Cosmological Perturbations Through a Simple Bounce
Cosmological Perturbations Through a Simple Bounce
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DOI：
10.1103/physrevd.70.063515
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发表时间：
2004-04
影响因子：
5
通讯作者：
L. Allen;D. Wands
中科院分区：
文献类型：
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作者：
L. Allen;D. Wands
我们提出了一个简单的标量场模型，产生非奇异宇宙学解的研究。我们研究了均匀和各向同性背景的定性动力学和非均匀线性扰动的演化。我们计算了在坍缩阶段从小尺度上的初始真空涨落产生的超哈勃尺度上的扰动谱，然后通过反弹数值地演化这些扰动谱。我们表明，在崩溃阶段计算的共动曲率扰动提供了一个很好的估计所产生的大尺度绝热扰动在膨胀阶段，而Barket规势是由什么成为一个衰减模式反弹后占主导地位。我们证明了尺度因子与（−t）2/3成比例的幂律坍缩相可以在膨胀相中产生绝热标量扰动的尺度不变谱，但是张量扰动的幅度对允许的初始条件有重要的限制。
We present a study of a simple scalar field model that yields non‐singular cosmological solutions. We study both the qualitative dynamics of the homogeneous and isotropic background and the evolution of inhomogeneous linear perturbations. We calculate the spectrum of perturbations generated on super‐Hubble scales during the collapse phase from initial vacuum fluctuations on small scales and then evolve these numerically through the bounce. We show that the comoving curvature perturbation calculated during the collapse phase provides a good estimate of the resulting large scale adiabatic perturbation in the expanding phase while the Bardeen metric potential is dominated by what becomes a decaying mode after the bounce. We show that a power‐law collapse phase with scale factor proportional to (−t)2/3 can yield a scale‐invariant spectrum of adiabatic scalar perturbations in the expanding phase, but the amplitude of tensor perturbations places important constraints on the allowed initial conditions.