14815654
Exact duality and nilpotent gauging
We obtain new duality transformations, relating some exact string backgrounds, by defining the nilpotent duality. We show that the ungauged SL(2, ℝ) WZW model transforms by its action into the three-dimensional plane wave geometry. We also give the inverse transformation from the plane wave to the SL(2, ℝ) model and discuss the implications of the results.
15254278
D-instantons and Black Holes in N=2, D=4 Supergravity
We discuss T-duality between the solutions of type II A versus type II B superstrings compactiied on Calabi-Yau threefolds. Within the context of N = 2, D = 4 supergravity eeective Lagrangian, the T-duality transformation is equivalently described by the c-map, which transforms the IIA black hole solutions into the IIB D-instanton solutions. We construct via this mapping a broad class of D-instanton solutions in four dimensions.
118306090
Role of Tachyon in the Graceful Exit Problem
119487700
FOUR-DIMENSIONAL TWO-BRANE SOLUTION IN CHIRAL GAUGED WESS-ZUMINO-WITTEN MODEL
An exact conformal field theory describing a four-dimensional two-brane solution is found by considering a chiral gauged Wess-Zumino-Witten theory corresponding to SL(2, R)× R, where one gauges the one-dimensional U(1) subgroup together with a translation in R. The backgrounds for string propagation are explicitly obtained and the target space is shown to have a true curvature singularity.
120115173
A SIX-POINT AMPLITUDE FOR OPEN TEN-DIMENSIONAL SUPERSTRING IN BOSONIC FORMULATION
The two bosons and four fermions scattering amplitude has been calculated using the ideas of bosonization lattice, cocycles, covariant spin fields and superconformal techniques.
122300442
Perturbed superpotentials for coset models
Abstract A class of topological minimal matter corresponding to some of the coset models of Kazama and Suzuki is investigated. Starting from the general principle, the perturbed superpotentials for the corresponding models are explicitly constructed. These perturbed. superpotentials contain all the information about physical amplitudes in the topological theory.
118521608
Black hole entropy corrections in the grand canonical ensemble
We study entropy corrections due to thermal fluctuations for asymptotically AdS black holes in the grand canonical ensemble. To leading order, these can be expressed in terms of the black hole response coefficients via fluctuation moments. We also analyze entropy corrections due to mass and charge fluctuations of R-charged black holes, and our results indicate an universality in the logarithmic corrections to charged AdS black hole entropy in various dimensions.
118116271
Directed Random Walks on Colored, Periodic Lattices: A Gauge Theoretic Approach
We define a random walk problem which admits analytic results, on a class of infinite periodic lattices which are directed and colored. Our approach is motivated from the fact that such lattices arise in string theoretic constructs of certain gauge theories. An operator counting problem in the latter is mapped to a problem in random walks. This is illustrated with several examples.