On a gauge invariant description of soliton dynamics

We present important elements of a gauge and diffeomorphism invariant formulation of the moduli space approximation to soliton dynamics. We argue that explicit velocity-dependent modifications are determined entirely from gauge and diffeomorphism invariance. We illustrate the formalism for the case of a Yang-Mills theory on a curved spacetime background.Comment: 8 pages, contribution to the proceedings of the 35th Ahrenshoop Symposium, 200

Stationary Configurations and Geodesic Description of Supersymmetric Black Holes

This thesis contains a detailed study of various properties of supersymmetric black holes. In chapter I an overview over some of the fascinating aspects of black hole physics is provided. In particular, the string theory approach to black hole entropy is discussed. One of the consequences of the string theory results is that black hole entropy can be understood within the context of an effective field theory only if one resorts to supergravity theories with higher-order curvature interactions. To this extent, some relevant elements of N=2 supersymmetric theories and supergravity theories are introduced in chapter II. In chapter III N=2 supergravity theories with higher-order curvature interactions are described. Chapter IV contains a classification of the fully supersymmetric vacua and a characterization of a large class of stationary BPS black hole configurations in the presence of higher-derivative interactions. In chapter V the derivation of the macroscopic entropy formula appropriate for theories with higher-order curvature interactions is reviewed and compared to the results of string theory. Furthermore, in the absence of higher-order curvature interactions, the metric on the moduli space of simple multi-centered black hole solutions is calculated. In chapter VI, finally, a formalism to derive the geodesic description of generic gravitational solitons is developed

Black hole partition functions and duality

The macroscopic entropy and the attractor equations for BPS black holes in four-dimensional N=2 supergravity theories follow from a variational principle for a certain `entropy function'. We present this function in the presence of R^2-interactions and non-holomorphic corrections. The variational principle identifies the entropy as a Legendre transform and this motivates the definition of various partition functions corresponding to different ensembles and a hierarchy of corresponding duality invariant inverse Laplace integral representations for the microscopic degeneracies. Whenever the microscopic degeneracies are known the partition functions can be evaluated directly. This is the case for N=4 heterotic CHL black holes, where we demonstrate that the partition functions are consistent with the results obtained on the macroscopic side for black holes that have a non-vanishing classical area. In this way we confirm the presence of a measure in the duality invariant inverse Laplace integrals. Most, but not all, of these results are obtained in the context of semiclassical approximations. For black holes whose area vanishes classically, there remain discrepancies at the semiclassical level and beyond, the nature of which is not fully understood at present.Comment: 36 pages, Late

A note on topological amplitudes in hybrid string theory

We study four-dimensional compactifications of type II superstrings on Calabi-Yau spaces using the formalism of hybrid string theory. Chiral and twisted-chiral interactions are rederived, which involve the coupling of the compactification moduli to two powers of the Weyl-tensor and of the derivative of the universal tensor field-strength