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S. Ferrara

Publications and source records attributed to S. Ferrara.

At least 127 records · Page 7Linked to original sources
arXiv1998

N=6 Supergravity on $AdS_5$ and the $SU(2,2/3)$ Superconformal Correspondence

It is argued that N=6 supergravity on $AdS_5$, with gauge group $SU(3)\times U(1)$ corresponds, at the classical level, to a subsector of the ``chiral'' primary operators of N=4 Yang-Mills theories. This projection involves a ``duality transformation'' of N=4 Yang-Mills theory and therefore can be valid if the coupling is at a self-dual point, or for those amplitudes that do not depend on the coupling constant.

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arXiv1998

Bulk Gauge Fields in AdS Supergravity and Supersingletons

We describe conformal operators living at the boundary of $AdS_{d+1}$ in a general setting. Primary conformal operators at the threshold of the unitarity bounds of UIR's of O(d,2) correspond to singletons and massless fields in $AdS_{d+1}$, respectively. For maximal supersymmetric theories in $AdS_{d+1}$ we describe ``chiral'' primary short supermultiplets and non-chiral primary long supermultiplets. Examples are exhibited which correspond to KK and string states. We give the general contribution of a primary conformal operator to the OPE and Green's functions of primary fields, which may be relevant to compute string corrections to the four-point supergraviton amplitude in Anti-de-Sitter space. The material in this paper was presented by one of the authors (S.F) at String 98, Santa Barbara.

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arXiv1998

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

We show that $p$-forms on $AdS_{2p+1}$ describe both singletons and massless particles. On the $2p$-dimensional boundary the singleton $p$-form Lagrangian reduces to the conformally invariant functional $\int F^2$. 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 AdS$_5$ and AdS$_7$ supergravity respectively.

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arXiv1998

AdS_6 Interpretation of 5d Superconformal Field Theories

We explore the connection of anti-de-Sitter supergravity in six dimensions, based on the exceptional F(4) superalgebra, and its boundary superconformal singleton theory. The interpretation of these results in terms of a D4-D8 system and its near horizon geometry is suggested.

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arXiv1998

N=1,2 4D Superconformal Field Theories and Supergravity in $AdS_5$

We consider D3 branes world-volume theories substaining $N=1,2$ superconformal field theories. Under the assumption that these theories are dual to $N=2,4$ supergravities in $AdS_5$, we explore the general structure of the latter and discuss some issues when comparing the bulk theory to the boundary singleton theory.

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arXiv1998

G/H M-branes and AdS_{p+2} Geometries

We prove the existence of a new class of BPS saturated M-branes. They are in one-to-one correspondence with the Freund--Rubin compactifications of M-theory on either (AdS_4) x (G/H) or (AdS_7) x (G/H), where G/H is the seven (or four) dimensional Einstein coset manifolds classified long ago in the context of Kaluza Klein supergravity. The G/H M-branes are solitons that interpolate between flat space at infinity and the old Kaluza-Klein compactifications at the horizon. They preserve N/2 supersymmetries where N is the number of Killing spinors of the (AdS) x (G/H) vacuum. A crucial ingredient in our discussion is the identification of a solvable Lie algebra parametrization of the Lorentzian non compact coset SO(2,p+1)/SO(1,p+1) corresponding to anti de Sitter space AdS_{p+2} . The solvable coordinates are those naturally emerging from the near horizon limit of the G/H p-brane and correspond to the Bertotti Robinson form of the anti-de-Sitter metric. The pull-back of anti-de-Sitter isometries on the p-brane world-volume contain, in particular, the broken conformal transformations recently found in the literature.

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arXiv1998

Membranes and Fivebranes with Lower Supersymmetry and their AdS Supergravity Duals

We consider superconformal field theories in three and six dimensions with eight supercharges which can be realized on the world-volume of M-theory branes sitting at orbifold singularities. We find that they should admit a N=4 and N=2 supergravity dual in AdS_4 and AdS_7, respectively. We discuss the characteristics of the corresponding gauged supergravities.

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arXiv1998

Gauge fields as composite boundary excitations

We investigate representations of the conformal group that describe "massless" particles in the interior and at the boundary of anti-de Sitter space. It turns out that massless gauge excitations in anti-de Sitter are gauge "current" operators at the boundary. Conversely, massless excitations at the boundary are topological singletons in the interior. These representations lie at the threshold of two "unitary bounds" that apply to any conformally invariant field theory. Gravity and Yang-Mills gauge symmetry in anti-De Sitter is translated to global translational symmetry and continuous $R$-symmetry of the boundary superconformal field theory.

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arXiv1998

Horizon Geometry, Duality and Fixed scalars in Six Dimensions

We consider the problem of extremizing the tension for BPS strings in D=6 supergravities with different number of supersymmetries. General formulae for fixed scalars and a discussion of degenerate directions is given. Quantized moduli, according to recent analysis, are supposed to be related to conformal field theories which are the boundary of three dimensional anti-de Sitter space time.

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arXiv1998

Conformal Maxwell theory as a singleton field theory on AdS_5, IIB three-branes and duality

We examine the boundary conditions associated with extended supersymmetric Maxwell theory in 5-dimensional anti-De Sitter space. Excitations on the boundary are identical to those of ordinary 4-dimensional conformal invariant super electrodynammics. Extrapolations of these excitations give rise to a 5-dimensional topological gauge theory of the singleton type. The possibility of a connection of this phenomenon to the world volume theory of 3-branes in IIB string theory is discussed.

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arXiv1998

U-Duality and Central Charges in Various Dimensions Revisited

A geometric formulation which describes extended supergravities in any dimension in presence of electric and magnetic sources is presented. In this framework the underlying duality symmetries of the theories are manifest. Particular emphasis is given to the construction of central and matter charges and to the symplectic structure of all D=4, N-extended theories. The latter may be traced back to the existence, for N>2, of a flat symplectic bundle which is the N>2 generalization of N=2 Special Geometry.

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arXiv1998

BPS black holes, supersymmetry and orbits of exceptional groups

We report on duality invariant constraints, which allow a classification of BPS black holes preserving different fractions of supersymmetry. We then relate this analysis to the orbits of the exceptional groups $E_{6(6)}, E_{7(7)}$, relevant for black holes in five and four dimensions.

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arXiv1997

Central Extensions of Supersymmetry in Four and Three Dimensions

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.

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arXiv1997

Tensor and Vector Multiplets in Six-Dimensional Supergravity

We construct the complete coupling of $(1,0)$ supergravity in six dimensions to $n$ tensor multiplets, extending previous results to all orders in the fermi fields. We then add couplings to vector multiplets, as dictated by the generalized Green-Schwarz mechanism. The resulting theory embodies factorized gauge and supersymmetry anomalies, to be disposed of by fermion loops, and is determined by corresponding Wess-Zumino consistency conditions, aside from a quartic coupling for the gaugini. The supersymmetry algebra contains a corresponding extension that plays a crucial role for the consistency of the construction. We leave aside gravitational and mixed anomalies, that would only contribute to higher-derivative couplings.

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arXiv1997

R^4 Couplings in M and Type II Theories

We discuss several implications of R^4 couplings in M theory when compactified on Calabi-Yau (CY) manifolds. In particular, these couplings can be predicted by supersymmetry from the mixed gauge-gravitational Chern-Simons couplings in five dimensions and are related to the one-loop holomorphic anomaly in four-dimensional N=2 theories. We find a new contribution to the Einstein term in five dimensions proportional to the Euler number of the internal CY threefold, which corresponds to a one-loop correction of the hypermultiplet geometry. This correction is reproduced by a direct computation in type II string theories. Finally, we discuss a universal non-perturbative correction to the type IIB hyper-metric.

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arXiv1997

Duality, Central Charges and Entropy of Extremal BPS Black Holes

We report on some general results on the physics of extremal BPS black holes in four and five dimensions. The duality-invariant entropy-formula for all $N>2$ extended supergravities is derived. Its relation with the fixed-scalar condition for the black-hole ``potential energy'' wich extremizes the BPS mass is obtained. BPS black holes preserving different fractions of supersymmetry are classified in a U-duality invariant set up. The latter deals with different orbits of the fundamental representations of the exceptional groups $E_{7(7)}$ and $E_{6(6)}$. We comment upon the interpretation of these results in a string and M-theory framework.

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arXiv1997

Flat Symplectic Bundles of N-Extended Supergravities, Central Charges and Black-Hole Entropy

In these lectures we give a geometrical formulation of N-extended supergravities which generalizes N=2 special geometry of N=2 theories. In all these theories duality symmetries are related to the notion of "flat symplectic bundles" and central charges may be defined as "sections" over these bundles. Attractor points giving rise to "fixed scalars" of the horizon geometry and Bekenstein-Hawking entropy formula for extremal black-holes are discussed in some details.

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