Search

This is an overview for non-specialists of some of the progress in research on black holes in String and Supergravity theories, mostly focused on the search and study of explicit classical solutions describing them. [ABSTRACT FROM AUTHOR]

We outline the solution of the Killing spinor equations of the heterotic supergravity. In addition, we describe the classification of all half supersymmetric solutions. [ABSTRACT FROM AUTHOR]

We first review the notion of a G2—manifold, defined in terms of a principal G2 (“gauge”) bundle over a 7—dimensional manifold, before discussing their relation to supergravity. In a second thread, we focus on associative submanifolds and present their deformation theory. In particular, we elaborate on a deformation problem with coassociative boundary condition. Its space of infinitesimal deformations can be identified with the solution space of an elliptic equation whose index is given by a topological formula. [ABSTRACT FROM AUTHOR]

The spinorial geometry method is an effective method for constructing systematic classifications of supersymmetric supergravity solutions. Recent work on analysing highly supersymmetric solutions in type IIB supergravity using this method is reviewed [1, 2]. It is shown that all supersymmetric solutions of IIB supergravity with more than 28 Killing spinors are locally maximally supersymmetric. [ABSTRACT FROM AUTHOR]

We study the E7(7) on-shell duality symmetry of N = 8 supergravity in four dimensions and show that all physical fields transform under E7(7) on the light-cone. We then use this symmetry to construct order κ2 interactions in light-cone superspace, by requiring this E7(7) transformations commutes with the supersymmetry transformations. [ABSTRACT FROM AUTHOR]

We study string theory duals of the expanding boost invariant conformal gauge theory plasmas at strong coupling. The dual supergravity background is constructed as an asymptotic late-time expansion, corresponding to equilibration of the gauge theory plasma. The absence of curvature singularities in the first few orders of the late-time expansion of the dual gravitational background unambiguously determines the equilibrium equation of the state, and the shear viscosity of the gauge theory plasma. While the absence of the leading pole singularities in the gravitational curvature invariants at the third order in late-time expansion determines the relaxation time of the plasma, the subleading logarithmic singularity can not be canceled within a supergravity approximation. We comment on the possible interpretations of this singularity. [ABSTRACT FROM AUTHOR]

We show that the exisiting supergravity theories in ten dimensions can be extended with extra gauge fields whose rank is equal to the spacetime dimension. These gauge fields have vanishing field strength but nevertheless play an important role in the coupling of supergravity to spacetime filling branes. We discuss the role of these gauge fields in the construction of string theories with sixteen supercharges and mention their relation with a conjectured hyperbolic symmetry underlying string theory and M theory. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We use the canonical quantization of N = 1 supergravity for the case of Gowdy T3 cosmological models. We show the existence of physical states for these models, and obtain the wave function of the Universe. We also analyze the behavior of the wave function of the universe near the classical curvature singularity of these models. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We discuss the ro⁁le of enlarged superspaces in two seemingly different contexts, the structure of the p-brane actions and that of the Cremmer-Julia-Scherk eleven-dimensional supergravity. Both provide examples of a common principle: the existence of an enlarged superspaces coordinates/fields correspondence by which all the (worldvolume or spacetime) fields of the theory are associated to coordinates of enlarged superspaces. In the context of p-branes, enlarged superspaces may be used to construct manifestly supersymmetry-invariant Wess-Zumino terms and as a way of expressing the Born-Infeld worldvolume fields of D-branes and the worldvolume M5-brane two-form in terms of fields associated to the coordinates of these enlarged superspaces. This is tantamount to saying that the Born-Infeld fields have a superspace origin, as do the other worldvolume fields, and that they have a composite structure. In D=11 supergravity theory enlarged superspaces arise when its underlying gauge structure is investigated and, as a result, the composite nature of the A3 field is revealed: there is a full one-parametric family of enlarged superspace groups that solve the problem of expressing A3 in terms of spacetime fields associated to their coordinates. The corresponding enlarged supersymmetry algebras turn out to be deformations of an expansion of the osp(1|32) algebra. The unifying mathematical structure underlying all these facts is the cohomology of the supersymmetry algebras involved. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We review briefly the notion of BPS preons, first introduced in 11-dimensional context as hypothetical constituents of M-theory, in its generalization to arbitrary dimensions and emphasizing the relation with twistor approach. In particular, the use of a “twistor-like” definition of BPS preon (almost) allows us to remove supersymmetry arguments from the discussion of the relation of the preons with higher spin theories and also of the treatment of BPS preons as constituents. We turn to the supersymmetry in the second part of this contribution, where we complete the algebraic discussion with supersymmetric arguments based on the M-algebra (generalized Poincaré superalgebra), discuss the possible generalization of BPS preons related to the osp(1|n) (generalized AdS) superalgebra, review a twistor-like κ-symmetric superparticle in tensorial superspace, which provides a point-like dynamical model for BPS preon, and the ro⁁le of BPS preons in the analysis of supergravity solutions. Finally we describe resent results on the concise superfield description of the higher spin field equations and on superfield supergravity in tensorial superspaces. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In order to fix the moduli, non-trivial fluxes might the essential input. We summarize different aspects of compactifications in the presence of fluxes, as there is the relation to generalized Scherk-Schwarz reductions and gauged supergravity but also the description of flux-deformed geometries in terms of G-structures and intrinsic torsion. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We review some properties of N=8 gauged supergravity in four dimensions with modified, but AdS invariant boundary conditions on the m2 = -2 scalars. There is a one-parameter class of asymptotic conditions on these fields and the metric components, for which the full AdS symmetry group is preserved. The generators of the asymptotic symmetries are finite, but acquire a contribution from the scalar fields. For a large class of such boundary conditions, we find there exist black holes with scalar hair that are specified by a single conserved charge. Since Schwarschild-AdS is a solution too for all boundary conditions, this provides an example of black hole non-uniqueness. We also show there exist solutions where smooth initial data evolve to a big crunch singularity. This opens up the possibility of using the dual conformal field theory to obtain a fully quantum description of the cosmological singularity, and we report on a preliminary study of this. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

General relativity can be formulated as a SU(2) BF-theory with constraints, as shown by Plebanski [4]. Jacobson has given a SL(2, C) invariant fermionic extension of it, from which supergravity turns out [6]. We present a supersymmetric, Sp(2|1) invariant extension of the theory of Plebanski. Consistency requires that the constraints are properly generalized, resulting as well the action of supergravity. [ABSTRACT FROM AUTHOR]