the absence of isometries and localization in winding space, generalized geometrization of exotic branes, non-associativity and non-commutativity of compact coordinates, duality constraints on higher-derivative interactions, non-Abelian T-duality, implications for the string landscape, etc. 

 

String Dualities and Geometry is expected to help focusing the field and consolidating progress. We hope to welcome you in Bariloche in January.

 

Organisers: Gerardo Aldazabal, Mariana Graña, Diego Marqués, Carmen Núñez

Supporting organisers: Eduardo Andrés, Yago Cagnacci, Eric Lescano, Martín Mayo, Victor Penas

 

SPEAKERS

Eric Bergshoeff

David Berman

Chris Blair

Ralph Blumenhagen

Guillaume Bossard

Yago Cagnacci

Martin Cederwall

Athanasios Chatzistavrakidis

Gianguido Dall'Agata

Giuseppe Dibitetto

Adolfo Guarino

Falk Hassler

Olaf Hohm

Christopher Hull

Gianluca Inverso

Larisa Jonke

Ctirad Klimcik

Oscar Loaiza-Brito

Yolanda Lozano

Dieter Lust

Emanuel Malek

Martin Mayo

Ruben Minasian

Hermann Nicolai

Jeong-Hyuck Park

Michela Petrini

Erik Plauschinn

Fernando Quevedo

Felix Rudolph

Charles Strickland-Constable

Daniel Thompson

Alessandro Tomasiello

Hagen Triendl

Daniel Waldram

Barton Zwiebach

 

 

 

               

         

        

dimanche 14 janvier

18:00 → 20:00 Reception and Registration

Small reception at Hotel Patagonia, located at Av. Exequiel Bustillo 1231. If you miss the reception, please register on Monday during the coffee break.

lundi 15 janvier

09:30 → 10:10 Supersymmetric backgrounds and moduli in generalised geometry

Orateur: Daniel Waldram

10:10 → 10:50 A generalised approach to consistent truncations

We discuss how to formulate consistent truncations with different amount of supersymmetry in the context of generalised geometry and we give some examples.

Orateur: Michela Petrini

petrini.pdf

10:50 → 11:20 Coffee Break

11:20 → 12:00 How to uplift gauged [maximal] supergravities

I will give the general procedure to construct uplifts of gauged supergravities based on generalised parallelisable spaces (i.e. on generalised Scherk-Schwarz reductions). The existence of uplifts, solutions to the section condition as well as the explicit expressions of the parallelisations are algebraically derived from the embedding tensor of the gauged supergravity. Known examples will be rederived and new applications discussed.

Orateur: Gianluca Inverso

Inverso.pdf

12:00 → 14:30 Lunch

14:30 → 15:10 Brane Wess-Zumino terms in String Theory

I will present some old and new results on duality-covariant brane Wess-Zumino terms describing their coupling to supergravity background fields. In particular, I will show how this leads to a classification of branes satisfying interesting wrapping rules and to the introduction of so-called exotic branes.

Orateur: Eric Bergshoeff

Bergshoeff.pdf

15:10 → 15:50 Flatfolds

Orateur: Dall'agata Gianguido

Dallagata.pdf

15:50 → 16:20 Coffee Break

16:20 → 17:00 Classification of doubled-yet-gauged spacetime

A classification of the generalized metric in DFT is presented. Analyses on the particle as well as the string dynamics upon the backgrounds are discussed through doubled-yet-gauged sigma models. DFT describes not only Riemannian gravity but also Newton-Cartan gravity, Carroll geometry or chiral string theories, etc. The talk is based on 1707.03713 with Kevin Morand.

Orateur: Jeong-Hyuck Park

Park.pdf

mardi 16 janvier

09:30 → 10:10 Algebraic structures in double and exceptional field theory

Orateur: Olaf Hohm

Hohm.pdf

10:10 → 10:50 L_infinity algebras and CFT

It is shown that the closure of the infinitesimal symmetry transformations underlying classical (global) W-algebras give rise to L$_\infty$ algebras with in general field dependent gauge parameters. We develop the general formalism for this correspondence and apply it explicitly to the classical W3-algebra. The generalization to the quantum case is discussed as well.

Orateur: Ralph Blumenhagen

Blumenhagen.pdf

10:50 → 11:20 Coffee Break

11:20 → 12:00 Branes in EFT/DFT, exotic and otherwise

Orateur: David Berman

12:00 → 14:30 Lunch

14:30 → 15:10 On higher spin representations of K(E10)

Orateur: Hermann Nicolai

Nicolai.pdf

15:10 → 15:50 Affine generalized diffeomorphisms

Orateur: Guillaume Bossard

Bossard.pdf

15:50 → 16:20 Coffee Break

16:20 → 17:00 Extended Geometries

We present a unified and completely general formulation of extended geometry, characterised by a Kac-Moody algebra and a highest weight coordinate module. Generalised diffeomorphisms are constructed, as well as solutions to the section constraint. Generically, additional ("ancillary") gauge transformations are present, and we give a concrete criterion determining when they appear. A universal form of the (pseudo-)action determines the dynamics in all cases without ancillary transformations, and also for a restricted set of cases based on the adjoint representation of a finite-dimensional simple Lie group. Our construction reproduces (the internal sector of) all previously considered cases of double and exceptional field theories.

Orateur: Martin Cederwall

17:30 → 20:00 Beer @Kunstmann

mercredi 17 janvier

09:30 → 10:10 Non-Abelian T-duality in AdS/CFT: the CFT side

We will discuss recent progress in the understanding of the CFT realization of non-Abelian T-duality when acting on AdS spaces with known CFT duals.

Orateur: Yolanda Lozano

Lozano.pdf

10:10 → 10:50 Generalised T-dualities and Integrable Deformations

In this talk I will present an overview of classes of integrable deformations to sigma models known as lambda and eta deformations. I explain the interesting interplay of the these models with generalisations of T-duality involving both non-Abelian isometries and Poisson-Lie symmetry. I will report on recent work considering the quantum aspects of multi-parameter integrable deformations. For the lambda-XXZ model I shall explain how we can implement its quantisation on a light cone lattice as the Heisenberg XXZ spin chain in the gapless regime. For the eta theory with a WZ term we will discuss aspects of its renormalisation and show how it exhibits an interesting self duality under Poisson-Lie symmetries.

Orateur: Daniel Thompson

Thompson.pdf

10:50 → 11:10 Coffee Break

11:10 → 11:50 Poisson-Lie T-duality in Double Field Theory

Orateur: Falk Hassler

Hassler.pdf

11:50 → 12:30 Hidden isometry of “T-duality without isometry”

We study the T-dualisability criteria of Chatzistavrakidis, Deser and Jonke who recently used Lie algebroid gauge theories to obtain sigma models exhibiting a ``T-duality without isometry''. We point out that those T-dualisability criteria depend on the choice of the algebroid framing. We then show that there always exists an isometric framing for which the Lie algebroid gauging boils down to the standard Yang-Mills gauging recovering thus the traditional isometric non-Abelian T-duality in disguise.

Orateur: Ctirad Klimcik

12:30 → 17:30 Lunch and Free afternoon / Excursion

jeudi 18 janvier

09:30 → 10:10 The structure of a DFT algebroid

In this talk we will discuss some geometric aspects of double field theory. We will argue that the geometric structure of DFT lies in between two pre-Courant algebroids, related to one of them by a projection map and to the other by solving the strong constraint. The structure is not itself a (pre-)Courant algebroid. The proposed picture provides a geometric origin for DFT and its strong constraint, and at the same time it allows for a precise geometric definition of a DFT algebroid.

Orateur: Athanasios Chatzistavrakidis

Chatzis.pdf

10:10 → 10:50 Membrane sigma models and DFT

Based on the one-to-one correspondence between Courant algebroids and membrane sigma models, we propose a membrane sigma model for double field theory. We discuss the relation of the sigma model to the flux formulation of DFT and show that its gauge symmetries reproduce the structure of a DFT algebroid. In addition, we present some examples that clarify its relation to non-geometric string backgrounds. Finally, we discuss the possibility of relaxing the strong constraint of DFT by allowing for a dynamical fiber metric.

Orateur: Larisa Jonke

Jonke.pdf

10:50 → 11:20 Coffee Break

11:20 → 12:00 Non-geometric fluxes and non-associativity in M-theory

In this talk we discuss non-geometric fluxes in M-theory using exceptional field theory. We will point out that there is a new set of non-geometric fluxes in the R-R sector in the perturbative limit. We show that there are missing momenta conditions, induced by the fluxes. Finally the non-geometric fluxes together with the missing momenta lead to a non-associative phase space, which is related to the non-associative algebra of the octonions.

Orateur: Dieter Lust

Luest.pdf

12:00 → 14:30 Lunch

14:30 → 14:50 Locally non-geometric fluxes in M-theory and missing momenta

I will discuss locally non-geometric backgrounds in M-theory. Using duality chains based on twisted tori, I will show that such backgrounds typically have certain missing momentum modes.

Orateur: Emanuel Malek

Malek.pdf

14:50 → 15:10 The exceptional sigma model

I will explain the exceptional sigma model, which describes how a string couples to an exceptional field theory background.

Orateur: Chris Blair

Blair.pdf

15:10 → 15:30 Progress in massive IIA holography

Orateur: Adolfo Guarino

Guarino.pdf

15:30 → 15:50 Universal instabilities of non-susy AdS vacua

Orateur: Giuseppe Dibitetto

15:50 → 16:20 Coffee Break

16:20 → 16:40 T-duality transformations along angular directions for the NS5-brane

I review the uncompactified NS5-brane solution and define in addition to the H-flux a geometric charge for this background. Under T-duality these charge are interchanged, and supersymmetry will be partially broken. These results are compared to the compactified-and-smeared solution, which shows very different behaviour.

Orateur: Erik Plauschinn

16:40 → 17:00 Generalized Kinematics and Dynamics for Double Field Theory

Double Field Theory can be formulated on a 2d-dimensional para-Hermitian manifold ($P,\eta,\omega$) by supplementing the $O(d,d)$ metric $\eta$ with an almost symplectic two-form $\omega$. Together $\eta$ and $\omega$ provide a bi-Lagrangian splitting of the tangent bundle TP into two Lagrangian subspaces. I will sketch how to construct a canonical connection and a corresponding generalized Lie derivative for the Leibniz algebroid on TP. Under certain integrability conditions the symmetry algebra closes for general $\eta$ and $\omega$, even when they are not flat and constant. This provides a generalization of the kinematical structure of DFT. By including the generalized metric $H$ into the setup - which thus becomes para-quaternionic - we can construct a connection compatible with all three structures ($\eta, \omega, H$) and thus can also generalize the dynamics. The precise relation between DFT and generalized geometry is also discussed.

Orateur: Felix Rudolph

Rudolph.pdf

17:00 → 17:20 Supersymmetric brane field theories and non-linear instantons on curved backgrounds

In recent years supersymmetric field theories have been realized on large classes of curved backgrounds, by coupling them to off-shell supergravity backgrounds. I will describe how these field theories are realized in string theory on D-branes in flux backgrounds, and how the auxiliary fields of off-shell supergravity can be matched with the various fluxes of string theory. Finally I will discuss how linear and non-linear supersymmetries and their instantons can be described by using an R-symmetry covariant description.

Orateur: Hagen Triendl

Triendl.pdf

17:20 → 17:40 Moduli mass hierarchy in non-geometric flux compactifications

We study some conditions on which there is a hierarchy on the moduli masses on a type IIB tori compactification in the presence of non-geometrical fluxes.

Orateur: Oscar Loaiza-Brito

17:40 → 18:00 Let’s talk about winding modes again

DFT was, at the beginning, created to incorporate the windings modes and in this way get stringy features in a field theory. But then section condition appeared and all the motivation was lost. In this talk I will speak about new ways of incorporating windings and going beyond the section condition, taking advantage of the enhancement property of string theory.

Orateur: Martin Mayo

Mayo.pdf

18:00 → 18:20 A DFT O(d,d,Z) invariant action including (some) winding modes

Orateur: Yago Cagnacci

Cagnacci.pdf

18:20 → 22:30 Conference Dinner

vendredi 19 janvier

09:30 → 10:10 Duality in Convex Optimization: Application to Minimal Area Surfaces

We define convex programs and describe the construction of dual programs. After explaining the key results of this theory (max-flow min-cut, strong duality, complementary slackness, etc) we apply the methods to find unknown genus one minimal area surfaces.

Orateur: Barton Zwiebach

Zwiebach.pdf

10:10 → 10:50 Non-geometric Calabi-Yau backgrounds

Orateur: Chris Hull

Hull.pdf

10:50 → 11:20 Coffee Break

11:20 → 12:00 TBA

Orateur: Charles Strickland Constable

12:00 → 14:30 Lunch

14:30 → 15:10 AdS classifications

I will review recent classification results about AdS$_d$ compactifications in various dimensions. While the efforts in $d>4$ were originally motivated by holography, several examples should be useful for flux compactifications, for example because of the simultaneous presence of back-reacted sources of different types. In AdS$_7$ we now have a one-line description of all possible solutions. In AdS$_5$ a large class is related to AdS$_7$ by compactification; among these, some interesting examples with ``punctures'' are starting to emerge. Finally, I will talk about classifying AdS$_4$ solutions with extended supersymmetry.

Orateur: Alessandro Tomaseillo

Tomasiello.pdf

15:10 → 15:50 Supersymmetry and geometry of stringy corrections

I’ll try to review why there are still open questions (that we should care about) concerning the structure of stringy corrections to low energy effective actions and if/how generalised geometry can help to answer these.

Orateur: Ruben Minasian

15:50 → 16:20 Coffee Break

16:20 → 17:00 Is String Phenomenology an Oxymoron?

Orateur: Fernando Quevedo

Quevedo.pdf