Thermodynamic Geometry of Nambu -- Jona Lasinio model

The formalism of Riemannian geometry is applied to study the phase transitions in Nambu -Jona Lasinio (NJL) model. Thermodynamic geometry reliably describes the phase diagram, both in the chiral limit and for finite quark masses. The comparison between the geometrical study of NJL model and of (2+1) Quantum Chromodynamics at high temperature and small baryon density shows a clear connection between chiral symmetry restoration/breaking and deconfinement/confinement regimes

Deconfinement transition effects on cosmological parameters and primordial gravitational waves spectrum

The cosmological evolution can be described in terms of directly measurable cosmological scalar parameters (deceleration q, jerk j, snap s, etc⋯) constructed out of high order derivatives of the scale factor. Their behavior at the critical temperature of the quantum chromodynamics (QCD) phase transition in early universe could be a specific tool to study the transition, analogously to the fluctuations of conserved charges in QCD. We analyze the effect of the crossover transition from quarks and gluons to hadrons in early universe on the cosmological scalars and on the gravitational wave spectrum, by using the recent lattice QCD equation of state and including the electroweak degrees of freedom. Near the transition the cosmological parameters follow the behavior of QCD trace anomaly and of the speed of sound of the entire system. The effects of deconfinement turn out to be more relevant for the modification of the primordial spectrum of gravitational waves rather than for the evolution of the cosmological parameters. Our complete analysis, based on lattice QCD simulations and on the hadron resonance gas below the critical temperature, refines previous results

Suspended fixed points

We study the orientifold of the N=1 superconformal field theories describing D3-branes probing the Suspended Pinch Point singularity, as well as the orientifolds of non-chiral theories obtained by a specific orbifold Zn of SPP. We find that these models realize a mechanism analogous to the one recently found for the orientifold of the complex Calabi-Yau cone over the Pseudo del Pezzo surface PdP3c: they all flow to a new IR fixed point such that the value of the a-charge is less than half the one of the oriented theory. We also find that the value of a coincides with the charge of specific orientifolds of the toric singularities L(n¯,n¯,n¯) with n¯=3n/2 for n even or L(n¯,n¯+1,n¯) with n¯=(3n−1)/2 for n odd, suggesting the existence of an IR duality

Mass deformations of unoriented quiver theories

We study the interplay between mass deformations and unoriented projections of super-conformal quiver gauge theories resulting from D3-branes at (toric) Calabi-Yau singularities. We focus on simple orbifold cases (C-3/Z(3) and C-3/Z(4)) and their non-orbifold descendants. This allows us to generalize the construction rules and clarify points that have been previously overlooked. In particular we spell out the conditions of anomaly cancellations as well as super-conformal invariance that typically require the introduction of flavour branes, which in turn may spoil toric symmetry. Finally, we discuss duality cascades in this context and the interplay between Seiberg/toric duality and unoriented projection with (or without) mass deformations