Black Objects without a Vacuum

We explore the behavior of gravitational solitons in classical theories with pathological vacua. We first focus on non-tachyonic non-supersymmetric string theories and the construction of brane solutions in the corresponding effective theories, which do not admit a maximally-symmetric vacuum. We then turn to metastable vacua and the holographic interpretation of the vacuum bubbles that may be produced therein by quantum tunneling. Finally, we discuss self-similar collapse solutions, with an eye to analogies with the settings considered in the preceding chapters.