论文标题
在具有二等限制的模型中自发对称性破坏
Spontaneous symmetry breaking in models with second-class constraints
论文作者
论文摘要
在这项工作中，探索了具有二等约束的某些非线性理论中的自发对称性破坏。使用Dirac的方法，我们对自由度的约束和计数进行分析。相应的有效哈密顿式的构造是明确构建的。结果表明，在有效的哈密顿量采用临界值的表面上，象征结构变成退化。特别是，我们证明，在自发对称性破裂的条件下，这意味着非微不足道的真空表面，二等限制在相位空间的某些区域上表现为一流的限制，从而导致不确定的狄拉克的支架以及自由度的修改。由于身体上的结果，这些模型可能会遭受某些病理的影响，例如具有可aus典繁殖的模式的存在。详细描述了这种现象发生的具体示例。
In this work the spontaneous symmetry breaking in certain nonlinear theories with second-class constraints is explored. Using the Dirac's method we perform an analysis of the constraints and the counting of the degrees of freedom. The corresponding effective Hamiltonian is constructed explicitly. It is shown that on the surfaces where the effective Hamiltonian takes critical values the symplectic structure becomes degenerate. In particular, we demonstrate that under the condition of spontaneous symmetry breaking, which implies non trivial vacuum surfaces, second-class constraints behave as first-class ones on certain regions of the phase space, leading to undefined Dirac's brackets and to the modification of the number of degrees of freedom. As a physical consequence, these models can suffer from certain pathologies such as the existence of modes with an acausal propagation. Concrete examples where this phenomena occurs are described in detail.
