在(2+1)维手征Gross-Neveu模型中有限温度的顶角修正和退耦合相变

Vertex Correction at Finite Temperature and Decoupling Transition in (2+1) Dimensional Chiral Gross-Neveu Model

本文根据含复合场的Ward-Takahashi恒等式所得到的费米子质量谱,利用虚时温度场论计算了准确到1/N阶的费米子和σ介子的顶角修正。并讨论了顶角函数随温度的变化关系和退耦合相变。结果表明:退耦合相变的临界温度随着零温下π介子和费米子质量的增大而升高,由热涨落对顶角修正所引起的费米子质量的改变不能忽略。

With the aid of imaginary time temperature field theory and fermion mass spectrum derived from Ward-Takahashi identities with composite fields, the vertex correction among fermions and σ meson is calculated beyond the leading order in 1/N expansion, and the change of vertex function with temperature and decoupling transition are discussed in (2+1) dimensional chiral Gross-Neveu model. It turns out that the critical temperature of decoupling transition arises with increasing fermion mass and π meson mass at zero temperature; the vertex correction resulting from thermal fluctuation will affect the fermion dynamical mass and cannot be ignored at finite temperature.