Investigation of the phase structure and excited modes under extremum environment in the strong intaraction

在由量子色动力学(QCD)支配的强相互作用中，夸克之间的张量型四点相互作用通过Nambu-Jana-Lasinio(NJL)模型实现了高重子密度下的夸克-自旋极化。随着夸克数密度的增加，自旋极化发生。然后，双味颜色超导电性就消失了。通过引入夸克间八点相互作用的扩展NJL模型，证明了该模型中存在一个新的相，其中手征对称性恢复，但真空上的基元激发对应于核子。对于纯杨-米尔斯规范理论，在高斯泛函近似下构造了含时变分方法。给出了标量胶球质量和准标量胶球质量，阐明了胶球质量与QCD运行耦合常数和QCD标度参数的关系。

In the strong interaction governed by the quantum chromodynamics (QCD), it has been shown that the quark-spin polarization is realized at high baryon density by using the Nambu-Jana-Lasinio (NJL) model with the tensor-type four-point interaction between quarks. As the quark-number density is increasing, the spin-polarization occurs. Then, the two-flavor color superconductivity disappears. By using the extended NJL model which incorporates the eight-point interaction between quarks, it has been shown that there exists a new phase in this model in which the chiral symmetry recovers but the elementary excitation on the vacuum corresponds to nucleon. For the pure Yang-Mills gauge theory, the time-dependent variational method has been constructed within the Gaussian functional approximation. The scalar and pseudo scalar glueball masses have been given and the dependence of glueball masses on the QCD running coupling constant and QCD scale parameter has been clarified.