17322810
Planetoid strings: Solutions and perturbations
A novel ansatz for solving the string equations of motion and constraints in generic curved backgrounds, namely the planetoid ansatz, was proposed recently by some authors. We construct several specific examples of planetoid strings in curved backgrounds which include Lorentzian wormholes, spherical Rindler spacetime and the (2 + 1)-dimensional black hole. A semiclassical quantization is performed and the Regge relations for the planetoids are obtained. The general equations for the study of small perturbations about these solutions are written down using the standard, covariant formalism. Applications to special cases such as those of planetoid strings in Minkowski and spherical Rindler spacetimes are also presented.
15171152
NONCOMMUTATIVITY IN LINEAR DILATON BACKGROUND
We consider quantization of open string theories in linear dilaton and constant antisymmetric tensor backgrounds and discuss the noncommutativity of space–time coordinates arising in such theories, including their relationship with light-like noncommutativity as well as backgrounds with null isometries. It is argued that the results can also be understood using space–time equations of motion of the string modes. We then present N = 2 supersymmetric generalization of these theories and the associated noncommutative structure.
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.
121437786
Construction of physical states of non-trivial ghost number in c < 1 string theory
Starting from the Liouville null-vectors in theories of c < 1 matter coupled to 2D gravity, we describe a procedure to explicitly construct elements of the BRS cohomology of ghost number ± 1. A crucial step in the analysis concerns the existence of null-states in the Liouville Fock module, for which a general criterion is obtained. The physical states are shown to satisfy a set of “descent equations”, and we compute their two-point function on the sphere. Our results are illustrated by a number of examples.
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.
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.
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.