ICTP-SAIFR Activities

A hypothetical primordial black hole population may constitute a fraction of dark matter. These black holes can interact and merge, emitting gravitational waves with rates and source properties that differ from those of astrophysical black hole mergers. I will review the collisional processes that drive the formation and coalescence of primordial black hole binaries in the early and late universe. These processes provide key constraints on the merger rates of these binaries and on the contribution of primordial black holes to the dark matter fraction.

"The construction of inflationary models in the context of no-scale supergravity is discussed. The connection between no-scale models and R+R^2 gravity models is emphasized allowing for the construction of Starobinsky-like models of inflation.  Within the context of these models, the process of reheating after inflation is discussed as are mechanisms for the gravitational production of matter."

Quantum Chromodynamics (QCD) is the theory that describes the strong interaction. This interaction, mediated by gluons, is responsible for binding the quarks together to form protons, neutrons and other hadrons, as well as for holding the atomic nuclei together. At high energies, as quarks and gluons interact weakly, perturbation theory is a good tool for analysis. In contrast, the low-energy regime, which is crucial for understanding phenomena such as confinement, cannot be effectively treated with standard perturbative methods, calling for alternative approaches to be understood. In this talk, I will introduce the Curci-Ferrari model in Landau gauge as a framework to access the low-energy regime of QCD. The model modifies the action typically used for high-energy QCD by adding a mass term for the gluon field. This term models the behavior of the gluon propagator in numerical simulations, which behaves similarly to a massive field. The main strength of this model is that it quantitatively reproduces many results of numerical simulations for low-energy QCD, both at zero and at finite temperature and/or density, withminimal modeling. Additionally, the simplicity of the model enables well-controlled approximations that typically yield semi-analytic expressions. In the talk, I will present and discuss some results of the model, focusing on two-, three- and four-point correlation functions as examples of its performance.