Regge trajectories for mesons in the holographic dual of large-Nc QCD

We discuss Regge trajectories of dynamical mesons in large-Nc QCD, using the supergravity background describing Nc D4-branes compactified on a thermal circle. The flavor degrees of freedom arise from the addition of Nf << Nc D6 probe branes. Our work provides a string theoretical derivation, via the gauge/string correspondence, of a phenomenological model describing the meson as rotating point-like massive particles connected by a flux string. The massive endpoints induce nonlinearities for the Regge trajectory. For light quarks the Regge trajectories of mesons are essentially linear. For massive quarks our trajectories qualitatively capture the nonlinearity detected in lattice calculations