Noise induced transitions in semiclassical cosmology
Noise induced transitions in semiclassical cosmology
复制标题
半经典宇宙学中的噪声引起的转变
DOI：
10.1103/physrevd.59.083513
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发表时间：
1998
影响因子：
5
通讯作者：
U. Barcelona
中科院分区：
文献类型：
--
作者：
E. Calzetta;Enric Verdaguer Departament de Fisica Fonamental;Institut de F'isica d'Altes Energies;U. Barcelona
考虑了一个半经典宇宙学模型，该模型由一个封闭的Friedmann-Robertson-Walker宇宙学模型和一个无质量、非共形耦合的量子标量场组成。我们证明了量子场的反作用能够驱动宇宙学标度因子越过经典势的势垒，因此，如果宇宙在零标度因子(初始奇点)附近开始，它可以转变到指数膨胀的德西特相。我们计算了这种跃迁的概率，结果证明它与量子宇宙学中宇宙从“零”进入膨胀阶段的概率相当。这表明，在存在物质场的情况下，时空上的反向反应在量子宇宙学中不应被忽视。
A semiclassical cosmological model is considered which consists of a closed Friedmann-Robertson-Walker in the presence of a cosmological constant, which mimics the effect of an inflaton field, and a massless, non-conformally coupled quantum scalar field. We show that the back-reaction of the quantum field, which consists basically of a non local term due to gravitational particle creation and a noise term induced by the quantum fluctuations of the field, are able to drive the cosmological scale factor over the barrier of the classical potential so that if the universe starts near zero scale factor (initial singularity) it can make the transition to an exponentially expanding de Sitter phase. We compute the probability of this transition and it turns out to be comparable with the probability that the universe tunnels from "nothing" into an inflationary stage in quantum cosmology. This suggests that in the presence of matter fields the back-reaction on the spacetime should not be neglected in quantum cosmology.