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E. Lopez

Publications and source records attributed to E. Lopez.

32 records · Page 2Linked to original sources
arXiv1999

A Family of N=1 SU(N)^k Theories from Branes at Singularities

We obtain N=1 SU(N)^k gauge theories with bifundamental matter and a quartic superpotential as the low energy theory on D3-branes at singular points. These theories generalize that on D3-branes at a conifold point, studied recently by Klebanov and Witten. For k=3 the defining equation of the singular point is that of an isolated D_4 singularity. For k>3 we obtain a family of multimodular singularities. The considered SU(N)^k theories flow in the infrared to a non-trivial fixed point. We analyze the AdS/CFT correspondence for our examples.

hep-th↗
arXiv1998

Duality for SUxSO and SUxSp via Branes

Using a six-orientifold, fourbranes and four fivebranes in type IIA string theory we construct $\mathcal{N}$=1 supersymmetric gauge theories in four dimensions with product group $SU(M)\times SO(N)$ or $SU(M)\times Sp(2N)$, a bifundamental flavor and quarks. We obtain the Seiberg dual for these theories and rederive it via branes. To obtain the complete dual group via branes we have to add semi-infinite fourbranes. We propose that the theory derived from branes has a meson deformation switched on. This deformation implies higgsing in the dual theory. The addition of the semi-infinite fourbranes compensates this effect.

hep-th↗
arXiv1996

$K3$-Fibrations and Softly Broken $N=4$ Supersymmetric Gauge Theories

Global geometry of $K3$-fibration Calabi-Yau threefolds, with Hodge number $h_{2,1}=r+1$, is used to define $N=4$ softly broken $SU(r+1)$ gauge theories, with the bare coupling constant given by the dual heterotic dilaton, and the mass of the adjoint hypermultiplet given by the heterotic string tension. The $U(r+1)$ Donagi-Witten integrable model is also derived from the $K3$-fibration structure, with the extra $U(1)$ associated to the heterotic dilaton. The case of $SU(2)$ gauge group is analyzed in detail. String physics beyond the heterotic point particle limit is partially described by the $N=4$ softly broken theory.

hep-th↗
arXiv1996

Integrability, Jacobians and Calabi-Yau Threefolds

The integrable systems associated with Seiberg-Witten geometry are considered both from the Hitchin-Donagi-Witten gauge model and in terms of intermediate Jacobians of Calabi-Yau threefolds. Dual pairs and enhancement of gauge symmetries are discussed on the basis of a map from the Donagi-Witten ``moduli'' into the moduli of complex structures of the Calabi-Yau threefold.

hep-th↗
arXiv1996

Integrability, Duality and Strings

In these notes evidence is presented for intepreting the moduli space of the integrable model associated to $N\!=\!2$ gauge theories with $N\!=\!4$ matter content, in terms of Calabi-Yau manifolds. We restrict to the case of gauge group $SU(2)$, which is compared with the moduli space of the Calabi-Yau manifold $WP_{11226}^{12}$ appearing in the rank three dual pair $(K^{3}\times T^{2} / WP_{11226}^{12})$. The singularity loci of both spaces are maped in a one to one way and, in the weak coupling limit, $N\!=\!2$ $SU(2)$ pure Yang-Mills is obtained in both cases by the same type of blow up. Comments on the interpretation of the strong coupling locus from the perspective of the integrable system are done.

hep-th↗
arXiv1996

$S$-Duality and the Calabi-Yau Interpretation of the $N = 4$ to $N = 2$ Flow

The action of the $S$-duality $Sl(2,Z)$ group on the moduli of the Calabi-Yau manifold $W\IP^{12}_{11226}$ appearing in the rank two dual pair $(K^{3}\times T^{2}/W\IP^{12}_{11226})$ is defined by interpreting the $N\!=\!4$ to $N\!=\!2$ flow, for $SU(2)$ supersymmetric Yang-Mills, in terms of the Calabi-Yau moduli. The different singularity loci are mapped in a one to one way, and the ($N\!=\!2$ limit/point particle limit) is obtained in both cases by the same type of blow up. Moreover, it is shown that the $S$-duality group permutes the different singularity loci of the moduli of $W\IP^{12}_{11226}$. We study the transformation under $S$-duality of the Calabi-Yau Yukawa couplings.

hep-th↗
arXiv1995

A Note on the String Analog of $N=2$ Super-Symmetric Yang-Mills

A connection between the conifold locus of the type II string on the $W\:P_{11226}^4$ Calabi-Yau manifold and the geometry of the quantum moduli of $N = 2$ $SU(2)$ super Yang-Mills is presented. This relation is obtained from the anomalous behaviour of the $SU(2)$ super Yang-Mills special coordinates under $S$-duality transformation in $Sl(2;Z) / Γ_2$.

hep-th↗
arXiv1995

From Quantum Monodromy to Duality

For $N\!=\!2$ SUSY theories with non-vanishing $β$-function and one-dimensional quantum moduli, we study the representation on the special coordinates of the group of motions on the quantum moduli defined by $Γ_W\!=\!Sl(2;Z)\!/\!Γ_M$, with $Γ_M$ the quantum monodromy group. $Γ_W$ contains both the global symmetries and the strong-weak coupling duality. The action of $Γ_W$ on the special coordinates is not part of the symplectic group $Sl(2;Z)$. After coupling to gravity, namely in the context of non-rigid special geometry, we can define the action of $Γ_W$ as part of $Sp(4;Z)$. To do this requires singular gauge transformations on the "scalar" component of the graviphoton field. In terms of these singular gauge transformations the topological obstruction to strong-weak duality can be interpreted as a $σ$-model anomaly, indicating the possible dynamical role of the dilaton field in $S$-duality.

hep-th↗
arXiv1995

On the String Interpretation of the $t{\bar t}$-geometry

We derive the $t{\bar t}$-equations for generic $N\!=\!2$ topological field theories as consistency conditions for the contact term algebra of topological strings. A generalization of the holomorphic anomaly equation, known for the critical ${\hat c}\!=\!3$ case, to arbitrary non critical topological strings is presented. The interplay between the non trivial cohomology of the $b$-antighost, gravitational descendants and $\bar t$-dependence is discussed. The physical picture emerging from this study is that the $\bar t$ (background) dependence of topological strings with non trivial cohomology for the $b$-antighost, is determined by gravitational descendants.

hep-th↗
arXiv1994

Topology and Strings: Topics in $N=2$

A review on topological strings and the geometry of the space of two dimensional theories. (Lectures given by C. Gomez at the Enrico Fermi Summer School, Varenna, July 1994)

hep-th↗
arXiv1994

On the Algebraic Structure of the Holomorphic Anomaly for N=2 Topological Strings

The special geometry ($(t,{\bar t})$-equations) for twisted $N=2$ strings are derived as consistency conditions of a new contact term algebra. The dilaton appears in the contact terms of topological and antitopological operators. The holomorphic anomaly, which can be interpreted as measuring the background dependence, is obtained from the contact algebra relations.

hep-th↗
arXiv1993

Quantum Clifford-Hopf Algebras for Even Dimensions

In this paper we study the quantum Clifford-Hopf algebras $\widehat{CH_q(D)}$ for even dimensions $D$ and obtain their intertwiner $R-$matrices, which are elliptic solutions to the Yang- Baxter equation. In the trigonometric limit of these new algebras we find the possibility to connect with extended supersymmetry. We also analyze the corresponding spin chain hamiltonian, which leads to Suzuki's generalized $XY$ model.

hep-th↗