On the critical end point of the QCD and the NJL model phase diagrams

In this talk I compare the knowledge on the critical end point of the QCD phase diagram grasped from lattice calculations, with that obtained from Nambu--Jona-Lasinio (NJL) model computations. The original publication is available at http://www.sif.it/SIF/en/portal/journalsComment: 6 pages, 1 figure. Talk given at IFAE 2009, Bari, 15-17 April 2009. The original publication is available at: http://www.sif.it/SIF/en/portal/journal

Inhomogeneous color superconductivity and the cooling of compact stars

In this talk I discuss the inhomogeneous (LOFF) color superconductive phases of Quantum Chromodynamics (QCD). In particular, I show the effect of a core of LOFF phase on the cooling of a compact star.Comment: 4 pages, 1 figure, uses aiproc style. Talk given at "Quark confinement and the hadron spectrum", Ponta Delgada, Acores, Portugal, 2-7 September 200

Phase diagram and pion modes of the neutral Nambu-Jona Lasinio model with the Polyakov loop

I discuss recent results obtained by our group within the Nambu-Jona Lasinio model with the Polyakov loop. I focus on the two flavor version of the model, discussing the phase diagram in the $\mu-T$ plane in the case in which electrical neutrality is required. One of the results is that pion condensation is not observed in our model when a physical mass for the light quarks is considered.Comment: 6 pages, 3 figures. Invited talk at the YITP international symposium on ``Fundamental Problems in Hot and/or Dense QCD'', Kyoto, Japan, 3-6 Mar 200

The Critical End Point of Quantum Chromodynamics Detected by Chirally Imbalanced Quark Matter

We suggest the idea, supported by concrete calculations within chiral models, that the critical endpoint of the phase diagram of Quantum Chromodynamics with three colors can be detected, by means of Lattice simulations of grand-canonical ensembles with a chiral chemical potential, $\mu_5$, conjugated to chiral charge density. In fact, we show that a continuation of the critical endpoint of the phase diagram of Quantum Chromodynamics at finite chemical potential, $\mu$, to a critical end point in the temperature-chiral chemical potential plane, is possible. This study paves the way of the mapping of the phases of Quantum Chromodynamics at finite $\mu$, by means of the phases of a fictitious theory in which $\mu$ is replaced by $\mu_5$.Comment: List of changes: some reference added; chiral chemical potential better explained. Version to appear on Phys. Rev.

On The Stability of Interpretable Models

Interpretable classification models are built with the purpose of providing a comprehensible description of the decision logic to an external oversight agent. When considered in isolation, a decision tree, a set of classification rules, or a linear model, are widely recognized as human-interpretable. However, such models are generated as part of a larger analytical process. Bias in data collection and preparation, or in model's construction may severely affect the accountability of the design process. We conduct an experimental study of the stability of interpretable models with respect to feature selection, instance selection, and model selection. Our conclusions should raise awareness and attention of the scientific community on the need of a stability impact assessment of interpretable models

Chiral symmetry restoration and deconfinement in strong magnetic fields

I review recent results obtained within chiral effective models, on the phase structure of hot quark matter in a strong magnetic background. After a brief introduction, I focus on the results obtained within two chiral models improved with the Polyakov loop. The models differ for the content of interactions, but both of them are tuned to reproduce Lattice QCD thermodynamics at zero and imaginary chemical potential. One of them takes into account an explicit Polyakov loop dependence of the coupling; the other one neglects this contribution, but takes into account multi-quark interactions. A comparison between the phase diagrams of the two models is presented.Comment: 10 pages, 3 figures, PoS style. Invited talk at "The many faces of QCD, November 2-5, 2010, Gent, Belgium

Diffusion of charm and beauty in the Glasma

Relativistic nuclear collisions offer a unique way to study strong interactions at very high energy. The collision process can be described within the gluon saturation framework as the interaction of two colored glasses, and because of this interaction strong longitudinal gluon fields, namely the Glasma, are produced immediately after the collision. Besides, heavy quarks are also produced in the very early stage and because of their large mass and small concentration, their motion does not affect the evolution of the Glasma, thus behaving as ideal probes of the Glasma itself. We study the evolution of the heavy quarks in the Glasma allegedly produced in high energy p-Pb collisions by solving consistently the equations of motion of the quarks in the evolving Glasma fields. We find that this motion can be understood in terms of diffusion in momentum space, similarly to the random motion of a heavy probe in a hot thermalized medium. We show how the diffusion of heavy probes affects the nuclear modification factor of D and B mesons in p-Pb collisions.Comment: Talk given by M. R. at QCD@Work2018 held in Matera, Italy, 25-28 June 201