We compute the masses of even spin glueball states J P C , with P = C = +1, using a twist two operator from an AdS/QCD model known as the hardwall model, using Dirichlet and Neumann boundary conditions. Within this approach, we found that the glueball masses are comparable with those in literature. From these masses, we obtained the Pomeron Regge trajectories for both boundary conditions in agreement with experimental data available and other holographic models.

We study the chiral symmetry breaking and restoration in (2 + 1)-dimensional gauge theories from the holographic hard and softwall models. We describe the behavior of the chiral condensate in the presence of an external magnetic field for both models at finite temperature. For the hardwall model we find Magnetic Catalysis (MC) in different setups. For the softwall model we find Inverse Magnetic Catalysis (IMC) and MC in different situations. We also find for the softwall model a crossover transition from IMC to MC at a pseudocritical magnetic field. This study also shows spontaneous symmetry breaking for both models. Interestingly, for B = 0 in the softwall model we found a nontrivial expectation value for the chiral condensate.

In this work, within an anomalous modified holographic softwall model, we calculate analytically the masses of the scalar glueball with its radial excitations and higher even glueball spin states, with P = C = +1, from a single mass equation. Using this approach we achieved an unified treatment for both scalar and high even spin glueballs masses. Furthermore, we also obtain the Regge trajectory associated with the pomeron compatible with other approaches.

We study the deconfinement phase transition in (2 þ 1)-dimensional holographic SUðNÞ gauge theories in the presence of an external magnetic field from the holographic hard and soft wall models. We obtain exact solutions for the critical temperature of the deconfinement transition for any range of magnetic field. As a consequence, we find a critical magnetic field ðB c Þ, in which the critical temperature ðT c Þ vanishes; for B < B c we have an inverse magnetic catalysis and for B > B c we have a magnetic catalysis.

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