12,266 research outputs found

    Superspace Representations of SU(2,2/N) Superalgebras and Multiplet Shortening

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    We derive massless and massive representations of all SU(2,2/N) superalgebras by using superfields defined in "harmonic superspace". This method allows one to easily construct "short superfields" which are relevant in the analysis of the AdS/CFT correspondence.Comment: Talk given at the TMR Conference on Quantum Aspects of Gauge Theories, Supersymmetry and Unification, Paris, 1-7 September 199

    Dualities Compositeness and Spacetime Structure of 4d Extreme Stringy Black Holes

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    We study the BPS black hole solutions of the (truncated) action for heterotic string theory compactified on a six-torus. The O(3,Z) duality symmetry of the theory, together with the bound state interpretation of extreme black holes, is used to generate the whole spectrum of the solutions. The corresponding spacetime structures, written in terms of the string metric, are analyzed in detail. In particular, we show that only the elementary solutions present naked singularities. The bound states have either null singularities (electric solutions) or are regular (magnetic or dyonic solutions) with near-horizon geometries given by the product of two 2d spaces of constant curvature. The behavior of some of these solutions as supersymmetric attractors is discussed. We also show that our approach is very useful to understand some of the puzzling features of charged black hole solutions in string theory.Comment: 17 pages, LaTex, no figure

    Regular R-R and NS-NS BPS black holes

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    We show in a precise group theoretical fashion how the generating solution of regular BPS black holes of N=8 supergravity, which is known to be a solution also of a simpler N=2 STU model truncation, can be characterized as NS-NS or R-R charged according to the way the corresponding STU model is embedded in the original N=8 theory. Of particular interest is the class of embeddings which yield regular BPS black hole solutions carrying only R-R charge and whose microscopic description can possibly be given in terms of bound states of D-branes only. The microscopic interpretation of the bosonic fields in this class of STU models relies on the solvable Lie algebra (SLA) method. In the present article we improve this mathematical technique in order to provide two distinct descriptions for type IIA and type IIB theories and an algebraic characterization of S*T--dual embeddings within the N=8,d=4 theory. This analysis will be applied to the particular example of a four parameter (dilatonic) solution of which both the full macroscopic and microscopic descriptions will be worked out.Comment: latex, 30 pages. Final version to appear on Int.J.Mod.Phy

    Central Extensions of Supersymmetry in Four and Three Dimensions

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    We consider the maximal central extension of the supertranslation algebra in d=4 and 3, which includes tensor central charges associated to topological defects such as domain walls (membranes) and strings. We show that for all N-extended superalgebras these charges are related to nontrivial configurations on the scalar moduli space. For N=2 theories obtained from compactification on Calabi-Yau threefolds, we give an explicit realization of the moduli-dependent charges in terms of wrapped branes.Comment: 11 pages. Sections 2 and 4 expanded, misprints corrected, references adde

    String Quantum Symmetries From Picard-Fuchs Equations And Their Monodromy

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    Local and global properties of the moduli space of Calabi--Yau type compactifications determine the low energy parameters of the string effective action. We show that the moduli space geometry is entirely encoded in the Picard--Fuchs equations for the periods of the Calabi--Yau H(3)H^{(3)}--cohomology.Comment: 33 pages, plain TeX, CERN-TH.6777/93,POLFIS-TH.24/9

    Dyonic Masses from Conformal Field Strengths in D even Dimensions

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    We show that D/2--form gauge fields in D even dimensions can get a mass with both electric and magnetic contributions when coupled to conformal field--strengths whose gauge potentials is are \frac {D-2}{2}- forms. Denoting by e^I_\L and m^{I\L} the electric and magnetic couplings, gauge invariance requires: e^I_\L m^{J\L}\mp e^J_\L m^{I\L}=0, where I,\L= 1... m denote the species of gauge potentials of degree D/2 and gauge fields of degree D/2-1, respectively. The minus and plus signs refer to the two different cases D=4n and D=4n+2 respectively and the given constraints are respectively {\rm {Sp}}(2m) and {\rm {O}}(m,m) invariant. For the simplest examples, (I,\L=1 for D=4n and I,\L=1,2 for D=4n+2) both the e,m quantum numbers contribute to the mass \m=\sqrt {e^2 +m^2} . This phenomenon generalizes to DD even dimensions the coupling of massive antisymmetric tensors which appear in D=4 supergravity Lagrangians which derive from flux compactifications in higher dimensions. For D=4 we give the supersymmetric generalization of such couplings using N=1 superspace.Comment: 11 pages, LaTeX source, typos corrected. Version to appear on Phys.Lett.

    Superconformal Field Theories, Multiplet Shortening, and the AdS5_5/SCFT4_4 Correspondence

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    We review the unitarity bounds and the multiplet shortening of UIR's of 4 dimensional superconformal algebras SU(2,2∣N)SU(2,2|N), (N=1,2,4N=1,2,4) in view of their dual role in the AdS/SCFT correspondence. Some applications to KK spectra, non-perturbative states and stringy states are given.Comment: minor changes, references adde

    Gauge Fields and Singletons of AdS2p+1AdS_{2p+1}

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    We show that pp-forms on AdS2p+1AdS_{2p+1} describe both singletons and massless particles. On the 2p2p-dimensional boundary the singleton pp-form Lagrangian reduces to the conformally invariant functional ∫F2\int F^2. All the representations, singletons as well as massless, are zero center modules and involve a vacuum mode. Two- and three-form singleton fields are required by supersymmetry in AdS5_5 and AdS7_7 supergravity respectively.Comment: tex file, 13 page

    Some Pathways in non-Linear Supersymmetry: Special Geometry Born-Infeld's, Cosmology and dualities

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    This review is devoted to some aspects of non-linear Supersymmetry in four dimensions that can be efficiently described via nilpotent superfields, in both rigid and curved Superspace. Our focus is mainly on the partial breaking of rigid N=2N=2 Supersymmetry and on a class of generalized Born-Infeld systems that originate from Special Geometry and on some prototype cosmological models, starting from the Supergravity embedding of Starobinsky inflation. However, as an aside we also review briefly some interesting two-field extensions of the Born-Infeld Lagrangian whose field equations enjoy extended duality symmetries.Comment: Contribution to the Proceedings of "Group Theory, Probability, and the Structure of Spacetime", A Conference on the Occasion of Professor V.S. Varadarajan's Retirement, UCLA Mathematics Department, November 7-9, 2014. To appear in a special issue of "p-Adic Numbers, Ultrametric Analysis and Applications". 35 pages LaTeX, 1 eps figure. Typos corrected, reference adde

    Short representations of SU(2,2/N) and harmonic superspace analyticity

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    We consider the harmonic superspaces associated to SU(2,2/N) superconformal algebras. For arbitrary N, we show that massless representations, other than the chiral ones, correspond to [N/2] ``elementary'' ultrashort analytic superfields whose first component is a scalar in the k antisymmetric irrep of SU(N) (k=1... [N/2]) with top spin Jtop=(N/2−k/2,0)J_{\rm\scriptsize top}= (N/2-k/2,0). For N=2n we analyze UIR's obtained by tensoring the self-conjugate ultrashort multiplet JtopJ_{\rm\scriptsize top}= (n/2,0) and show that N-1 different basic products give rise to all possible UIR's with residual shortening.Comment: references adde
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