Angelo Caravano

• PhD student
• PhD Student at Ludwig-Maximilians-Universität in Munich

We use a lattice simulation to study a model of axion inflation where the inflaton is coupled to a U(1) gauge field through Chern-Simons interaction. These kinds of models have already been studied with a lattice simulation in the context of reheating. In this work, we focus on the deep inflationary phase and discuss the new aspects that need to be...

If gauge fields are coupled to an axion field during inflation, they lead to unique observational signatures within the reach of next generation experiments. However, this system often shows strong backreaction effects, invalidating the standard perturbation theory approach. In this paper, we present the first nonlinear lattice simulation of inflat...

The scalar field theory of cosmological inflation constitutes nowadays one of the preferred scenarios for the physics of the early universe. In this paper we aim at studying the inflationary universe making use of a numerical lattice simulation. Various lattice codes have been written in the last decades and have been extensively used for understat...

Ghost-free bimetric theory describes two nonlinearly interacting spin-2 fields, one massive and one massless, thus extending general relativity. We confront bimetric theory with observations of Supernovae type 1a, Baryon Acoustic Oscillations and the Cosmic Microwave Background in a statistical analysis, utilising the recently proposed physical par...

In this thesis I provide an overview on the Electroweak interaction from a theoretical and phenomenological point of view. First, I describe the first experiments that led to the discovery of Weak interaction and the first theoretical models. The aim of the rest of the thesis is to explain this interaction in the wider context of the Standard Model...

A spectator axion-gauge sector, minimally coupled to the inflaton, with the axion experiencing a momentary stage of fast roll during cosmological inflation, can generate unique signatures in primordial density fluctuations and the gravitational wave background. We present the first lattice simulation of this system using a novel hybrid numerical sc...

Violating the slow-roll regime during the final stages of inflation can significantly enhance curvature perturbations, a scenario often invoked in models producing primordial black holes and small-scale scalar induced gravitational waves. When perturbations are enhanced, one approaches the regime in which tree-level computations are insufficient, a...

For the first time, we investigate the nonperturbative dynamics of single field inflation with a departure from slow roll. Using simulations, we find that oscillatory features in the potential can drastically alter the course of inflation, with major phenomenological implications. In certain cases, the entire Universe gets trapped in a forever infl...

We introduce the Parity-Odd Power (POP) spectra, a novel set of observables for probing parity violation in cosmological N-point statistics. POP spectra are derived from composite fields obtained by applying nonlinear transformations, involving also gradients, curls, and filtering functions, to a scalar field. This compresses the parity-odd trispec...

A spectator axion-gauge sector, minimally coupled to the inflaton, with the axion experiencing a momentary stage of fast roll during cosmological inflation, can generate unique signatures in primordial density fluctuations and the gravitational wave background. We present the first lattice simulation of this system using a novel hybrid numerical sc...

We introduce the Parity-Odd Power (POP) spectra, a novel set of observables for probing parity violation in cosmological $N$-point statistics. POP spectra are derived from composite fields obtained by applying nonlinear transformations, involving also gradients, curls, and filtering functions, to a scalar field. This compresses the parity-odd trisp...

We present the first nonlinear lattice simulation of an axion field coupled to a U(1) gauge field during inflation. We use it to fully characterize the statistics of the primordial curvature perturbation ζ. We find high-order statistics to be essential in describing non-Gaussianity of ζ in the linear regime of the theory. On the contrary, non-Gauss...

We present a nonlinear study of the inflationary epoch based on numerical lattice simulations. Lattice simulations are a well-known tool in primordial cosmology, and they have been extensively used to study the reheating epoch after inflation. We generalize this known machinery to the inflationary epoch. Being this the first simulation of the infla...

We use a non-linear lattice simulation to study a model of axion inflation where the inflaton is coupled to a U(1) gauge field through Chern-Simons interaction. This kind of models have already been studied with a lattice simulation in the context of reheating. In this work, we focus on the deep inflationary phase and discuss the new aspects that n...

The scalar field theory of cosmological inflation constitutes nowadays one of the preferred scenarios for the physics of the early universe. In this paper we aim at studying the inflationary universe making use of a numerical lattice simulation. Various lattice codes have been written in the last decades and have been extensively used for understat...

Ghost-free bimetric theory describes two nonlinearly interacting spin-2 fields, one massive and one massless, thus extending general relativity. We confront bimetric theory with observations of Supernovae type 1a, Baryon Acoustic Oscillations and the Cosmic Microwave Background in a statistical analysis, utilising the recently proposed physical par...

Report of a full-time internship of 5 months at Institute Astrophysique de Paris (IAP). The goal of the internship was to develop a numerical simulation for the geometrical destabilization of inflation.

A Statistical Physics approach to Modern Coding Theory and XORSAT problems.

After the indication of an enhanced Gamma-ray flux from the Crab nebula by Gasparrini et al. (ATel#5971) we observed the Crab with the 30cm telescope of the Foligno Observatory with a Canon 350D (scale 0.89 arcsec/pixel). We obtained two series of unfiltered images, each with 15 minutes exposure. The pulsar was detected just separated from the brig...

We performed BV photometry of the transient source MASTER OTJ204200.48+041839.9 We found a blue color B-V=0.2, and a fast flux decline >0.4 mag/day. Also an archive objective prism spectrum in the Digitized First Byurakan Survey taken in 1973 shows the source in a high state with a blue color.

We followed in the V band the flare of ASASSN-13ae in 2013. The light curve shape is in agreement with that of a previous burst in 2007, and suggestive of a CV of WZ Sge type with recurrence of 5.9 years. A search for short-term periodicity over 3 hours on MJD 56421 gave no results at 0.03 mag level.

We performed a follow-up observation of the OT J211322.92+260647.4, referred in ATel #4675, with the 30cm F/10 Schmidt-Cassegrain telescope of the Foligno Observatory in the V filter and 900 s exposure. Aperture photometry was made with IRAF-apphot using as reference 143 stars brighter than V=15.5 from the UCAC catalogue in our field of view. The c...