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D. Kutasov

Publications and source records attributed to D. Kutasov.

35 records · Page 2Linked to original sources
arXiv1998

String Theory in Magnetic Monopole Backgrounds

We discuss string propagation in the near-horizon geometry generated by Neveu-Schwarz fivebranes, Kaluza-Klein monopoles and fundamental strings. When the fivebranes and KK monopoles are wrapped around a compact four-manifold $\MM$, the geometry is $AdS_3\times S^3/\ZZ_N\times \MM$ and the spacetime dynamics is expected to correspond to a local two dimensional conformal field theory. We determine the moduli space of spacetime CFT's, study the spectrum of the theory and compare the chiral primary operators obtained in string theory to supergravity expectations.

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arXiv1998

Brane Dynamics and Gauge Theory

We review some aspects of the interplay between the dynamics of branes in string theory and the classical and quantum physics of gauge theories with different numbers of supersymmetries in various dimensions.

hep-th↗
arXiv1998

Comments on String Theory on $AdS_3$

We study string propagation on $AdS_3$ times a compact space from an ``old fashioned'' worldsheet point of view of perturbative string theory. We derive the spacetime CFT and its Virasoro and current algebras, thus establishing the conjectured $AdS$/CFT correspondence for this case in the full string theory. Our results have implications for the extreme IR limit of the $D1-D5$ system, as well as to 2+1 dimensional BTZ black holes and their Bekenstein-Hawking entropy.

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arXiv1998

Algebraic Aspects of Matrix Theory on T^d

We study the exceptional U duality group $E_d$ of M-theory compactified on a d-torus and its representations using Matrix theory. We exhibit the $E_d$ structure and show that p-branes wrapped or unwrapped around the longitudinal direction form representations of the U duality group together with other, more mysterious, states.

hep-th↗
arXiv1997

Brane Dynamics and N=1 Supersymmetric Gauge Theory

We discuss some aspects of the relation between space-time properties of branes in string theory, and the gauge theory on their worldvolume, for models invariant under four supercharges in three and four dimensions. We show that a simple set of rules governing brane dynamics reproduces many features of gauge theory. We study theories with $U(N_c)$, $SO(N_c)$ and $Sp(N_c)$ gauge groups and matter in the fundamental and two index tensor representations, and use the brane description to establish Seiberg's electric-magnetic duality for these models.

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arXiv1997

M-branes and N=2 Strings

The string field theory of N=(2,1) heterotic strings describes a set of self-dual Yang-Mills fields coupled to self-dual gravity in 2+2 dimensions. We show that the exact classical action for this field theory is a certain complexification of the Green-Schwarz/Dirac-Born-Infeld string action, closely related to the four dimensional Wess-Zumino action describing self-dual gauge fields. This action describes the world-volume of a 2+2d ``M-brane'', which gives rise upon different null reductions to critical strings and membranes. We discuss a number of further properties of N=2 heterotic strings, such as the geometry of null reduction, general features of a covariant formulation, and possible relations to BPS and GKM algebras.

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arXiv1996

New Principles for String/Membrane Unification

The target space theory of the N=(2,1) heterotic string may be interpreted as a theory of gravity coupled to matter in either $1+1$ or $2+1$ dimensions. Among the target space theories in $1+1$ dimensions are the bosonic, type II, and heterotic string world sheet field theories in a physical gauge. The $2+1$ dimensional version describes a consistent quantum theory of supermembranes in $10+1$ dimensions. The unifying framework for all of these vacua is a theory of $2+2$ dimensional self-dual geometries embedded in $10+2$ dimensions. There are also indications that the N=(2,1) string describes the strong coupling dynamics of compactifications of critical string theories to two dimensions, and may lead to insights about the fundamental degrees of freedom of the theory.

hep-th↗
arXiv1995

Chiral Rings, Singularity Theory and Electric-Magnetic Duality

We study in detail the space of perturbations of a pair of dual $N=1$ supersymmetric theories based on an $SU(N_c)$ gauge theory with an adjoint $X$ and fundamentals with a superpotential which is polynomial in $X$. The equivalence between them depends on non-trivial facts about polynomial equations, i.e.\ singularity theory. The classical chiral rings of the two theories are different. Quantum mechanically there are new relations in the chiral rings which ensure their equivalence. Duality interchanges ``trivial'' classical relations in one theory with quantum relations in the other and vice versa. We also speculate about the behavior of the theory without the superpotential.

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arXiv1995

On Duality in Supersymmetric Yang-Mills Theory

We discuss non-abelian $SU(N_c)$ gauge theory coupled to an adjoint chiral superfield $X$, and a number of fundamental chiral superfields $Q^i$. Using duality, we show that turning on a superpotential $W(X)=\Tr\sum_{l=1}^k g_l X^{l+1}$ leads to non-trivial long distance dynamics, a large number of multicritical IR fixed points and vacua, connected to each other by varying the coefficients $g_l$.

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arXiv1995

A Comment on Duality in N=1 Supersymmetric Non -- Abelian Gauge Theories

Recently N. Seiberg has shown that certain N=1 supersymmetric Yang -- Mills theories have the property that their infrared physics can be equivalently described by {\it two different} gauge theories, with the strong coupling region of one corresponding to the weak coupling region of the other. This duality leads to interesting results about the infrared dynamics of these theories. We generalize Seiberg's ideas to a new class of models for which a similar duality allows one to obtain rather detailed dynamical information about the long distance physics.

hep-th↗
arXiv1995

Universality in Two Dimensional Gauge Theory.

We discuss two dimensional Yang -- Mills theories with massless fermions in arbitrary representations of a gauge group $G$. It is shown that the physics (spectrum and interactions) of the massive states in such models is independent of the detailed structure of the model, and only depends on the gauge group $G$ and an integer $k$ measuring the total anomaly. The massless physics, which does depend on the details of the model, decouples (almost) completely from that of the massive one. As an example, we discuss the equivalence of QCD$_2$ coupled to fermions in the adjoint, and fundamental representations.

hep-th↗
arXiv1992

Scattering of Open and Closed Strings in 1+1 Dimensions

The ground ring structure of 1+1 dimensional string theory leads to an infinite set of non linear recursion relations among the `bulk' scattering amplitudes of open and closed tachyons on the disk, which fix them uniquely. The relations are generated by the action of the ring on the tachyon modules; associativity of this action determines all structure constants. This algebraic structure may allow one to relate the continuum picture to a matrix model.

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arXiv1991

Ground Rings and Their Modules in 2D Gravity with $c\le 1$ Matter

All solvable two-dimensional quantum gravity models have non-trivial BRST cohomology with vanishing ghost number. These states form a ring and all the other states in the theory fall into modules of this ring. The relations in the ring and in the modules have a physical interpretation. The existence of these rings and modules leads to nontrivial constraints on the correlation functions and goes a long way toward solving these theories in the continuum approach.

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arXiv1991

Some Properties of (Non) Critical Strings

We review some recent developments in string theory, emphasizing the importance of vacuum instabilities, their relation to the density of states, and the role of space-time fermions in non-critical string theory. We also discuss the classical dynamics of two dimensional string theory.

hep-th↗
arXiv1991

Open String Theory in 1+1 Dimensions

We show that tree level open two dimensional string theory is exactly solvable; the solution exhibits some unusual features, and is qualitatively different from the closed case. The open string ``tachyon'' S -- matrix describes free fermions, which can be interpreted as the quarks at the ends of the string. These ``quarks'' live naturally on a lattice in space-time. We also find an exact vacuum solution of the theory, corresponding to a charged black hole.

hep-th↗
arXiv1991

World Sheet and Space Time Physics in Two Dimensional (Super) String Theory

We show that tree level ``resonant'' $N$ tachyon scattering amplitudes, which define a sensible ``bulk'' S -- matrix in critical (super) string theory in any dimension, have a simple structure in two dimensional space time, due to partial decoupling of a certain infinite set of discrete states. We also argue that the general (non resonant) amplitudes are determined by the resonant ones, and calculate them explicitly, finding an interesting analytic structure. Finally, we discuss the space time interpretation of our results.

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