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E. Sezgin

Publications and source records attributed to E. Sezgin.

At least 91 records · Page 5Linked to original sources
arXiv1994

Search for Duality Symmetries in p-Brane Theories

The requirement of an $SL(2)$ duality symmetry, mixing the worldvolume field equations with Bianchi identities, leads to a highly nonlinear equation involving the transformation parameters and certain worldvolume currents. In general, this equation seems to admit a solution only for a two parameter subgroup of the seeked $SL(2)$. These transformations also leave invariant the first class constraints generating the worldvolume reparametrizations. In the special case of $p$--branes in $p+1$ dimensions, the full $SL(2)$ is realized.

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arXiv1994

A Superstring Theory in 2+2 Dimensions

In this paper we construct a $(2,2)$ dimensional string theory with manifest $N=1$ spacetime supersymmetry. We use Berkovits' approach of augmenting the spacetime supercoordinates by the conjugate momenta for the fermionic variables. The worldsheet symmetry algebra is a twisted and truncated ``small'' $N=4$ superconformal algebra. The physical spectrum of the open string contains an infinite number of massless states, including a supermultiplet of a self-dual Yang-Mills field and a right-handed spinor and a supermultiplet of an anti-self-dual Yang-Mills field and a left-handed spinor. The higher-spin multiplets are natural generalisations of these self-dual and anti-self-dual multiplets.

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arXiv1994

On Target-Space Duality in p-Branes

We study the target-space duality transformations in $p$--branes as transformations which mix the worldvolume field equations with Bianchi identities. We consider an $(m+p+1)$-dimensional spacetime with $p+1$ dimensions compactified, and a particular form of the background fields. We find that while a $GL(2)=SL(2)\times R$ group is realized when $m=0$, only a two parameter group is realized when $m>0$.

hep-th↗
arXiv1993

Twistor-like Formulation of Super p-Branes

Closed super (p+2)-forms in target superspace are relevant for the construction of the usual super p-brane actions. Here we construct closed super (p+1)-forms on a {\it worldvolume superspace}. They are built out of the pull-backs of the Kalb-Ramond super (p+1)-form and its curvature. We propose a twistor-like formulation of a class of super p-branes which crucially depends on the existence of these closed super (p+1)-forms.

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arXiv1993

Aspects of $κ$--symmetry

We review various aspects of a fermionic gauge symmetry, known as the $κ$--symmetry, which plays an important role in formulations of superstrings, supermembranes and higher dimensional extended objects. We also review some aspects of the connection between $κ$--symmetric theories and their twistor-like formulations.

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arXiv1993

BRST Operator for Superconformal Algebras with Quadratic Nonlinearity

We construct the quantum BRST operators for a large class of superconformal and quasi--superconformal algebras with quadratic nonlinearity. The only free parameter in these algebras is the level of the (super) Kac-Moody sector. The nilpotency of the quantum BRST operator imposes a condition on the level. We find this condition for (quasi) superconformal algebras with a Kac-Moody sector based on a simple Lie algebra and for the $Z_2\times Z_2$--graded superconformal algebras with a Kac-Mody sector based on the superalgebra $osp(N\vert 2M)$ or $s\ell(N+2\vert N)$.

hep-th↗
arXiv1992

Self duality and supersymmetry

Chiral/self-dual restrictions of various super Yang-Mills and supergravity theories in (2,2) dimensions are described. These include the N=1 supergravity with a cosmological term and the N=1 new minimal supergravity theory. In the latter case, a self-duality condition on a torsionful Riemann curvature is possible, and it implies the equations of motion that follow from an $R^2$ type supergravity action.

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arXiv1992

$U(1)$--Extended Gauge Algebras in $p$-Loop Space

We consider, for $p$ odd, a $p$--brane coupled to a $(p+1)$th rank background antisymmetric tensor field and to background Yang-Mills (YM) fields {\it via} a Wess-Zumino term. We obtain the generators of antisymmetric tensor and Yang-Mills gauge transformations acting on $p$--brane wavefunctionals (functions on `$p$-loop space'). The Yang-Mills generators do not form a closed algebra by themselves; instead, the algebra of Yang-Mills and antisymmetric tensor generators is a $U(1)$ extension of the usual algebra of Yang-Mills gauge transformations. We construct the $p$-brane's Hamiltonian and thereby find gauge-covariant functional derivatives acting on $p$--brane wavefunctionals that commute with the YM and $U(1)$ generators.

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arXiv1992

Symmetries of P-Branes

Using canonical methods, we study the invariance properties of a bosonic $p$--brane propagating in a curved background locally diffeomorphic to $M\times G$, where $M$ is spacetime and $G$ a group manifold. The action is that of a gauged sigma model in $p+1$ dimensions coupled to a Yang--Mills field and a $(p+1)$--form in $M$. We construct the generators of Yang-Mills and tensor gauge transformations and exhibit the role of the $(p+1)$--form in cancelling the potential Schwinger terms. We also discuss the Noether currents associated with the global symmetries of the action and the question of the existence of infinite dimensional symmetry algebras, analogous to the Kac-Moody symmetry of the string.

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arXiv1992

Discrete States in the $W_3$ String

We construct the low-lying discrete states of the two-scalar $W_3$ string. This includes states that correspond to the analogues of the ground ring generators of the ordinary two-dimensional string. These give rise to infinite towers of discrete states at higher levels.

hep-th↗
arXiv1992

Nonlinear Realisations of $w_{1+\infty}$

The nonlinear scalar-field realisation of $w_{1+\infty}$ symmetry in $d=2$ dimensions is studied in analogy to the nonlinear realisation of $d=4$ conformal symmetry $SO(4,2)$. The $w_{1+\infty}$ realisation is derived from a coset-space construction in which the divisor group is generated by the non-negative modes of the Virasoro algebra, with subsequent application of an infinite set of covariant constraints. The initial doubly-infinite set of Goldstone fields arising in this construction is reduced by the covariant constraints to a singly-infinite set corresponding to the Cartan-subalgebra generators $v^\ell_{-(\ell+1)}$. We derive the transformation rules of this surviving set of fields, finding a triangular structure in which fields transform into themselves or into lower members of the set only. This triangular structure gives rise to finite-component subrealisations, including the standard one for a single scalar. We derive the Maurer-Cartan form and discuss the construction of invariant actions.

hep-th↗
arXiv1992

Self-Dual Supergravity Theories in 2+2 Dimensions

Starting from the new minimal multiplet of supergravity in $2+2$ dimensions, we construct two types of self-dual supergravity theories. One of them involves a self-duality condition on the Riemann curvature and implies the equations of motion following from the Hilbert-Einstein type supergravity action. The other one involves a self-duality condition on a {\it torsionful} Riemann curvature with the torsion given by the field-strength of an antisymmetric tensor field, and implies the equations of motion that follow from an $R^2$-type action.

hep-th↗
arXiv1992

Self-Duality in 3+3 Dimensions and the KP Equation

We consider two types of generalized self-duality conditions for Yang-Mills fields on paracomplex manifolds of arbitrary dimension. We then specialize to $3+3$ dimensions and show how one can obtain the KP equation from these self-duality conditions on $SL(2,R)$ valued gauge fields.

hep-th↗
arXiv1992

Area-Preserving Diffeomorphisms, w_\infty Algebras and w_\infty Gravity

The w_\infty algebra is a particular generalization of the Virasoro algebra with generators of higher spin 2,3,...,\infty. It can be viewed as the algebra of a class of functions, relative to a Poisson bracket, on a suitably chosen surface. Thus, w_\infty is a special case of area-preserving diffeomorphisms of an arbitrary surface. We review various aspects of area- preserving diffeomorphisms, w_\infty algebras and w_\infty gravity. The topics covered include a) the structure of the algebra of area-preserving diffeomorphisms with central extensions and their relation to w_\infty algebras, b) various generalizations of w_\infty algebras, c) the structure of w_\infty gravity and its geometrical aspects, d) nonlinear realizations of w_\infty symmetry and e) various quantum realizations of w_\infty symmetry.

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arXiv1992

The Coupling of Yang-Mills to Extended Objects

The coupling of Yang-Mills fields to the heterotic string in bosonic formulation is generalized to extended objects of higher dimension (p-branes). For odd p, the Bianchi identities obeyed by the field strengths of the (p+1)-forms receive Chern-Simons corrections which, in the case of the 5-brane, are consistent with an earlier conjecture based on string/5-brane duality.

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arXiv1991

Aspects of W_\INFTY Symmetry

We review the structure of W_\infty algebras, their super and topological extensions, and their contractions down to (super) w_\infty. Emphasis is put on the field theoretic realisations of these algebras. We also review the structure of w_\infty and W_\infty gravities and comment on various applications of W_\infty symmetry.

hep-th↗
arXiv1991

Quantum Mechanics on the Circle and W_{1+\INFTY}

The algebra W_{1+\infty} with central charge c=0 can be identified with the algebra of quantum observables of a particle moving on a circle. Mathematically, it is the universal enveloping algebra of the Euclidean algebra in two dimensions. Similarly, the super W_\infty algebra is found to be the universal enveloping algebra of the super-Euclidean algebra in two dimensions.

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