标题： 避免由圆形电流承载宇宙弦环崩塌 显示英文标题

标题： Avoidance of Collapse by Circular Current-Carrying Cosmic String Loops

摘要： 早期尝试计算 Witten 型超导真空涡旋缺陷的非线性动力学演化时，依赖的是过于简单的近似导电弦模型，这些模型无法充分考虑电流饱和效应的影响。 然而，这种效应在最近发展的一类更为复杂但仍然方便解析的导电弦模型中得到了充分反映。 拉森和阿克塞尼德斯最近利用这些更现实的模型来研究在角动量不存在的情况下圆弦环的塌缩。 本文的工作将这一研究扩展到一般情况下的圆弦环，即存在角动量的情况，因此会出现离心势垒。 这个势垒会阻止塌缩，除非初始条件使得相关的电流饱和限制得以实现，在这种情况下，涡旋缺陷的弦描述将会失效，因此其后续命运难以预见。 另一方面，如果避免了饱和现象，人们预计该环最终会辐射掉多余的能量并进入一种类似于 vorton 的平衡状态。 显示英文摘要

摘要： Earlier attempts to calculate the nonlinear dynamical evolution of Witten type superconducting vacuum vortex defects relied on the use of approximate conducting string models that were too simple to take proper account of the effect of current saturation. This effect is however allowed for adequately in a newly developed class of rather more complicated, though still conveniently analytic, conducting string models. These more realistic models have recently been employed by Larsen and Axenides for investigating the collapse of circular string loops in the case for which angular momentum is absent. The present work extends this investigation to the generic case of circular string loops for which angular momentum is present, so that there will be a centrifugal potential barrier. This barrier will prevent collapse unless the initial conditions are such that the relevant current saturation limit is attained, in which case the string description of the vortex defect will break down, so that its subsequent fate is hard to foresee. On the other hand if saturation is avoided one would expect that the loop will eventually radiate away its excess energy and settle down into a vorton type equilibrium state.