Our universe may have been (or may be) stuck in a metastable state, which can decay to a stable one via tunnelling. Such processes would have triggered observable gravitational waves and require a deeper theoretical understanding. The pioneering paper of Coleman and Callan provided the framework, but an explicit solution was absent. We will discuss a significant improvement of the semi-classical bounce solution and a complete calculation of the one loop correction. These were done via a systematic expansion in the thin wall limit (beyond the usual leading order) and apply to arbitrary spacetime dimension D.
Francesco D'Eramo
