Past seminars

Academic year: September 2007 - September 2008

Most studies of supersymmetric dark matter use constrained MSSM models. I will discuss neutralino dark matter in the light of effective field theory. There has been rapid progress in deriving effective actions from string theory in the last few years, and I give an overview of some work in progress in this direction.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, June 18, 2008 at 13:00

We study the supersymmetric solutions of N=2,d=4 Super-Einstein-Yang-Mills Theories and find a recipe to construct all those in the timelike class starting from any solution of the well- known Bogomol'nyi equations in R3. Then, we take several of these solutions (those that lead to the 't Hooft-Polyakov monopole in flat spacetime plus other solutions that are usually discarded because they are singular in R3) and follow the recipe to construct the complete supergravity solutions. We find globally-regular monopole spacetimes and also regular black-hole spacetimes corresponding to some of the singular solutions of the Bogomol'nyi equations. The singularities in R3 are not such once the non-trivial structure of the spacetime is taken into account. We also find generalizations of the Bartnik-McKinnon and Bizon's non-Abelian black holes, but all our solutions will be fully analytical. We will also discuss how the attractor mechanism is implemented in these solutions.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, June 18, 2008 at 10:30

After a brief general introduction I focus on toric geometry constructions of Calabi-Yau manifolds and report on recent results on the exploration of the web via conifold transitions, which provided a surprisignly rich set of new Calabi-Yau 3-folds with a small number of parameters. I also mention applications to phenomenology, including moduli stabilization in heterotic `standard models' via instantons on torsion curves.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, June 11, 2008 at 13:00

I will review some recent results in the ongoing programme to classify supersymmetric supergravity solutions. This include the proof that the maximal fraction of preserved supersymmetry in IIB not implying maximal supersymmetry is 7/8, i.e. solutions preserving more than 28 supersymmetries enhance to become maximally supersymmetric. Furthermore, the derivation of all possible isotropy groups, and associated Sigma groups, for spinors in 10 and 11 dimensions will be explained, in particular the connection between the Sigma groups and the R-symmetry groups of lower-dimensional supergravity theories. Finally, the classification of all supersymmetric geometries of N=1 supergravity, with four supercharges, in four dimensions coupled to any number of vector and scalar multiplets will be reviewed.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, June 11, 2008 at 10:30

I present a Hamiltonian formulation of 4-d gravity designed so that the electric-magnetic duality properties of the theory manifest themselves and their role in holography is clarified. Explicit examples are presented. The formalism can be useful for the study of generalized electric-magnetic duality of higher-spin fields.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, June 4, 2008 at 13:00

A modified version of the double potential formalism for the electrodynamics of dyons is constructed. Besides the two vector potentials, this manifestly duality invariant formulation involves four additional potentials, scalar potentials which appear as Lagrange multipliers for the electric and magnetic Gauss constraints and potentials for the longitudinal electric and magnetic fields. In this framework, a static dyon appears as a Coulomb-like solution without string singularities. Dirac strings are needed only for the Lorentz force law, not for Maxwell's equations. The magnetic charge no longer appears as a topological conservation law but as a surface integral on a par with electric charge. The theory is generalized to curved space. As in flat space, the string singularities of dyonic black holes are resolved. As a consequence all singularities are protected by the horizon and the thermodynamics is shown to follow from standard arguments in the grand canonical ensemble.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, June 4, 2008 at 10:30

Visit the website.

Place:  Leuven, Celestijnenlaan 200
Time:   Wednesday, May 28, 2008

We would like to announce the general scientific meeting 2008 of the Belgian Physical Society, a conference organised by the Belgian Physical Society and the Université Libre de Bruxelles.

Place:  ULB, Campus Plaine
Time:   Wednesday, May 21, 2008

I will introduce the idea of the Master Space and I will explain how it is possible to extract from it a lot of informations related to the Moduli Space of a class of N=1 supersymmetric gauge theories.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, May 14, 2008 at 13:00

Firstly, we give a short review on most of what is known about background-independence in topological string theory (wavefunction interpretation). Secondly, we discuss this topic in the context of large N dualities. All the results suggest that there should be a underlying (unknown, background independent) integrable structure behind the (known, background dependent) worldsheet formulation of topological string theory, and that this structure is even independent on the side (open or closed) where we are located in the large N duality.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, May 14, 2008 at 10:30

I will review the duality covariant construction of gauged supergravities and some of their applications. In particular, I will discuss the resulting tensor hierarchies and the role of theories with local scale invariance

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, May 7, 2008 at 13:00

Stable and meta-stable vacua in supersymmetric QCD are discussed. The embedding of SQCD on intersecting branes in string theory provides a useful guide for many intricate phenomena. The perturbative brane dynamics involves simple classical interactions between branes, correctly predicting the one-loop and two-loop results in the gauge theory.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, May 7, 2008 at 10:30

E11 is an infinite dimensional Kac-Moody algebra which has been conjectured to be a symmetry of M-theory. We show that the non-linear realisation of the E11 symmetry provides a unified description of all maximal massless and massive supergravities in any dimension. It follows that all the gaugings of maximal supergravities possess an eleven dimensional origin within the E11 formulation of M-theory. We show that E11 introduces a generalised geometry which plays a crucial role in the gauging.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, April 30, 2008 at 13:00

We present some new perspectives on N=1 gauge theories, especially SQCD, D-Brane Quiver Theories and the MSSM, from the stand-point of recent advances in computational and algorithmic algebraic geometry and commutative algebra. We introduce the plethystic program which systematically count gauge invariants and encodes certain hidden symmetries. Moreover, we discuss special structures of the vacuum moduli space, such as that of SQCD being Calabi-Yau.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, April 30, 2008 at 10:30

I review recent lattice results for SU(N) gauge theories in the large N limit. In particular, I focus on the glueball mass spectrum, the topological susceptibility, the critical deconfinement temperature and the quenched meson spectrum. show that for those observables a smooth large N limit exists and that the first expected correction in the 1/N2 expansion accounts for deviations from that limit at finite N all the way down to N=3 (often including also the N=2 case). The problem of the numerical determination of k-string ratio will also be reviewed. Finally, in the last part of the talk, I will discuss some numerical evidence for orientifold planar equivalence.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, April 23, 2008 at 13:00

In this talk, I will elaborate on the form of brany supergravity solutions. These include black holes and D-branes, but also cosmological and other time-dependent configurations. The focus will be on dilaton-p-form systems coupled to gravity in an arbitrary number of dimensions. In particular, I will discuss the intruiging fact that even non-extremal and time-dependent solutions allow a first order formalism that is reminiscent of supersymmetry.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, April 23, 2008 at 10:30

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:    Wednesday, April 16, 2008 at 13:00

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, April 16, 2008 at 10:30

I will review the recent progress made in the study of black strings in AdS5, and show that large black strings are dual to stationary solutions of a fluid dynamics theory on the boundary. The analysis of the resulting Navier-Stokes equations allows us to study the properties of these black strings, and to draw some conclusions on the phases of black holes in AdS5.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, April 9, 2008 at 13:00

Thirty years ago, Matsui and Satz proposed the J/. destruction as a signal of a Quark Gluon Plasma (QGP) formation, due to the Debye screening between the pair c-cbar. At the light of the recent experimental data, I review the different effects on J/Ψ production, from SPS to LHC energies, taking into account both Cold Nuclear Matter (CNM) and QGP effects. Different possibilities and explanations for the available experimental data are discussed. Different model predictions for the arriving LHC data are also presented

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, April 9, 2008 at 10:30

By studying the BPS equations for electrostatic and spherically symmetric configurations in N=2, d=5 gauged supergravity with vector multiplets and hypermultiplets coupled, we demonstrate that no regular supersymmetric black-hole solutions of this kind exist. Furthermore, we demonstrate that it is not possible to construct supersymmetric regular solitons that have the above symmetries. As a consequence the scalar flow associated to the BPS solutions is always unbounded.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, March 19, 2008 at 13:00

We consider a mirror dual of the Berkovits-Vafa A-model for the BPS superstring on AdS5× S5 in the form of a deformed superconifold. Via geometric transition the theory has a dual description in terms of a gaussian matrix model. By applying an observation by Eynard-Marino-Orantin on the holomorphic anomaly equations, we show that the BPS amplitudes of specific AdS4 branes breaking the superconformal symmetry as U(2,2|4)→ Osp(4|4) reproduce the Drukker-Gross circular 1/2-BPS Wilson loops in N=4 SYM.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, March 19, 2008 at 10:30

Intersecting D6-branes provide a suitable framework to derive phenomenologically appealing low-energy spectra and perform computations of couplings including perturbative and non-perturbative corrections. After an introduction into model building from D6-branes at angles in Type IIA orientifold models, the current status on chiral supersymmetric standard model like spectra, in particular on Z6 and Z6', is discussed together with results on non-chiral spectra and couplings.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, March 12, 2008 at 13:00

Combining Seiberg duality in N=1 SQCD with planar equivalence between SQCD and a non-supersymmetric QCD-like orientifold daughter (OQCD) we argue for a non-supersymmetric Seiberg duality. We make a precise proposal for this duality beyond the planar limit and consider its implications for the strongly coupled IR dynamics of OQCD- for example, we get the exact range of the conformal window.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, March 12, 2008 at 10:30

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, March 5, 2008 at 13:00

Most IIB orientifold vacua that have been extensively studied are either toroidal models, which have atypically simple topologies; or so-called "local" models, where global constraints are neglected. However, tools for analyzing IIB vacua non-trivial Calabi- Yau orientifolds are lacking. I will present new techniques for systematically analyzing such setups. These techniques bridge a long-standing mismatch between IIB D7-brane compactifications down to four dimensions and F-theory on Calabi-Yau fourfolds. By studying Sen's limit in detail, we will see that D7 branes in orientifolds have a singularity structure, which is at the origin of this apparent mismatch. Finally, I will show how these results follow naturally from the D9 anti-D9 tachyon condensation picture.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, March 5, 2008 at 10:30

Extended Kac-Moody algebras like E10 and E11 give us important information about supergravity theories, like which deformations or flux parameters in the supergravity theory are allowed. They also teach us something about space-filling branes in string theory. We will review our present understanding of what can be learnt from this Kac-Mody approach and what not.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, February 27, 2008 at 13:00

In the context of AdS/CFT correspondence with fewer degrees of supersymmetry, we study the conformal and finiteness properties of the beta-deformed SU(N) supersymmetric Yang-Mills theories obtained as marginal deformations of N=4 SYM theory with a complex deformation parameter \beta both in the planar and non-planar limit

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, February 27, 2008 at 10:30

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, February 20, 2008 at 13:00

We use the Cremmer-Julia E7 non-linear symmetry of N=8 Supergravity to derive its order κ2 on-shell Hamiltonian in terms of one chiral light-cone superfield. By requiring that E7 commute with the super-Poincaré group, we deduce to lowest non-trivial order in κ, the light cone E7 transformations of all fields of the theory, including the graviton. We then derive the dynamical supersymmetry transformation to order κ2, and express the Hamiltonian as a quadratic form in the chiral superfield. We then extend the internal symmetry to a non-linear realization of E8 again represented on the same superfield.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, February 20, 2008 at 10:30

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, February 13, 2008 at 13:00

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, February 13, 2008 at 10:30

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, February 6, 2008 at 13:00

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, February 6, 2008 at 10:30

We consider correlators of N=4 super Yang Mills of the form A ~ , where the operators O_1 and O_2 are scalar primaries. In particular, we analyze this correlator in the planar limit and in a Lorentzian regime corresponding to high energy interactions in AdS. The planar amplitude is dominated by a Regge pole whose nature varies as a function of the 't Hooft coupling g^2. At large g, the pole corresponds to graviton exchange in AdS whereas, at weak g, the pole is that of the hard perturbative BFKL pomeron. We concentrate on the weak coupling regime and analyze pomeron exchange directly in position space. The analysis relies heavily on the conformal symmetry of the transverse space E^2 and of its holographic dual hyperbolic space H_3, describing with an unified language, both the weak and strong 't Hooft coupling regimes. In particular, the form of the impact factors is highly constrained in position space by conformal invariance. Finally, the analysis suggests a possible AdS eikonal resummation of multi- pomeron exchanges implementing AdS unitarity, which differs from the usual 4-dimensional eikonal exponentiation. We touch on the relations to violations of 4-dimensional unitarity at high energy and to the onset of nonlinear effects and gluon saturation.

Place:  Leuven, Celestijnenlaan 200D 06.32
Time:   Wednesday, January 30, 2008 at 13:00

Metastable vacua with dynamical breaking of supersymmetry has been shown to exist in N=1 SQCD with massive flavours. I will review this issue and I will discuss the existence of such vacua in N=1 gauge theories with adjoint fields and with several gauge groups. These models can be embedded in string theory. Moreover I will show how they can fit in a gauge mediation scenario.

Place:  VUB/ULB, Campus Plaine, building NO, 9th floor, 2.NO.906
Time:   Wednesday, December 19, 2007 at 10:30

I will present recent results showing that E(7) is very likely to be a part of a manifest symmetry group of an extension of d = 11 supergravity, from which the ordinary d = 11 supergravity can be constructed by a truncation. To construct this theory, I will start with a short introduction to the procedure pioneered by Borisov and Ogievetsky in 1974, to construct general relativity in an arbitrary dimension by demanding simultaneous covariance with respect to linear diffeomorphisms and conformal diffeomorphisms alone. Then, I will apply this procedure to E(7) and an adequate generalization of conformal transformations. I will conclude with the implications of this result to higher curvature corrections and some remarks concerning higher symmetry groups such as E(8), E(9), E(10) and E(11).

Place:  Leuven, Celestijnenlaan 200D 06.32
Time:   Wednesday, December 12, 2007 at 13:00

In the main part of my talk I will extend the Penrose limit associated to a metric background and a null geodesic to a covariant expansion of the background around the geodesic using null Fermi coordinates. I will then show the one-to-one correspondence to an expansion of the string embedding variables provided one is working in the light-cone gauge. The advantageous features of this prescription will be discussed using simple examples. In the second part I will present some work in progress regarding the non-perturbative matrix string description of string theory in singular plane wave backgrounds which arise naturally as the Penrose limits of various time-dependent singular spacetimes.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, December 12, 2007 at 10:30

In some situations higher derivative interactions modify the leading order physics significantly. For a class of black holes in string theory the important terms are singled out by anomalies and supersymmetry. Quantitative computations are possible using the explicit supersymmetric Lagrangian. In some cases the higher derivative corrections resolve singularities in the leading order result in a controlled manner.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, December 5, 2007 at 13:00

I will describe the conditions for having no-scale supersymmetry breaking solutions of type II supergravity compactified on manifolds of SU(3)-structure. The supersymmetry is spontaneously broken by the intrinsic torsion of the internal space. I will illustrate the results with concrete examples based on twisted tori. Finally, I will discuss the geometrically induced mu terms and soft terms in the worldvolume of D5, D6 and D9-branes.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, December 5, 2007 at 10:30

I will review recent progress in studying mesons within gauge/gravity duality, in the context of adding flavour degrees of freedom to the AdS/CFT correspondence. Particular emphasis will be given to the spectrum of "mesinos", which are the fermionic superpartners of mesons, and heavy-light mesons, which consist of a heavy and a light quark. The talk is partially based on the review article Mesons in Gauge/Gravity Duals to appear this week.

Place:  Leuven, Celestijnenlaan 200D 05.11
Time:   Wednesday, November 28, 2007 at 13:00

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, November 28, 2007 at 10:30

The addition of supersymmetric backreacting D7-branes to the Type IIB Klebanov-Strassler background allows the study of the dual field theory with an arbitrary number of fundamental flavor fields. We find a supergravity + D7-branes solution and identify the field theory dual, whose RG flow is described by a cascade of Seiberg dualities. We provide several checks of the duality, including beta functions and R-anomalies. A careful study of the cascade is presented.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, November 21, 2007 at 13:00

I will concentrate on a particular aspect of the AdS/CFT correspondence and its extensions, the Physics of flavor degrees of freedom, how the String theory reproduces it and predicts results for interesting observables.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, November 21, 2007 at 10:30

In anti-de Sitter spacetime, massless representations of arbitrary spin can be described either \'a la Vasiliev using master fields, or \'a la Flato-Fronsdal using two-singleton composites. Respectively, these are two-sided and one-sided modules of the underlying higher-spin algebra. Here we construct a map between these two descriptions. The map can be formulated at the level of complex representations, and restricted to different real forms corresponding to models that admit AdS(D), S(D), dS(D), H(D) solutions. We give the decomposition of the direct product of a singleton and a anti-singleton in terms of finite-dimensional representations of $O(D+1)$, and relate this decomposition to the level decomposition of the adjoint representation of the higher-spin algebra.

Place:  Leuven, Celestijnenlaan 200D 05.11
Time:   Wednesday, November 14, 2007 at 13:00

In perturbative calculations in N=8 supergravity, higher loop amplitudes are obtained by combining tree amplitudes and studying unitarity cuts. This talk concerns tree amplitudes and the recursion relations which are far more efficient than Feynman diagrams for computing trees. The relation between tree amplitudes in gravity and gauge theories and SUSY Ward identities for these amplitudes are also major themes.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, November 14, 2007 at 10:30

Recently, Witten has proposed, based on an analysis of pure gravity in AdS3, that a family of extremal self-dual meromorphic bosonic conformal field theories at c=24 k (with k=1,2,...) exists. As I shall show, the partition functions of these theories satisfy a modular differential equation whose order is asymptotically proportional to \sqrt{k}. According to the general analysis of Zhu (that I shall review) this then suggests that the vacuum representation of these theories should have a null-vector at twice the order of the differential equation. Given the structure of the proposed extremal CFTs, one finds a contradiction for the theories with k\geq 42.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, November 7, 2007 at 13:00

The singularity theorems tell us that spacetime singularities occur under very general circumstances in general relativity, but they say little about their nature---detailed insights require further analysis of Einstein's field equations. Of particular interest is the structure of generic singularities; this talk will be an overview of our current knowledge about the nature of such singularities in the light of recent analytical and numerical advances. The talk will focus on (i) reviewing and comparing different approaches, with emphasis on motivations and results, (ii) the effects of extreme curvature on asymptotic causal structure, and vice versa, (iii) similarities and differences between spatially homogeneous and inhomogeneous models.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, November 7, 2007 at 10:30

A possible five dimensional string set-up dual to QCD is presented, with a discussion of the known informations about the perturbative and non-perturbative spectrum. It is then shown how gravity in five dimensions captures some features of the Quark Gluon Plasma produced at RHIC. Finally, the results from ten dimensional models are reported.

Place:  Leuven, Celestijnenlaan 200D 05.11
Time:   Wednesday, October 31, 2007 at 13:00

To every supersymmetric supergravity background one can associate a Lie superalgebra, called its Killing superalgebra because it is made out of Killing spinors and Killing vectors. (A classical riemannian geometric version of this construction gives rise to exceptional Lie algebras starting from spheres.) In this talk I will review the construction of the Killing superalgebra and discuss some applications as well as some extensions. The talk will be based on the following eprints hep-th/9902066, hep-th/0409170, hep-th/0703192, 0706.2600, 0706.2829 and 0708.3738, as well as work in progress.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, October 31, 2007 at 10:30

I will review how the gravitino in 11-dimensional supergravity is described by a 320-dimensional vector-spinor representation of K(E10), the maximal compact subalgebra of the hyperbolic Kac-Moody algebra E10. By restriction to the affine subalgebra E9, the decomposition of the vector-spinor also gives the K(E9) transformations of the fermions in two-dimensional N=16 supergravity. I will present new results about the ideals of K(E9), associated to these unfaithful representations, which might be useful as a step towards a faithful representation of K (E10). Based mainly on hep-th/0611314, and work in progress.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, October 24, 2007 at 13:00

We construct interpolating solutions describing single-center static extremal non-supersymmetric black holes in four-dimensional N=2 supergravity theories with cubic prepotentials. To this end, we derive and solve first-order flow equations for rotating electrically charged extremal black holes in a Taub-NUT geometry in five dimensions. We then use the connection between five- and four-dimensional extremal black holes to obtain four-dimensional flow equations and we give the corresponding solutions. Based on arXiv:0706.3373

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, October 24, 2007 at 10:30

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Friday, October 19, 2007, 16:00-17:00

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Thursday, October 18, 2007, 16:00-18:00

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, October 17, 2007, 17:00-18:00

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, October 17, 2007, 16:00-17:00

Place:   Leuven, Celestijnenlaan 200D 05.11
Time:    Wednesday, October 17, 2007 at 13:00

The phase structure of Kaluza-Klein black holes is briefly reviewed. Then attention is turned to stationary solutions in higher-dimensional gravity. In particular, the construction of an approximate solution for an asymptotically flat, neutral, thin rotating black ring in any dimension higher than four is discussed. By exploiting the correspondence between ultra-spinning black holes and black membranes on a two-torus, we take steps towards qualitatively completing the phase diagram of rotating blackfolds with a single angular momentum. This includes connections between Myers-Perry black holes and black rings as well as black Saturns, through merger transitions involving `pinched' black holes.

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, October 17, 2007 at 10:30

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Tuesday, October 16, 2007, 17:00-18:00

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Tuesday, October 16, 2007, 16:00-17:00

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Monday, October 15, 2007, 17:00-18:00

Programme

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Monday, October 15, 2007, 16:00-17:00

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, October 10, 2007 at 13:00

In a Hamiltonian treatment the equations of (maximal) supergravity split into two sets of equations: dynamical equations and constraint equations. For the dynamical equations it has been known for some time that there is an interesting link between solutions to the dynamical equations and geodesics on a symmetric space based on the Kac-Moody algebra E10. In this talk the constraint equations will be analysed in detail and it will be shown how and that they fit the geodesic picture for supergravity evolution. At the same time they give a hint of an extension of the known Sugawara construction of E9 to E10.

Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
Time:   Wednesday, October 10, 2007 at 10:30

website

Time:   Wednesday, October 3, 2007

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, September 26, 2007 at 13:00

Place:  Leuven, Celestijnenlaan 200D 06.34
Time:   Wednesday, September 26, 2007 at 10:30

 

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