Melting of scalar mesons and black-hole quasinormal modes in a holographic QCD model

TL;DR

This paper uses a holographic QCD model to study how the gluon condensate influences scalar meson spectra, melting behavior, and black-hole quasinormal modes, revealing temperature-dependent phase transitions and quasiparticle dynamics.

Contribution

It introduces a novel holographic approach linking gluon condensate effects to meson melting and quasinormal mode spectra in a QCD context.

Findings

Gluon condensate affects the confinement/deconfinement transition temperature.

Spectral functions show decreasing quasiparticle peaks with rising temperature.

Scalar quasinormal modes depend on the gluon-condensate parameter.

Abstract

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.