Results 1  10
of
38
Discrete torsion orbifolds and Dbranes
 II, J. High Energy Phys
"... Dbranes on orbifolds with and without discrete torsion are analysed in a unified way using the boundary state formalism. For the example of the Z2 × Z2 orbifold it is found that both the theory with and without discrete torsion possess Dbranes whose worldvolume carries conventional and projective ..."
Abstract

Cited by 25 (4 self)
 Add to MetaCart
(Show Context)
Dbranes on orbifolds with and without discrete torsion are analysed in a unified way using the boundary state formalism. For the example of the Z2 × Z2 orbifold it is found that both the theory with and without discrete torsion possess Dbranes whose worldvolume carries conventional and projective representations of the orbifold group. The resulting Dbrane spectrum is shown to be consistent with Tduality.
Marginal and relevant deformations of N=4 field theories and noncommutative moduli spaces of vacua”, JHEP 0005
, 2000
"... Abstract: We study marginal and relevant supersymmetric deformations of the N = 4 superYangMills theory in four dimensions. Our primary innovation is the interpretation of the moduli spaces of vacua of these theories as noncommutative spaces. The construction of these spaces relies on the represe ..."
Abstract

Cited by 24 (3 self)
 Add to MetaCart
(Show Context)
Abstract: We study marginal and relevant supersymmetric deformations of the N = 4 superYangMills theory in four dimensions. Our primary innovation is the interpretation of the moduli spaces of vacua of these theories as noncommutative spaces. The construction of these spaces relies on the representation theory of the related quantum algebras, which are obtained from Fterm constraints. These field theories are dual to superstring theories propagating on deformations of the AdS5×S 5 geometry. We study Dbranes propagating in these vacua and introduce the appropriate notion of algebraic geometry for noncommutative spaces. The resulting moduli spaces of Dbranes have several novel features. In particular, they may be interpreted as symmetric products of noncommutative spaces. We show how mirror symmetry between these deformed geometries and orbifold theories follows from Tduality. Many features of the dual closed string theory may be identified within the noncommutative algebra. In particular, we make progress towards understanding the Ktheory necessary for backgrounds where the NeveuSchwarz antisymmetric tensor of the string is turned on, and we shed light on some aspects of discrete
A Note on the Equivalence of Vafa’s and Douglas’s Picture of Discrete Torsion,” hepth/0009045
"... For a general nonabelian group action and an arbitrary genus worldsheet we show that Vafa’s old definition of discrete torsion coincides with Douglas’s Dbrane definition of discrete torsion associated to projective representations. 1 Vafa’s picture Discrete torsion was introduced many years ago by ..."
Abstract

Cited by 14 (0 self)
 Add to MetaCart
(Show Context)
For a general nonabelian group action and an arbitrary genus worldsheet we show that Vafa’s old definition of discrete torsion coincides with Douglas’s Dbrane definition of discrete torsion associated to projective representations. 1 Vafa’s picture Discrete torsion was introduced many years ago by Vafa in [1]. More recently Douglas [2] introduced an alternative picture in terms of Dbranes. The purpose of this note is to show the equivalence of these pictures. Since both of these papers were very brief as regards to the general case we will review both constructions here. In general a worldsheet Σ of genus g and no boundary will be associated to a given phase dictated by the Bfield and the homology class of the worldsheet in the target space. Vafa wanted to generalize this notion of a Bfield to the case of orbifolds with fixed points. In order to localize the picture let us consider a discrete group Γ acting on C n where the origin is fixed by all of Γ. The worldsheet Σ on this orbifold may be pictured as a disk in the covering C n where the edges of the disk are identified by elements of the action of Γ. That is, the usual homology 1cycles of the worldsheet Σ are twisted by elements of Γ.
Discrete torsion, nonAbelian orbifolds and the Schur multiplier,” hepth/0010023
"... Preprint typeset in JHEP style. HYPER VERSION ..."
(Show Context)
Open strings in simple current orbifolds
"... We study branes and open strings in a large class of orbifold backgrounds using microscopic techniques of boundary conformal field theory. In particular, we obtain factorizing operator product expansions of open string vertex operators for such branes. Applications include branes in Z2 orbifolds of ..."
Abstract

Cited by 11 (2 self)
 Add to MetaCart
(Show Context)
We study branes and open strings in a large class of orbifold backgrounds using microscopic techniques of boundary conformal field theory. In particular, we obtain factorizing operator product expansions of open string vertex operators for such branes. Applications include branes in Z2 orbifolds of the SU(2) WZW model and in the Dseries of unitary minimal models considered previously by Runkel.
On Algebraic Singularities, Finite Graphs and DBrane Gauge Theories: A String Theoretic Perspective
, 2002
"... In this writing we shall address certain beautiful interrelations between the construction of 4dimensional supersymmetric gauge theories and resolution of algebraic singularities, from the perspective of String Theory. We review in some detail the requisite background in both the mathematics, such ..."
Abstract

Cited by 11 (8 self)
 Add to MetaCart
In this writing we shall address certain beautiful interrelations between the construction of 4dimensional supersymmetric gauge theories and resolution of algebraic singularities, from the perspective of String Theory. We review in some detail the requisite background in both the mathematics, such as orbifolds, symplectic quotients and quiver representations, as well as the physics, such as gauged linear sigma models, geometrical engineering, HananyWitten setups and Dbrane probes. We investigate aspects of worldvolume gauge dynamics using Dbrane resolutions of various CalabiYau singularities, notably Gorenstein quotients and toric singularities. Attention will be paid to the general methodology of constructing gauge theories for these singular backgrounds, with and without the presence of the NSNS Bfield, as well as the Tduals to brane setups and branes wrapping cycles in the mirror geometry. Applications of such diverse and elegant mathematics as crepant resolution of algebraic singularities, representation of finite groups and finite graphs, modular invariants of affine Lie algebras, etc. will naturally arise. Various viewpoints and generalisations of McKay’s Correspondence will also be considered. The present work is a transcription of excerpts from the first three volumes of the author’s PhD thesis which was written under the direction of Prof. A. Hanany to whom he is much indebted at the Centre for Theoretical Physics of MIT, and which, at the suggestion of friends, he posts to the ArXiv pro hac vice; it is his sincerest wish that the ensuing pages might be of some small use to the beginning student.
Discrete Torsion, Covering Groups and Quiver Diagrams
, 2001
"... Preprint typeset in JHEP style. HYPER VERSION ..."
Dbranes, discrete torsion and the McKay correspondence,” hepth/0009042
"... We analyze the Dbranes of a type IIB string theory on an orbifold singularity including the possibility of discrete torsion following the work of Douglas et al. First we prove some general results about the moduli space of a point associated to the “regular representation ” of the orbifold group. T ..."
Abstract

Cited by 8 (0 self)
 Add to MetaCart
We analyze the Dbranes of a type IIB string theory on an orbifold singularity including the possibility of discrete torsion following the work of Douglas et al. First we prove some general results about the moduli space of a point associated to the “regular representation ” of the orbifold group. This includes some analysis of the “wrapped branes ” which necessarily appear when the orbifold singularity is not isolated. Next we analyze the stringy homology of the orbifold using the McKay correspondence and the relationship between Ktheory and homology. We find that discrete torsion and torsion in this stringy homology are closelyrelated concepts but that they differ in general. Lastly we question to what extent the D1 brane may be thought of as being Dbranes as probes of string theory in nontrivial backgrounds have been a source of useful insights since [1]. In [2] Douglas and Moore used a quotient construction to study the dynamics of branes at an orbifold singularity. The construction involves a choice of a representation of the quotient group on the Chan–Paton indices. This leads to a supersymmetric