In this work we study different variations of the MIT bag model. We start with the so called non-ideal bag model and discuss it in detail. Then we implement a vector interaction in the MIT bag model that simulates a meson exchange interaction and fix the quark-meson coupling constants via symmetry group theory. At the end we propose an original model, inspired by the Boguta-Bodmer models, which allows us to control the repulsion interaction at high densities. For each version of the model we obtain a stability window as predicted by the Bodmer-Witten conjecture and discuss its thermodynamic consistency.

In the present work we use the modified versions of the MIT bag model, on which both a vector field and a self-interacting term are introduced, to obtain hot quark matter and to investigate the QCD phase diagram. We first analyze two-flavored quark matter constrained to both the freeze-out and the liquid-gas phase transition at the hadronic phase. Later, three-flavored quark matter subject to β equilibrium and charge neutrality is used to compute quark star macroscopic properties, which are confronted with recent observational massive and canonical star radius results. Finally, a comparison with QCD phase diagrams obtained from the Nambu-Jona-Lasinio model is performed.

Using a quantum hadrodynamics (QHD) and MIT based models we construct hybrid stars within the Maxwell criteria of hadron-quark phase transition. We are able to produce a hybrid star with maximum mass of 2.15M⊙. Furthermore, a 2.03M⊙ star with a quark core corresponding to more than $80\%$ of both, its total mass and radius, is also possible.

In this work, we obtain a representation of the QCD phase diagram with the help of two effective models, MIT based bag models to describe quark matter and QHD based models to describe hadronic matter. To obtain the phase transition line, we use the Gibbs conditions that determine the critical chemical potential for symmetric matter at zero and finite temperature.

In this paper, the QCD phase diagram is obtained from the crossing of two effective models: the MIT bag based models are used to describe quark matter and QHD type models to describe hadronic matter. We use the Gibbs' conditions to establish the crossing points of the pressure in function of the chemical potential obtained in both phases. We first analyze two-flavour symmetric matter constrained to both the freeze-out and the liquid-gas phase transition at the hadronic phase. Later we analyse the results for β-stable and charge neutral stellar matter and compare two different prescriptions: one that assumes flavour conservation, so that the quark phase is completely determined from the hadronic phase, and the other based on the Maxwell construction, where the quark phase is also β-stable. At the end, we compute the latent heat to find a signature of the critical end point.