Black holes

Finding out what the baby universe may have been up to

Outreach talk for the European Researcher's Night 2021, venetonight at Padova.

Could the black hole singularity be a field singularity?

In the wake of interest to find black hole solutions with scalar hair, we investigate the effects of disformal transformations on static spherically symmetric space-times with a non-trivial scalar field. In particular, we study solutions that have a …

Euclidean gravity

How can bubbles pop out of vacuum? What are the implications for black holes?

Exploring theories of gravity

Is general relativity the theory of gravity?

Thermal activation of thin-shells in anti-de Sitter black hole spacetime

We investigate thermal activation of thin-shells around anti-de Sitter black holes. Under the thin-shell approximation, we extensively study the parameter region that allows a bubble nucleation bounded by a thin-shell out of a thermal bath. We show …

Stationary bubbles: information loss paradox?

The main purpose of this work is to build classically stationary bubbles, within the thin-shell formalism, which are unstable under quantum effects; they either collapse into a black hole or expand. Thus, the final state can be thought of a …

Conformal frames in cosmology

From higher dimensional theories, e.g. string theory, one expects the presence of nonminimally coupled scalar fields. We review the notion of conformal frames in cosmology and emphasize their physical equivalence, which holds at least at a classical …

Stationary bubbles and their tunneling channels toward trivial geometry

In the path integral approach, one has to sum over all histories that start from the same initial condition in order to obtain the final condition as a superposition of histories. Applying this into black hole dynamics, we consider stable and …

Conformal Frame Dependence of Inflation

Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a particular frame, which we call the matter Jordan frame, the matter point …