QCD phase structure from holographic models

We aim to study the effects of chemical potential and angular velocity on the critical endpoint of quantum chromodynamics (QCD). We used several probes (drag force, jet quenching parameter, heavy vector meson spectral function) to characterize the phase transition and studied gravitational waves from the holographic QCD phase transition in the early universe. We used different holographic QCD models to discuss the QCD phase transition, energy loss, spectral function, and gravitational waves. We found that the chemical potential and angular velocity changed the location of the critical endpoint, and the drag force and jet quenching parameter were temperature dependent and enhanced near the phase transition temperature. The magnetic field had a nontrivial effect on the spectral function. We conclude that the chemical potential decreases ωc, and the angular velocity decreases µc and the phase transition temperature. The jet quenching parameter and drag force can characterize the phase transition, and the magnetic field promotes the dissociation of heavy vector mesons. Moreover, the energy density of gravitational waves decreases as the gluon condensate increases, and the peak frequency shifts downward with increasing gluon condensate.Exploring the phase structure of QCD is an important task in high-energy heavy ion collision physics, and recently, there has been considerable interest in the QCD phase transition for rotating backgrounds.