The results indicate that in the two-dimensional case U(1) symmetry is not broken but in the three-dimensional case a clear evidence of spontaneous breaking of the U(1) symmetry is observed in the weak coupling region.

• 结果表明；对二维情况不存在U(1)对称性的自发破缺；对三维情况；在弱耦合区看到了明显的U(1)对称性的自发破缺.