In this article,we try to calculate the equation of state(EOS) of quantum chromodynamics(QCD) at finite chemical potential and zero temperature in the framework of a nonperturbative QCD model.Compared with the cold,perturbative EOS of QCD proposed by Fraga et al.,our EOS approaches more fastly to the free quark gas result at large chemical potential.It is expected that our EOS can provide a possible new tool for the study of neutron star.We also try to provide a direct approach for calculating quark number susceptibility and scalar susceptibility at finite chemical potential and zero temperature.
In this letter,we propose to introduce a new Abelian gauge field Bμcorresponding to the so-called β symmetry into the normal Quantum Electrodynamics in 2+1 dimensions(QED3)of γ representation.The resulting theory is shown to be equivalent to QED3 containing two flavors of two-component fermions with mass of an opposite sign.We also show that Bμfield can generate a Chern-Simons term in perturbation theory.A comparison is made between the induced Chern-Simons term in theγrepresentation and that in Pauli representation.
In this paper,we discuss the important role of the thermalization process in the initial distribution of QGP.We find that the negligible heat conduction inside QGP can be expressed as an effective Fourier law and we further analyse qualitatively the results caused by a thermalized initial condition.Based on this arguments,we construct a simple phenomenological model and work with the hydro code,and then we compare our results with the experimental data and the results of the standard initial model.It is found that,as we have argued,a thermalized initial condition suppresses the value of the elliptic flow.
We introduce a pre-hydrodynamic correction to the commonly used Glauber model to bring the random scattering information to the initial condition of the hydrodynamic description for the heavy ion collisions.The results of this correction obviously shrink the value of the elliptic flow in the medium momentum region and move the corresponding momentum of the maximum v 2 forwards to smaller p T value.These fit the experimental data quite well.This correction implies that the quark-gluon plasma(QGP) has reached the thermal equilibrium when the hydrodynamic expansion starts.Such a conclusion of quick-equilibrium confirms the conclusion that QGP is a strongly interacting system.
In this paper,we investigate the behaviors of dual fermion condensate in QED 3 under variation of temperature.By means of Dyson-Schwinger equation for the fermion propagator,we extract the dual fermion condensate and compare its behavior with the ordinary chiral fermion condensate and the chiral susceptibility.It is found that the dual fermion condensate cannot be regarded as the order parameter for the confinement-deconfinement phase transition in QED 3.Furthermore,the change of the dual fermion condensate around the chiral phase transition point observed in the present work must therefore be interpreted as solely induced by the chiral transition.
In this article,we study three types of new Yukawa couplings(the boson field is coupled to the fermion field).Two of them are quadratic Yukawa couplings(the boson field is in the form of a vector),and the other one is the matrix Yukawa coupling(the boson field is in the form of a matrix).Based on the above three couplings,we introduce the Higgs mechanism,and find out the properties of the generated mass for the fermions with multiple flavors.For the matrix boson,we introduce its coupling with non-Abelian gauge field.It turns out that the generated mass of the gauge field through the Higgs mechanism is unique.In the large N limit,using the method of auxiliary field,we study the dynamical behaviors of the quadratic Yukawa couplings,including the poles of some dressed propagators.
The kink structure in the quasiparticle spectrum of electrons in graphene observed at 200 me V below the Fermi level by angle-resolved photoemission spectroscopy（ARPES） was claimed to be caused by a tight-binding electron–phonon（e–ph） coupling in the previous theoretical studies. However, we numerically find that the e–ph coupling effect in this approach is too weak to account for the ARPES data. The former agreement between this approach and the ARPES data is due to an enlargement of the coupling constant by almost four times.
