混合试探作用量对三维格点规范场的研究

Phase Diagrams of Lattice Gauge Theories with Mixed Trial Action in Three Dimensions

应用混合元格变量—链变量作用量作为改进平均场理论的试探作用量,用变分法计算了3维时空中Z(2),U(1)和SU(2)纯格点规范场的平均元格内能Ep.对于Z(2)格点规范场得出具有范德瓦尔斯型曲线的一级相变的相图.对于3维U(1)和SU(2)规范场,所得Ep～β曲线是光滑的,显示理论的禁闭性.计算结果与MC 计算结果符合较好.

Using mixed plaquette variable-link variable action as a trial actionof modified mean field theory,we calculate the mean plaquette energies Ep ofpure Z(2),U(1)and SU(2)lattice gauge fields in three dimensions.Phasediagram of first order phase transition of Van der Waals' curve like is obtainedforZ(2)group and the results cannot be derived with any other trial actions.TheEp—β curves for 3-D U(1)and SU(2)group are smooth,showing only a single,confining phase.The results from strong-coupling region to crossover region candescribe the phase structure well and are in good agreement with the MonteCarlo results.