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Adil Belhaj

Publications and source records attributed to Adil Belhaj.

63 records · Page 4Linked to original sources
arXiv2005

Superstring Theory on pp Waves with ADE Geometries

We study the BMN correspondence between certain Penrose limits of type IIB superstrings on pp-wave orbifolds with $ADE$ geometries, and the set of four-dimensional $\mathcal{N}=2$ superconformal field theories constructed as quiver gauge models classified by finite $ADE$ Lie algebras and affine $\hat{ADE}$ Kac-Moody algebras. These models have 16 preserved supercharges and are based on systems of D3-branes and wrapped D5- and D7-branes. We derive explicitly the metrics of these pp-wave orbifolds and show that the BMN extension requires, in addition to D5-D5 open strings in bi-fundamental representations, D5-D7 open strings involving orientifolds with $Sp(N)$ gauge symmetry. We also give the correspondence rule between leading string states and gauge-invariant operators in the $\mathcal{N}=2$ quiver gauge models.

hep-th↗
arXiv2005

On toric geometry, Spin(7) manifolds, and type II superstring compactifications

We consider type II superstring compactifications on the singular Spin(7) manifold constructed as a cone on SU(3)/U(1). Based on a toric realization of the projective space CP^2, we discuss how the manifold can be viewed as three intersecting Calabi-Yau conifolds. The geometric transition of the manifold is then addressed in this setting. The construction is readily extended to higher dimensions where we speculate on possible higher-dimensional geometric transitions. Armed with the toric description of the Spin(7) manifold, we discuss a brane/flux duality in both type II superstring theories compactified on this manifold.

hep-th↗
arXiv2004

On Geometric Transitions in String Compactifications

We reconsider the study of the geometric transitions and brane/flux dualities in various dimensions. We first give toric interpretations of the topology changing transitions in the Calabi-Yau conifold and the $Spin(7)$ manifold. The latter, for instance, can be viewed as three intersecting Calabi-Yau conifolds according to $\cp^2$ toric graph. Orbifolds of such geometries are given in terms of del Pezzo complex surfaces. Second we propose a four-dimensional F-theory interpretation of type IIB geometric transitions on the Calabi-Yau conifold. This gives a dual description of the M-theory flop in terms of toric mirror symmetry. In two dimensions, we study the geometric transition in a singular $Spin(7)$ manifold constructed as a cone on SU(3)/U(1). In particular, we discuss brane/flux duality in such a compactification in both type IIA and type IIB superstrings. These examples preserve one supercharge and so have ${\cal N}= 1/2$ supersymmetry in two dimensions. Then, an interpretation in terms of F-theory is given.

hep-th↗
arXiv2004

M-theory on G_2 manifolds and the method of (p,q) brane webs

Using a reformulation of the method of (p,q) webs, we study the four-dimensional N=1 quiver theories from M-theory on seven-dimensional manifolds with G_2 holonomy. We first construct such manifolds as U(1) quotients of eight-dimensional toric hyper-Kähler manifolds, using N=4 supersymmetric sigma models. We show that these geometries, in general, are given by real cones on \bf S^2 bundles over complex two-dimensional toric varieties, \cal \bf V^2= {{\bf C}^{r+2}/ {{\bf C}^*}^r}. Then we discuss the connection between the physics content of M-theory on such G_2 manifolds and the method of (p,q) webs. Motivated by a result of Acharya and Witten [hep-th/0109152], we reformulate the method of $(p,q)$ webs and reconsider the derivation of the gauge theories using toric geometry Mori vectors of \cal \bf V^2 and brane charge constraints. For {\bf WP^2}_{w_1,w_2, w_3}, we find that the gauge group is given by G=U(w_1n)\times U(w_2n)\times U(w_3n). This is required by the anomaly cancellation condition.

hep-th↗
arXiv2003

F-theory Duals of M-theory on G2 Manifolds from Mirror Symmetry

Using mirror pairs (M_3, W_3) in type II superstring compactifications on Calabi-Yau threefolds, we study, geometrically, F-theory duals of M-theory on seven manifolds with G_2 holonomy. We first develop a way for getting Landau Ginzburg (LG) Calabi-Yau threefols W_3, embedded in four complex dimensional toric varieties, mirror to sigma model on toric Calabi-Yau threefolds M_3. This method gives directly the right dimension without introducing non dynamical variables. Then, using toric geometry tools, we discuss the duality between M-theory on (S^1 x M_3)/Z_2 with G_2 holonomy and F-theory on elliptically fibered Calabi-Yau fourfolds with SU(4) holonomy, containing W_3 mirror manifolds. Illustrating examples are presented.

hep-th↗
arXiv2002

Manifolds of G_2 Holonomy from N=4 Sigma Model

Using two dimensional (2D) N=4 sigma model, with $U(1)^r$ gauge symmetry, and introducing the ADE Cartan matrices as gauge matrix charges, we build " toric" hyper-Kahler eight real dimensional manifolds X_8. Dividing by one toric geometry circle action of X_8 manifolds, we present examples describing quotients $X_7={X_8\over U(1)}$ of G_2 holonomy. In particular, for the A_r Cartan matrix, the quotient space is a cone on a $ {S^2}$ bundle over r intersecting $\bf WCP^2_{(1,2,1)}$ projective spaces according to the A_r Dynkin diagram.

hep-th↗
arXiv2001

Mirror Symmetry and Landau Ginzburg Calabi-Yau Superpotentials in F-theory Compactifications

We study Landau Ginzburg (LG) theories mirror to 2D N=2 gauged linear sigma models on toric Calabi-Yau manifolds. We derive and solve new constraint equations for Landau Ginzburg elliptic Calabi-Yau superpotentials, depending on the physical data of dual linear sigma models. In Calabi-Yau threefolds case, we consider two examples. First, we give the mirror symmetry of the canonical line bundle over the Hirzebruch surfaces $\bf F_n$. Second, we find a special geometry with the affine so(8) Lie algebra toric data extending the geometry of elliptically fibered K3. This geometry leads to a pure N=1 six dimensional SO(8) gauge model from the F-theory compactification. For Calabi-Yau fourfolds, we give a new algebraic realization for ADE hypersurfaces.

hep-th↗
arXiv2000

On Geometric Engineering of Supersymmetric Gauge Theories

We present the basic ideas of geometric engineering of the supersymmetric quantum field theories viewed as a low energy limit of type II strings and F-theory on singular Calabi Yau manifolds. We first give the main lines of toric geometry as it is a powerful technique to deal compact complex manifolds. Then we introduce mirror symmetry which plays a crucial role in the study of superstring dualities and finally we give elements on Calabi Yau singularities. After that we study the geometric engineering of N=2 supersymmetric gauge theories in six and four dimensions. Finally we make comments regarding $ N=1$ SYM in four dimensions.

hep-ph↗