Study On Phase Transition In Holographic Quantum Chromodynamics

The strong interaction,which is one of the four fundamental interactions,emerges when the scale of human exploration becomes smaller and smaller,until it touches the structure of the atomic nucleus.The fact that nucleons can be bound to form atomic nuclei tells us that the strong force is far greater than the electromagnetic force.Deep inelastic experiments have confirmed the correctness of the quark model and quantum chromodynamics(QCD)to a certain extent,which,as the basic theory describing the strong interaction,give a basic description of the interaction between quarks and gluons.We know that quantum chromodynamics has asymptotic free properties at the high energy end,and the current perturbative quantum field theory method can well handle the quantum chromodynamics problem at the high energy end,but due to the strong coupling property of quantum chromodynamics at low energy scales,We need to develop non-perturbative methods to help us gain a deep understanding of low-energy strong interaction physics.Among them,the QCD phase transition and QCD thermodynamics involved in our research are one of the important issues of lowenergy QCD.To understand the collective thermal motion properties of hadrons,we need to explore and apply new non-perturbative methods.Our work builds a low-energy QCD phenomenological model based on the holographic duality principle(AdS/CFT),and is concerned with the connection between the chiral phase transition and the deconfinement phase transition in the QCD phase transition,and the influence of the magnetic field on the QCD phase transition.Our work Based on the improved soft-wall AdS/QCD model established previously.The problems analyzed in the two works are different,and the background geometry and model action are naturally different.It can be found that when the coupling of the background field and the material field is considered,the chiral and deconfinement phase transition behaviors are consistent;in addition,we find that the magnetic field is chiral.The phase transition and muon melting behavior have an inverse magnetic catalysis(IMC)effect.The first chapter of this paper briefly introduces the principle of AdS/CFT duality,and also gives a brief overview of AdS space-time and black hole thermodynamics,indicates the space-time background geometry under our work,and also introduces the development of the AdS/QCD model.In the second chapter,we propose an improved soft wall model for the relationship between chirality and deconfinement phase transition,introduce the background geometry and model action,and obtain the corresponding state equation and The variation behavior of chiral condensation with temperature is analyzed.Different five-dimensional scalar dual operator dimension Δ,different coupling constantβ,and phase transition behavior under chiral limit and finite quark mass are analyzed.In the third chapter,under the background geometry of adding a magnetic field,the behavior of the chiral phase transition and the spectral function of the meson are analyzed.melting behavior.Our work examines specific QCD thermodynamic properties,which contribute to our insight and understanding of the non-perturbative properties associated with QCD phase transitions.