Vacuum decay is a prominent example of strongly nonlinear effects in quantum field theory with potentially important implications for cosmology, relating to phase transitions in the early universe or the supposed metastability of the current Higgs vacuum. Although a general theoretical description was laid out in the 80s by Sidney Coleman and his collaborators, fundamental questions pertaining to the back-reaction of true vacuum bubbles on space-time curvature and their correlations remain so far unanswered, calling for different approaches to the problem.

Black holes appear to lead to information loss, thus violating one of the fundamental tenets of Quantum Mechanics. Recent Information-Theory-based arguments imply that information loss can only be avoided if at the scale of the black hole horizon there exists a structure (commonly called fuzzball or firewall) that allows information to escape. I will discuss the highly-unusual properties that this structure must have and how these properties emerge in the realization of this structure in String Theory via branes, fluxes and topology.

In this talk I will demonstrate how, by introducing additional scalar degrees of freedom, one can measure properties of the inflationary era which may be otherwise inaccessible. Using two explicit examples (the curvaton and a feebly interacting model of dark matter), which introduce new informative priors into the post-inflationary phenomenology, we are able to constrain either the total duration that inflation takes place or its energy scale independently of the tensor-to-scalar ratio.

Higgs Inflation is no doubt one of the most favoured models of inflation in present time. But the huge non-minimal coupling of the Higgs field with gravity required for the model to work often raises concern which is dubbed as the 'unitarity problem' of Higgs inflation. We will show that CSL-like collapse dynamics, otherwise applied to inflationary dynamics in order to explain the quantum-to-classical transition of primordial quantum modes, can bring down the value of non-minimal coupling considerably.

The inflationary paradigm is the most successful model for the
generation of primordial perturbations. These perturbations have a
purely quantum origin, while the inhomogeneities and anisotropies
observed today exhibit a classical behavior. The model called Continuous
Spontaneous Localization (CSL) is a proposed mechanism to solve the
measurement problem in quantum mechanics. In this presentation, we will
analyze the theoretical predictions resulting from incorporating the CSL