论文标题
通用缓慢收缩中的源
Sourced fluctuations in generic slow contraction
论文作者
论文摘要
我们为缓慢的收缩宇宙引入了一组通用条件，以及称为快速滚动模型的狭窄模型类别。我们介绍了标量和张量扰动的超级冻结冻结的一般条件，并表明任何快速滚动模型都可以满足它们的满足，例如在通货膨胀的情况下。我们对“来源的弹跳”方案感兴趣，其中扰动是由$ u（1）$ gauge场耦合到保镖标量场的。略带红色倾斜标量光谱的要求极大地限制了标量和量规场之间的允许耦合。我们表明，可行的略带红色标量频谱是可以实现的。但是，在快速滚动近似中，张量表与量表的比率通常是$ r \ simeq 1/9 $，与当前的观测值不一致。我们通过一个明确的例子来证明总体结果，我们将“中间收缩”配音。我们证明，快速滚动的小修改不会改变绿色的功能，并不会导致$ r <0.06 $与数据一致，以超过电子折叠。因此，成功的“弹跳”需要不同的源或与快速滚动的显着偏差。
We introduce a set of generic conditions for the slow contracting Universe and for a narrowed-down category of models called fast-roll models. We present general conditions for super horizon freeze-out of scalar and tensor perturbations and show that any fast-roll model satisfies them, as in the case of inflation. We are interested in the "Sourced Bounce" scenario, where perturbations are sourced by a $U(1)$ gauge field coupled to a bouncer scalar field. The requirement of a slightly red tilted scalar spectrum greatly restricts the allowed couplings between the scalar and the gauge field. We show that a viable slightly red scalar spectrum is achievable. However, within the fast-roll approximation, the tensor-to-scalar ratio is in general $r\simeq 1/9$, inconsistent with current observations. We demonstrate the general result with an explicit example we dub "Intermediate contraction". We prove that small modifications in fast-roll that do not alter the Green's functions do not result in $r<0.06$ consistent with the data for more than an e-fold. Hence, a successful "Sourced Bounce" requires a different source or a significant deviation from fast-roll.
