arXiv subjects

El Hassan Saidi

Publications and source records attributed to El Hassan Saidi.

50 records · Page 3Linked to original sources

arXiv2006

Topological SL(2) Gauge Theory on Conifold

Using a two component $SL(2) $ isospinor formalism, we study the link between conifold $T^{\ast}\mathbb{S}^{3}$ and q-deformed non commutative holomorphic geometry in complex four dimensions. Then, thinking about conifold as a projective complex three dimension hypersurface embedded in non compact $WP^{5}(1,-1,1,-1,1,-1) $ space and using conifold local isometries, we study topological $SL(2) $ gauge theory on $T^{\ast}\mathbb{S}^{3}$ and its reductions to lower dimension sub-manifolds $T^{\ast}\mathbb{S}^{2}$, $T^{\ast}\mathbb{S}^{1}$ and their real slices. Projective symmetry is also used to build a supersymmetric QFT$%_{4}$ realization of these backgrounds. Extensions for higher dimensions with conifold like properties are explored. \bigskip \textbf{Key words}: Conifold, q-deformation, non commutative complex geometry, topological gauge theory. Nambu like background.

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arXiv2005

Calogero model with Yukawa like interaction

We study an extension of one dimensional Calogero model involving strongly coupled and electrically charged particles. Besides Calogero term $\frac{g}{% 2x^{2}}$, there is an extra factor described by a Yukawa like coupling modeling short distance interactions. Mimicking Calogero analysis and using developments in formal series of the wave function $Ψ(x) $ factorised as $x^εΦ(x) $ with $ε(ε-1) =g$, we develop a technique to approach the spectrum of the generalized system and show that information on full spectrum is captured by $Φ(x) $ and $Φ^{\prime \prime}(x) $ at the singular point $x=0$ of the potential. Convergence of $% \int dx| Ψ(x) | ^{2}$ requires $ε>-{1/2}$ and is shown to be sensitive to the zero mode of $Φ(x) $ at $x=0$. \textbf{Key words}: \textit{Hamitonian systems, quantum integrability, Calogero model, Yukawa like potential.}

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arXiv2005

Non-commutative ADE geometries as holomorphic wave equations

Borrowing ideas from the relation between classical and quantum mechanics, we study a non-commutative elevation of the ADE geometries involved in building Calabi-Yau manifolds. We derive the corresponding geometric hamiltonians and the holomorphic wave equations representing these non-commutative geometries. The spectrum of the holomorphic waves is interpreted as the quantum moduli space. Quantum A_1 geometry is analyzed in some details and is found to be linked to the Whittaker differential equation.

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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.

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arXiv2005

Hyperbolic Invariance in Type II Superstrings

We first review aspects of Kac Moody indefinite algebras with particular focus on their hyperbolic subset. Then we present two field theoretical systems where these structures appear as symmetries. The first deals with complete classification of $\mathcal{N}=2$ supersymmetric CFT$_{4}$s and the second concerns the building of hyperbolic quiver gauge theories embedded in type IIB superstring compactification of Calabi-Yau threefolds. We show, amongst others, that $\mathcal{N}=2$ CFT$_{4}$s are classified by Vinberg theorem and hyperbolic structure is carried by the axion modulus. Keywords: Classification of KM algebras, Indefinite KM sector and Hyperbolic subset, Quiver gauge theories embedded in type II superstrings.

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arXiv2004

Hyperbolic Invariance

Motivated by the study of duality cascades in supersymmetric quiver gauge theories beyond affine models, we develop in this paper the analysis of a class of simply laced hyperbolic Lie algebras. These are specific generalizations of affine ADE symmetries which form a particular subclass of the so-called Indefinite Lie algebras. Because of indefinite signature of their bilinear form, we show that these infinite dimensional invariances have very special features and admit a remarkable link type IIB background with non zero axion. We also show that hyperbolic root system $Δ_{hyp}$ has a $\mathbb{Z}_{2}\mathbb{\times Z}_{3}$ gradation containing two specific and isomorphic proper subsets of affine Kac-Moody root systems baptized as $Δ_{affine}^δ$ and $Δ_{affine}^γ$. We give an explicit form of the commutation relations for hyperbolic ADE algebras and analyze their Weyl groups W$_{hyp}$. Comments regarding links with Seiberg like dualities and RG cascades are made.

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arXiv2003

Toric Varieties with NC Toric Actions: NC Type IIA Geometry

Extending the usual $\mathbf{C}^{\ast r}$ actions of toric manifolds by allowing asymmetries between the various $\mathbf{C}^{\ast}$ factors, we build a class of non commutative (NC) toric varieties $\mathcal{V}%_{d+1}^{(nc)}$. We construct NC complex $d$ dimension Calabi-Yau manifolds embedded in $\mathcal{V}_{d+1}^{(nc)}$ by using the algebraic geometry method. Realizations of NC $\mathbf{C}^{\ast r}$ toric group are given in presence and absence of quantum symmetries and for both cases of discrete or continuous spectrums. We also derive the constraint eqs for NC Calabi-Yau backgrounds $\mathcal{M}_{d}^{nc}$ embedded in $\mathcal{V}_{d+1}^{nc}$ and work out their solutions. The latters depend on the Calabi-Yau condition $% \sum_{i}q_{i}^{a}=0$, $q_{i}^{a}$ being the charges of $\mathbf{C}^{\ast r}$% ; but also on the toric data ${q_{i}^{a},ν_{i}^{A};p_{I}^α,ν_{iA}^{\ast}} $ of the polygons associated to $\mathcal{V}%_{d+1}$. Moreover, we study fractional $D$ branes at singularities and show that, due to the complete reducibility property of $\mathbf{C}^{\ast r}$ group representations, there is an infinite number of fractional $D$ branes. We also give the generalized Berenstein and Leigh quiver diagrams for discrete and continuous $\mathbf{C}^{\ast r}$ representation spectrums. An illustrating example is presented.

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arXiv2003

NC Geometry and Fractional Branes

Considering complex $n$-dimension Calabi-Yau homogeneous hyper-surfaces $% \mathcal{H}_{n}$ with discrete torsion and using Berenstein and Leigh algebraic geometry method, we study Fractional D-branes that result from stringy resolution of singularities. We first develop the method introduced in hep-th/0105229 and then build the non commutative (NC) geometries for orbifolds $\mathcal{O}=\mathcal{H}_{n}/\mathbf{Z}_{n+2}^{n}$ with a discrete torsion matrix $t_{ab}=exp[{\frac{i2π}{n+2}}{(η_{ab}-η_{ba})}]$, $η_{ab} \in SL(n,\mathbf{Z})$. We show that the NC manifolds $% \mathcal{O}^{(nc)}$ are given by the algebra of functions on the real $% (2n+4) $ Fuzzy torus $\mathcal{T}_{β_{ij}}^{2(n+2)}$ with deformation parameters $β_{ij}=exp{\frac{i2π}{n+2}}{[(η_{ab}^{-1}-η_{ba}^{-1})} q_{i}^{a} q_{j}^{b}]$ with $q_{i}^{a}$'s being charges of $% \mathbf{Z}_{n+2}^{n}$. We also give graphic rules to represent $\mathcal{O}% ^{(nc)}$ by quiver diagrams which become completely reducible at orbifold singularities. It is also shown that regular points in these NC geometries are represented by polygons with $(n+2)$ vertices linked by $(n+2)$ edges while singular ones are given by $(n+2)$ non connected loops. We study the various singular spaces of quintic orbifolds and analyze the varieties of fractional $D$ branes at singularities as well as the spectrum of massless fields. Explicit solutions for the NC quintic $\mathcal{Q}^{(nc)}$ are derived with details and general results for complex $n$ dimension orbifolds with discrete torsion are presented.

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arXiv2003

Explicit Analysis of Kahler Deformations in 4D N=1 Supersymmetric Quiver Theories

Starting from the $\mathcal{N}=2$ SYM$_{4}$ quiver theory living on wrapped $% N_{i}D5$ branes around $S_{i}^{2}$ spheres of deformed ADE fibered Calabi-Yau threefolds (CY3) and considering deformations using \textit{% massive} vector multiplets, we explicitly build a new class of $\mathcal{N}% =1 $ quiver gauge theories. In these models, the quiver gauge group $% \prod_{i}U(N_{i}) $ is spontaneously broken down to $% \prod_{i}SU(N_{i}) $ and Kahler deformations are shown to be given by the real part of the integral $(2,1) $ form of CY3. We also give the superfield correspondence between the $\mathcal{N}=1$ quiver gauge models derived here and those constructed in hep-th/0108120 using complex deformations. Others aspects of these two dual $\mathcal{N}=1$ supersymmetric field theories are discussed.

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arXiv2003

A Matrix Model for ν_{k_1k_2}=\frac{k_1+k_2}{k_1 k_2} Fractional Quantum Hall States

We propose a matrix model to describe a class of fractional quantum Hall (FQH) states for a system of (N_1+N_2) electrons with filling factor more general than in the Laughlin case. Our model, which is developed for FQH states with filling factor of the form ν_{k_1k_2}=\frac{k_1+k_2}{k_1k_2} (k_1 and k_2 odd integers), has a U(N_1)\times U(N_2) gauge invariance, assumes that FQH fluids are composed of coupled branches of the Laughlin type, and uses ideas borrowed from hierarchy scenarios. Interactions are carried, amongst others, by fields in the bi-fundamentals of the gauge group. They simultaneously play the role of a regulator, exactly as does the Polychronakos field. We build the vacuum configurations for FQH states with filling factors given by the series ν_{p_1p_2}=\frac{p_2}{p_1p_2-1}, p_1 and p_2 integers. Electrons are interpreted as a condensate of fractional D0-branes and the usual degeneracy of the fundamental state is shown to be lifted by the non-commutative geometry behaviour of the plane. The formalism is illustrated for the state at ν={2/5}.

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arXiv2002

NC Calabi-Yau Manifolds in Toric Varieties with NC Torus fibration

Using the algebraic geometry method of Berenstein and Leigh (BL), hep-th/0009209 and hep-th/0105229), and considering singular toric varieties ${\cal V}_{d+1}$ with NC irrational torus fibration, we construct NC extensions ${\cal M}_{d}^{(nc)}$ of complex d dimension Calabi-Yau (CY) manifolds embedded in ${\cal V}_{d+1}^{(nc)}$. We give realizations of the NC $\mathbf{C}^{\ast r}$ toric group, derive the constraint eqs for NC Calabi-Yau (NCCY) manifolds ${\cal M}^{nc}_d$ embedded in ${\cal V}_{d+1}^{nc}$ and work out solutions for their generators. We study fractional $D$ branes at singularities and show that, due to the complete reducibility property of $\mathbf{C}^{\ast r}$ group representations, there is an infinite number of non compact fractional branes at fixed points of the NC toric group.

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arXiv2002

NC Effective Gauge Model for Multilayer FQH States

We develop an effective field model for describing FQH states with rational filling factors that are not of Laughlin type. These kinds of systems, which concern single layer hierarchical states and multilayer ones, were observed experimentally; but have not yet a satisfactory non commutative effective field description like in the case of Susskind model. Using $D$ brane analysis and fiber bundle techniques, we first classify such states in terms of representations characterized, amongst others, by the filling factor of the layers; but also by proper subgroups of the underlying $U(n) $ gauge symmetry. Multilayer states in the lowest Landau level are interpreted in terms of systems of $D2$ branes; but hierarchical ones are realized as Fiber bundles on $D2$ which we construct explicitly. In this picture, Jain and Haldane series are recovered as special cases and have a remarkable interpretation in terms of Fiber bundles with specific intersection matrices. We also derive the general NC commutative effective field and matrix models for FQH states, extending Susskind theory, and give the general expression of the rational filling factors as well as their non abelian gauge symmetries.

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arXiv2001

D-branes on Noncommutative Orbifolds

We study tachyon condensation on noncommutative toric orbifolds with a $Z_2$ discrete group and explore the various kins of brane bound states arising in the case of irrational values of the B-field. We show that $Z_$ symmetry of the orbifolds incorporates naturally anti-branes in the spectrum and leads to equivalent results as those obtained by starting from an original pair of D-barD system on quantum torii. A specific analysis is deserved to the irrational representation of NC orbifolds and to the unstable bound states generated by the condensation.

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arXiv2001

Solitons on compact and noncompact spaces in large noncommutativity

We study solutions at the minima of scalar field potentials for Moyal spaces and torii in the large non-commutativity and interprete these solitons in terms of non-BPS D-branes of string theory. We derive a mass spectrum formula linking different D-branes together on quantum torii and suggest that it describes general systems of D-brane bound states extending the D2-D0 one. Then we propose a shape for the effective potential approaching these quasi-stable bound states. We give the gauge symmetries of these systems of branes and show that they depend on the quantum torii representations.

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