This lecture discusses oscillation modes of stars in Newtonian gravity. These modes are important astrophysical observables. As a particular mechanism to excite the modes, we consider tidal forces raised by a companion star. Such systems can exhibit resonances of oscillations modes and orbital motion. This lecture is based on the first sections of http://arxiv.org/abs/1306.5820 and an outlook to the relativistic case in http://arxiv.org/abs/1304.2228 is given.
The lesson will focus on the quantum theory of perturbations (scalar and tensor) in time evolving background relevant for cosmology. Special emphasis will be put on the individuation of the correct observable quantities, and on aspects and issues of the quantization procedure.
This lecture will give an overview of some models of braneworld in higher dimensional gravity. Higher dimensional gravity emerges from String Theory as a low energy model. The braneworld models we will present here are in some sense phenomenological in the sense that we will use scalar and/or gauge fields with some given potentials in order to support the brane. Although this idea seems to lead to model dependant results, we will see that generic aspects are available. We will start by reviewing the most famous brane models, namely the Randall-Sundrum and Arkani-Hamed-Dimopoulos-Dvali models, which assume thin branes. Next we discuss smoothened thick branes supported by solitonic fields. Finally we briefly explain how to localize fermions on the brane.
I will present an overview of some powerful black hole solution generating techniques in theories of gravity coupled to vector and scalar fields. These methods lead recently to the discovery of novel charged black rings in a five-dimensional Einstein-Maxwell-dilaton theory. Such solutions are expected to be the most general black rings in this theory. Although I will focus on charged black rings, the techniques discussed can be applied in broader contexts. Most of the material presented is available at http://arxiv.org/abs/1305.4969.