Galilean Genesis: An Alternative to inflation
Galilean Genesis: An Alternative to inflation
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DOI：
10.1088/1475-7516/2010/11/021
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发表时间：
2010-06
影响因子：
6.4
通讯作者：
P. Creminelli;Alberto Nicolis;E. Trincherini
中科院分区：
文献类型：
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作者：
P. Creminelli;Alberto Nicolis;E. Trincherini
我们提出了一个新的宇宙学方案，其中标准的通货膨胀被取代的膨胀阶段与一个激烈的破坏的能量条件（NEC）：>> H2。该模型是基于最近推出的Galileon理论，允许NEC违反解决方案没有不稳定性。未扰动解描述了一个在过去渐近闵可夫斯基的宇宙，随着能量密度的增加而膨胀，直到它退出有效场论的有效范围并重新加热。这个解是一个动力学吸引子，宇宙被驱动到它那里，即使它最初是收缩的。对伽利略场扰动的研究揭示了一些微妙之处，与NEC的严重违反有关，它表明绝热扰动在宇宙学上是无关的。然而，该模型提出了一种新的方法来产生等曲率扰动的标度不变谱，该谱可以在以后转换为绝热的：伽利略子由于对称性而被迫耦合到其他场作为一个标量子;它在NEC破坏解上产生的有效度量是德西特空间的度量，因此所有光标量将自动获得几乎标度不变的扰动谱。
We propose a novel cosmological scenario, in which standard inflation is replaced by an expanding phase with a drastic violation of the Null Energy Condition (NEC): >> H2. The model is based on the recently introduced Galileon theories, which allow NEC violating solutions without instabilities. The unperturbed solution describes a Universe that is asymptotically Minkowski in the past, expands with increasing energy density until it exits the regime of validity of the effective field theory and reheats. This solution is a dynamical attractor and the Universe is driven to it, even if it is initially contracting. The study of perturbations of the Galileon field reveals some subtleties, related to the gross violation of the NEC and it shows that adiabatic perturbations are cosmologically irrelevant. The model, however, suggests a new way to produce a scale invariant spectrum of isocurvature perturbations, which can later be converted to adiabatic: the Galileon is forced by symmetry to couple to the other fields as a dilaton; the effective metric it yields on the NEC violating solution is that of de Sitter space, so that all light scalars will automatically acquire a nearly scale-invariant spectrum of perturbations.