We apply the method of Banerjee and Kulkarni (arXiv:0707.2449, [hep-th]) to provide a derivation of Hawking radiation from the GHS (stringy) blackhole which falls in the class of the most general spherically symmetric blackholes ( √−g 6= 1) and also the non-extremal D1−D5 blackhole using only covariant gravitational anomalies.
Pure gravity and gauge theories in two dimensions are shown to be special cases of a much more general class of field theories each of which is characterized by a Poisson structure on a finite dimensional target space. A general scheme for the quantization of these theories is formulated. Explicit examples are studied in some detail. In particular gravity and gauge theories with equivalent actions are compared. Big gauge transformations as well as the condition of metric nondegeneracy in gravity turn out to cause significant differences in the structure of the corresponding reduced phase spaces and the quantum spectra of Dirac observables. For $R^2$ gravity coupled to SU(2) Yang Mills the question of quantum dynamics (`problem of time') is addressed. [This article is a contribution to the proceedings (to appear in LNP) of the 3rd Baltic RIM Student Seminar (1993). Importance is attached to concrete examples. A more abstract presentation of the ideas underlying this article (including new developments) is found in hep-th/9405110.]
In this note, based on a conference talk, we show how a 3 dimensional topological field theory leads to an algebraic gadget roughly equivalent to a quantum group. This is an expository version of some material in hep-th/9212115 (where we also carry out computations for a specific finite example). We also explain how to incorporate the central extensions usually explained via ``framings'', and we show how to recover invariants of framed tangles. This paper is written using AMSTeX 2.1, which can be obtained via ftp from the American Mathematical Society (instructions included). 2 encapsulated postscript files were submitted separately in uuencoded tar-compressed format.
The heterotic string compactified on an (n-1)-dimensional elliptically fibered Calabi-Yau Z-->B is conjectured to be dual to F-theory compactified on an n-dimensional Calabi-Yau X-->B, fibered over the same base with elliptic K3 fibers. In particular, the moduli of the two theories should be isomorphic. The cases most relevant to the physics are n=2, 3, 4, i.e. the compactification is to dimensions d=8, 6 or 4 respectively. Mathematically, the richest picture seems to emerge for n=3, where the moduli space involves an analytically integrable system whose fibers admit rather different descriptions in the two theories. The purpose of this talk is to review some of what is known and what is not yet known about this conjectural isomorphism. Some of the underlying mathematics of principal bundles on elliptic fibrations is reviewed in the accompanying Taniguchi talk (hep-th/9802094).
Three-dimensional string theories with 16 supersymmetries are believed to possess a non-perturbative U-duality symmetry SO(8,24, Z). By covariantizing the heterotic one-loop amplitude under U-duality, we propose an exact expression for the (∂φ) 4 amplitude, that reproduces known perturbative limits. The weak-coupling expansion in either of the heterotic, type II or type I descriptions exhibits the well-known instanton effects, plus new contributions peculiar to three-dimensional theories, including the Kaluza-Klein 5-brane, for which we extract the summation measure. This letter is a post-scriptum to hep-th/0001083.
Abstract We extend the general method of S.J. Gates Jr. et al. [hep-th/0009192] to compute the consistent gauge anomaly for noncommutative 4d SSYM coupled to chiral matter. The choice of the minimal homotopy path allows us to obtain a simple and compact result. We perform the reduction to components in the WZ gauge proving that our result contains, as lowest component, the bosonic chiral anomaly for noncommutative YM theories recently obtained in literature.