  A holographic model for QCD is employed to investigate the effects of the
gluon condensate on the spectrum and melting of scalar mesons. We find the
evolution of the free energy density with the temperature, and the result shows
that the temperature of the confinement/deconfinement transition is sensitive
to the gluon-condensate parameter. The spectral functions (SPFs) are also
obtained and show a series of peaks in the low-temperature regime, indicating
the presence of quasiparticle states associated to the mesons, while the number
of peaks decreases with the increment of the temperature, characterizing the
quasiparticle melting. In the dual gravitational description, the scalar mesons
are identified with the black-hole quasinormal modes (QNMs). We obtain the
spectrum of QNMs and the dispersion relations corresponding to the scalar-field
perturbations of the gravitational background, and find their dependence with
the gluon-condensate parameter.
