## Glueball and Meson Regge Trajectories From the Gauge/String Correspondence

We use the modern perspective on string theory as being
holographic dual to gauge theories to revisit one of the early successes
of the dual models: being able to describe the Regge trajectories of
hadrons. We identify the classical string configurations in supergravity
backgrounds (KS and MN) dual to confining gauge theories
which correspond to glueballs. Classically, the glueball Regge trajectories
are linear, with zero intercept. By performing a semi-classical analysis
we find that the trajectories become non-linear, with a positive intercept
and positive curvature. When analyzing the string realization of a meson
composed of dynamical quarks in large $N_c$ QCD, we find the emergence of a
valuable phenomenological model of the meson in terms of two rotating
point-like massive particles, connected by a flux tube. The classical Regge
trajectories are non-linear due to the massive "endpoints" of the string.