[en] Gauge invariant periodic TDHF solutions are shown to form the same discrete subset of a continuum as would be selected by the Bohr-Sommerfeld quantization condition of the field. Such solutions promise an approximate description for bound eigenstates within the time-dependent framework. Analysis of specific model cases supports the view that this spectrum of gauge invariant periodic TDHF eigensolutions can indeed provide that description. (orig.)

No abstract available

[en] Einstein's theory of gravitation is a geometrical theory, it can however be considered as a gauge theory of the Lorentz group as well. It seems, therefore, to be worthwhile to exhibit the essential geometrical concepts which allow a formulation of gauge theories, of Einstein's gravitational theory, of supergauge theories and of supergravity as well. This common concepts are manifolds, tensor fields, differential forms, exterior derivatives, connection, covariant derivatives, torsion and curvature

[en] We derive the couplings of noncommutative D-branes to spatially varying Ramond-Ramond fields, extending our earlier results in hep-th/0009101. These couplings are expressed in terms of *_n products of operators involving open Wilson lines. Equivalence of the noncommutative to the commutative couplings implies interesting identities as well as an expression for the Seiberg-Witten map that was previously conjectured. We generalise our couplings to include transverse scalars, thereby obtaining a Seiberg-Witten map relating commutative and noncommutative descriptions of these scalars. RR couplings for unstable non-BPS branes are also proposed. (author)

[en] It is often stated in the literature concerning D=4,6 compact Type IIB orientifolds that tadpole cancellation conditions i) uniquely fix the gauge group (up to Wilson lines and/or moving of branes) and ii) are equivalent to gauge anomaly cancellation. We study the relationship between tadpole and anomaly cancellation conditions and qualify both statements. In general the tadpole cancellation conditions imply gauge anomaly cancellation but are stronger than the latter conditions in D=4, N=1 orientifolds. We also find that tadpole cancellation conditions in Z_N D=4,6 compact orientifolds do not completely fix the gauge group and we provide new solutions different from those previously reported in the literature. (author)

[en] We consider a free two-form in six dimensions and calculate the conformal anomaly associated with a Wilson surface observable. (author)

[en] In this paper we investigate the relation between the bulk and boundary in AdS/CFT. We first discuss the relation between the Poincare and the global vacua, and then study various probes of the bulk from the boundary theory point of view. We derive expressions for retarded propagators and note that objects in free fall look like expanding bubbles in the boundary theory. We also study several Yang-Mills theory examples where we investigate thermal screening and confinement using propagators. In the case of confinement we also calculate the profile of a flux tube and provide an alternative derivation of the tension. (author)

[en] In its Euclidean formulation, the AdS/CFT correspondence begins as a study of Yang-Mills conformal field theories on the sphere, S⁴. It has been successfully extended, however, to S¹xS³ and to the torus T⁴. It is natural to hope that it can be made to work for any manifold on which it is possible to define a stable Yang-Mills conformal field theory. We consider a possible classification of such manifolds, and show how to deal with the most obvious objection: the existence of manifolds which cannot be represented as boundaries. We confirm Witten's suggestion that this can be done with the help of a brane in the bulk. (author)

[en] We give a brief review of some of the recent developments in W gravity coupled to matter theories. We then extend the discussion to the case of minimal W conformal field theory, realised in terms of free bosons with background charges, and use this action to investigate some aspects of the anomaly structure and the covariantisation of W gravity. (author). 15 refs, 2 figs

[en] Possible T-violating effects in three-neutrino oscillations in matter are discussed. Simple exact analytical expression for the experimentally measurable quantity of the oscillation probability in matter is derived. Using this expression it is shown that resonant amplification of the T-violating effects takes place. (author) 12 refs., 2 figs