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正是在势能项 <math>V(\phi)</math> 中触发了对称性破缺。例如左图所示的 [[Jeffrey Goldstone]] <ref>{{Cite journal | last1 = Goldstone | first1 = J. | doi = 10.1007/BF02812722 | title = Field theories with " Superconductor " solutions | journal = Il Nuovo Cimento | volume = 19 | issue = 1 | pages = 154–164 | year = 1961 | bibcode = 1961NCim...19..154G | s2cid = 120409034 | url = http://cds.cern.ch/record/343400 }}</ref>给出的势能函数：
正是在势能项 <math>V(\phi)</math> 中触发了对称性破缺。例如左图所示的Jeffrey Goldstone <ref>{{Cite journal | last1 = Goldstone | first1 = J. | doi = 10.1007/BF02812722 | title = Field theories with " Superconductor " solutions | journal = Il Nuovo Cimento | volume = 19 | issue = 1 | pages = 154–164 | year = 1961 | bibcode = 1961NCim...19..154G | s2cid = 120409034 | url = http://cds.cern.ch/record/343400 }}</ref>给出的势能函数：
{{NumBlk|::|<math>V(\phi) = -5|\phi|^2 + |\phi|^4 \,</math>.|{{EquationRef|2}}}}
{{NumBlk|::|<math>V(\phi) = -5|\phi|^2 + |\phi|^4 \,</math>.|{{EquationRef|2}}}}
该势函数具有无穷数量的最小值点（真空态）当
{{NumBlk|::|<math>\phi = \sqrt{5} e^{i\theta} </math>.|{{EquationRef|3}}}}
{{NumBlk|::|<math>\phi = \sqrt{5} e^{i\theta} </math>.|{{EquationRef|3}}}}
for any real ''θ'' between 0 and 2''π''. The system also has an unstable vacuum state corresponding to {{nowrap|1=''Φ'' = 0}}. This state has a [[Unitary group|U(1)]] symmetry. However, once the system falls into a specific stable vacuum state (amounting to a choice of ''θ''), this symmetry will appear to be lost, or "spontaneously broken".
for any real ''θ'' between 0 and 2''π''. The system also has an unstable vacuum state corresponding to {{nowrap|1=''Φ'' = 0}}. This state has a [[Unitary group|U(1)]] symmetry. However, once the system falls into a specific stable vacuum state (amounting to a choice of ''θ''), this symmetry will appear to be lost, or "spontaneously broken".