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A. Zaffaroni

Publications and source records attributed to A. Zaffaroni.

At least 37 records · Page 2Linked to original sources
arXiv2000

A Note on the Holographic Beta and C Functions

The holographic RG flow in AdS/CFT correspondence naturally defines a holographic scheme in which the central charge c and the beta function are related by a universal formula. We perform some checks of that formula and we compare it with quantum field theory expectations. We discuss alternative definitions of the c-function. In particular, we compare, for a particular supersymmetric flow, the holographic c-function with the central charge computed directly from the two-point function of the stress-energy tensor.

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arXiv2000

The Holographic RG flow to conformal and non-conformal theory

We review some aspects of the AdS supergravity description of RG flows. The case of a flow to an IR CFT can be rigorously studied within the framework of supergravity. Here we discuss various central charges of the conformal theory (included the usually neglected ones) and we compare them with QFT expectations. The case of flows to non-conformal theories is more problematic in that one usually encounters a naked singularity. We mainly focus on the flow to an IR N=1 super Yang-Mills theory. We discuss the properties of the solution and we briefly comment on the fate of the singularity. We also compare the supergravity results with the expectations of an N=1 SYM at strong coupling.

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arXiv1999

The Supergravity Dual of N=1 Super Yang-Mills Theory

We find an exact, N=1 supersymmetric kink solution of 5d gauged supergravity. We associate this solution with the RG flow from N=4 super Yang-Mills theory, deformed by a relevant operator, to pure N=1 super Yang-Mills in the IR. We test this identification by computing various QFT quantities using the supergravity dual: the tension of electric and magnetic strings and the gaugino condensate. As demanded by our identification, our kink solution is a true deformation of N=4, that exhibits confinement of quarks, magnetic screening, and spontaneous chiral symmetry breaking.

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arXiv1999

Confinement and Condensates Without Fine Tuning in Supergravity Duals of Gauge Theories

We discuss a solution of the equations of motion of five-dimensional gauged type IIB supergravity that describes confining SU(N) gauge theories at large N and large 't Hooft parameter. We prove confinement by computing the Wilson loop, and we show that our solution is generic, independent of most of the details of the theory. In particular, the Einstein-frame metric near its singularity, and the condensates of scalar, composite operators are universal. Also universal is the discreteness of the glueball mass spectrum and the existence of a mass gap. The metric is also identical to a generically confining solution recently found in type 0B theory.

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arXiv1999

Novel Local CFT and Exact Results on Perturbations of N=4 Super Yang Mills from AdS Dynamics

We find new, local, non-supersymmetric conformal field theories obtained by relevant deformations of the N=4 super Yang Mills theory in the large $N$ limit. We contruct interpolating supergravity solutions that naturally represent the flow from the N=4 super Yang Mills UV theory to these non-supersymmetric IR fixed points. We also study the linearization around the N=4 superconformal point of N=1 supersymmetric, marginal deformations. We show that they give rise to N=1 superconformal fixed points, as expected from field-theoretical arguments.

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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

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

On the realization of chiral four-dimensional gauge theories using branes

We consider a general brane construction for realizing chiral four-dimensional gauge theories. The advantage of the construction is the simplicity and the possibility of realizing a large class of models existing in the literature. We start the study of these models by determining the matter content and the superpotential which naturally arise in the brane construction.

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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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arXiv1997

Spontaneously Broken N=2 Supergravity Without Light Mirror Fermions

We present a spontaneously broken N=2 supergravity model that reduces in the flat limit to a globally supersymmetric N=2 system with explicit soft supersymmetry breaking terms. These soft terms generate a mass O(100 GeV) for mirror quarks and leptons, while leaving the physical fermions light, thereby overcoming one of the major obstacles towards the construction of a realistic N=2 model of elementary interactions.

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arXiv1996

M-Theory Origin of Mirror Symmetry in Three Dimensional Gauge Theories

We present M-theory compactifications on $K_3 \times K_3$ with membranes near the $A_n$ or $D_n$ singularities of the $K_3$ spaces. By realizing each of these compactifications in two different ways as type I' models with 2- and 6-branes, we explain the three-dimensional duality between gauge theories recently found by Intriligator and Seiberg. We also find new pairs of dual gauge theories, which we briefly describe.

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arXiv1995

Heterotic-Type II String Duality and the H-Monopole Problem

Since T-duality has been proved only perturbatively and most of the heterotic states map into solitonic, non-perturbative, type II states, the 6-dimensional string-string duality between the heterotic string and the type II string is not sufficient to prove the S-duality of the former, in terms of the known T-duality of the latter. We nevertheless show in detail that perturbative T-duality, together with the heterotic-type II duality, does imply the existence of heterotic H-monopoles, with the correct multiplicity and multiplet structure. This construction is valid at a generic point in the moduli space of heterotic toroidal compactifications.

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arXiv1995

S-Duality in N=4 Yang-Mills Theories

Evidence in favor of $SL(2,Z)$ S-duality in $N=4$ supersymmetric Yang-Mills theories in four dimensions and with general compact, simple gauge groups is presented. (Contribution to the Proceedings of the Strings '95 conference, March 13-18, 1995, USC, and the Proceedings of the Trieste Conference on S-Duality and Mirror Symmetry, June 5-9, 1995.)

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arXiv1994

Non-Abelian Strong-Weak Coupling Duality in (String-Derived) N=4 Supersymmetric Yang-Mills Theories

We study strong-weak coupling duality (S-duality) in N=4 supersymmetric non-Abelian Yang-Mills theories. These theories arise naturally as the low-energy limit of four-dimensional toroidal compactifications of the heterotic string. Firstly, we define the free energy in the presence of electric and magnetic fluxes using 't Hooft's prescription, i.e. through functional integrals at finite volume in the presence of twisted boundary conditions. Then, we compute those free energies in two limiting cases: small and large coupling constant. Finally, we extend the free-energies to all values of the coupling constant (and the theta angle) by presenting a fully S-duality invariant ansatz. This ansatz obeys all relevant consistency conditions; in particular, it obeys 't Hooft duality equations and Witten's magnetic-electric transmutation. The existence of an S-duality invariant, consistent definition of free energies supports the claim made in the literature that S-duality is a duality symmetry of N=4 SUSY Yang-Mills. Our ansatz also suggests that N=4, irrespective of whether partially broken or not, is in a self-dual phase: no phase transitions occur between the strong and weak coupling regimes.

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