arXiv subjects

Dileep P. Jatkar

Publications and source records attributed to Dileep P. Jatkar.

65 records · Page 4Linked to original sources

arXiv1999

Type IIB string theory on AdS_5 X T^{nn'}

We study \kk spectrum of type IIB string theory compactified on $AdS_5 \times T^{nn'}$ in the context of $AdS/CFT$ correspondence. We examine some of the modes of the complexified 2 form potential as an example and show that for the states at the bottom of the \kk tower the corresponding $d=4$ boundary field operators have rational conformal dimensions. The masses of some of the fermionic modes in the bottom of each tower as functions of the $R$ charge in the boundary conformal theory are also rational. Furthermore the modes in the bottom of the towers originating from $q$ forms on $T^{11}$ can be put in correspondence with the BRS cohomology classes of the $c=1$ non critical string theory with ghost number $q$. However, a more detailed investigation is called for, to clarify further the relation of this supergravity background with the $c=1$ strings.

hep-th↗

arXiv1999

Gravitational Couplings and $Z_2$ Orientifolds

The interplay between gravitational couplings on branes and the occurrence of fractional flux in low dimensional orientifolds is examined. It is argued that gravitational couplings need to be assigned not only to D-branes but also to orientifold planes. The fractional charges of the orientifold $d$-planes can be understood in terms of flux quantization of the $d-3$ form potential and modified Bianchi identities. Detailed results are presented for the case of the type IIB orientifold on $T^6/Z_2$, which is dual to F-theory on a complex 4-fold with terminal singularities.

hep-th↗

arXiv1997

Non-perturbative Enhanced Gauge Symmetries in the Gimon-Polchinski Orientifold

We study the enhanced gauge symmetries at constant couplings in the moduli space of the Gimon-Polchinski Orientifold. We show that whenever there is a singularity of E_6, E_7 and E_8 type we get enhanced gauge symmetry U(5), U(6) and U(8) respectively. This is due to the additional twisting involved in the definition of the Gimon-Polchiniski orientifold.

hep-th↗

arXiv1996

Dyonic Black Hole in Heterotic String Theory

We study some features of dyonic Black hole solution in heterotic string theory on a six torus. This solution has 58 parameters. Of these, 28 parameters denote the electric charge of the black hole, another 28 correspond to the magnetic charge, and the other two parameters being the mass and the angular momentum of the black hole. We discuss the extremal limit and show that in various limits, it reduces to the known black hole solutions. The solutions saturating the Bogomolnyi bound are identified. Explicit solution is presented for the non-rotating dyonic black hole.

hep-th↗

arXiv1996

Rotating Dyonic Black Holes in Heterotic String Theory

We study a class of rotating dyonic black holes in the heterotic string theory in four dimension which have left, right independent electric charges but have same magnitude for the left and right magnetic charges. In both left and right sector the electric and the magnetic vectors are orthogonal to each other. The gyromagnetic(electric) ratios are in general found not to have an upper bound.

hep-th↗

arXiv1996

F-theory from Dirichlet 3-branes

Starting from the type IIB Dirichlet 3-brane action, we obtain a Nambu-Goto action. It is interpreted as the world volume action of a fundamental 3-brane, and its target space theory as F-theory. The target space is twelve dimensional, with signature $(11, 1)$. It is an elliptic fibration over a ten dimensional base space. The $SL(2, Z)$ symmetry of type IIB string has now an explicit geometric interpretation. Also, one gets a glimpse of the conjectured self-duality of M-theory.

hep-th↗

arXiv1995

A Calogero-Sutherland Type Model For Branched Polymers

We show that a Calogero-Sutherland type model with anharmonic interactions of fourth and sixth orders leads to the matrix model corresponding to the branched polymers. We also show that by suitably modifying this model one can also obtain N-particle problems which are connected to matrix models corresponding to the pure gravity phase as well as corresponding to the transition point between the soap bubble and the branched polymer phase.

cond-mat↗

arXiv1995

String Theory near a Conifold Singularity

We demonstrate that type II string theory compactified on a singular Calabi-Yau manifold is related to $c=1$ string theory compactified at the self-dual radius. We establish this result in two ways. First we show that complex structure deformations of the conifold correspond, on the mirror manifold, to the problem of maps from two dimensional surfaces to $S^2$. Using two dimensional QCD we show that this problem is identical to $c=1$ string theory. We then give an alternative derivation of this correspondence by mapping the theory of complex structure deformations of the conifold to Chern-Simons theory on $S^3$. These results, in conjunction with similar results obtained for the compactification of the heterotic string on $K_3\times T^2$, provide strong evidence in favour of S-duality between type II strings compactified on a Calabi-Yau manifold and the heterotic string on $K_3\times T^2$.

hep-th↗

arXiv1992

Kleinian Singularities and the Ground Ring of C=1 String Theory

We investigate the nature of the ground ring of c=1 string theory at the special A-D-E points in the c=1 moduli space associated to discrete subgroups of SU(2). The chiral ground rings at these points are shown to define the A-D-E series of singular varieties introduced by Klein. The non-chiral ground rings relevant to closed-string theory are 3 real dimensional singular varieties obtained as U(1) quotients of the Kleinian varieties. The unbroken symmetries of the theory at these points are the volume-preserving diffeomorphisms of these varieties. The theory of Kleinian singularities has a close relation to that of complex hyperKahler surfaces, or gravitational instantons. We speculate on the relevance of these instantons and of self-dual gravity in c=1 string theory.

hep-th↗

arXiv1992

Chirality Ordering of Chiral Spin Liquids

We study the effect of introducing a weak antiferromagnetic interplanar exchange coupling in the two dimensional frustrated Heisenberg model. We show that a ferromagnetic(FM) ordering of chirality - {\it i.e.}, same chirality on adjacent planes - is energetically favoured, thus leading to bulk violation of the discrete symmetries parity($P$) and time reversal($T$).

cond-mat↗

arXiv1992

The Spectrum of Sl(2, R)/U(1) Black Hole Conformal Field Theory

We study string theory in the background of a two-dimensional black hole which is described by an $SL(2, R)/U(1)$ coset conformal field theory. We determine the spectrum of this conformal field theory using supersymmetric quantum mechanics and give an explicit form of the vertex operators in terms of the Jacobi functions. We also discuss the applicability of SUSY quantum mechanics techniques to non-linear $σ$-models.

hep-th↗