  We present new solutions of vacuum decay in non-Minkowski spacetimes. On a de
Sitter background, the tunneling between vacuum states with a nonvanishing
energy difference has been considered, whereas in the special case of
degenerate vacua we extended the treatment to a power-law FRW-universe.
Additionally, we dicuss the vacuum decay in static spacetimes. In the case of
Minkowski spacetime, we include interaction with an environmental field and
analyze the effects of decoherence and the quantum-to-classical transition of
the nucleating bubble.

General Relativity and Quantum Cosmology