Finite-volume and magnetic effects on the phase structure of the three-flavor Nambu–Jona-Lasinio model

• Published in: Physical review. D 2019-04, Vol.99 (7), p.1, Article 076001
• Main Authors: Abreu, Luciano M., Corrêa, Emerson B. S., Linhares, Cesar A., Malbouisson, Adolfo P. C.
• Format: Article
• Language: English
• Subjects: Chemical potential; Constituents; Crossovers; Flavors; Magnetic effects; Magnetic fields; Organic chemistry; Phase transitions; Quarks; Reduction; Solid phases; Thermodynamic properties; Topology
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.99.076001

In this work, we analyze the finite-volume and magnetic effects on the phase structure of a generalized version of Nambu–Jona-Lasinio model with three quark flavors. By making use of mean-field approximation and Schwinger's proper-time method in a toroidal topology with antiperiodic conditions, we investigate the gap equation solutions under the change of the size of compactified coordinates, strength of magnetic field, temperature, and chemical potential. The 't Hooft interaction contributions are also evaluated. The thermodynamic behavior is strongly affected by the combined effects of relevant variables. The findings suggest that the broken phase is disfavored due to both the increasing of temperature and chemical potential and the drop of the cubic volume of size L, whereas it is stimulated with the augmentation of magnetic field. In particular, the reduction of L (remarkably at L≈0.5–3 fm) engenders a reduction of the constituent masses for u,d,s quarks through a crossover phase transition to the their corresponding current quark masses. On the other hand, the presence of a magnetic background generates greater values of constituent quark masses, inducing smaller sizes and greater temperatures at which the constituent quark masses drop to the respective current ones.