标题： 引力扰动的反作用问题 显示英文标题

标题： On the Back Reaction Problem for Gravitational Perturbations

摘要： 我们推导了宇宙扰动的有效能动张量，并证明了它的规范不变性。 这一结果被用于研究扰动对暴胀宇宙中弗里德曼背景行为的影响。 我们发现，宇宙扰动对背景的反作用在低于自繁殖尺度的能量上就已经可能变得重要。 显示英文摘要

摘要： We derive the effective energy-momentum tensor for cosmological perturbations and prove its gauge-invariance. The result is applied to study the influence of perturbations on the behaviour of the Friedmann background in inflationary Universe scenarios. We found that the back reaction of cosmological perturbations on the background can become important already at energies below the self-reproduction scale.