线缺陷

本书暂定概念：尚未进入正式概念库。下面是本书给出的定义原文。

定义 · 4.8 凝聚态系统中的序

若系统处于非均匀态，则梯度自由能不能忽略，$\psi$ 可能不再取值于 $M$ 中。不过，如果序参量变化的特征尺度远大于相干长度，我们仍可假定序参量取值于 $M$ 中，只是此时其取值是位置的函数。在这种情况下，介质中可能存在一些点、线或面，序参量在其上没有唯一的定义。它们称为缺陷(defect)。按维数可分为点缺陷(point defect)（单极子）、线缺陷(line defect)（涡旋）和面缺陷(surface defect)（畴壁）。这些缺陷由同伦群来分类。

英文原文

If the system is in an inhomogeneous state, the gradient free energy cannot be negligible and $\psi$ may not be in $M$ . If the characteristic size of the variation of the order parameter is much larger than the coherence length, however, we may still assume that the order parameter takes its value in $M$ , where the value is a function of position this time. If this is the case, there may be points, lines or surfaces in the medium on which the order parameter is not uniquely defined. They are called the defects. We have point defects (monopoles), line defects (vortices) and surface defects (domain walls) according to their dimensionalities. These defects are classified by the homotopy groups.

出处：4.8 凝聚态系统中的序 · node a-957ddaebe35cc55ff9ca2f98 · 源节点 SHA-256 14963764fdd93567…