论文标题
过山车宇宙学
Rollercoaster Cosmology
论文作者
论文摘要
（删节）通货膨胀是否必须一次发生？答案是肯定的！所有宇宙学问题都可以通过一系列短的宇宙加速度爆发来解决，并被简化的膨胀时期短时代中断。如果最后一个$ {\ cal o}（50） - {\ cal o}（60）$ efolds至少是$ {\ cal o}（15）$ efolds，则扰动的频谱仍然与CMB和LSS相匹配。其他阶段可能要短得多。但是，只要它们加起来高达$ {\ cal o}（50） - {\ cal o}（60）$ efolds，而它们之间的减速扩张的阶段则较短，总体上也较少，随后的宇宙学将通过Muster。中断的存在重置了每个加速阶段的厄折时钟，并在CMB枢轴点更改其值。这种变化打开了理论空间，松开了界限。特别是，一些模型似乎排除在$ {\ cal n} = 60 $的较短阶段，$ {\ cal n} = 30 $非常适合。有趣的预测是，扰动的标量和张量光谱在短波长下迅速修改。这些特征可以通过未来的CMB光谱搜索和短波长原始重力探针进行测试。这些模型中的空间曲率可能大于最大的波长标量扰动，因为$ω_ {\ tt k} $的演变方式不同于标量扰动$ \ frac {Δρ}ρ| _ {\ tt s} $。最后，在许多较短的加速扩张阶段，从以前的加速阶段重新加热的产品并没有完全消除。这意味着宇宙可能包含其他粒子种群，比可见的颗粒更罕见，甚至是在上次再加热之前在后期减速时期产生的原始黑洞，这可能是暗物质。
(Abridged) Does inflation have to happen all in one go? The answer is a resounding no! All cosmological problems can be solved by a sequence of short bursts of cosmic acceleration, interrupted by short epochs of decelerated expansion. The spectrum of perturbations will still match the CMB and LSS if the earliest stage of the last ${\cal O}(50)-{\cal O}(60)$ efolds is at least ${\cal O}(15)$ efolds long. Other stages can be considerably shorter. But as long as they add up to ${\cal O}(50)-{\cal O}(60)$ efolds and the stages of decelerated expansion in between them are shorter and also overall last less, the ensuing cosmology will pass muster. The presence of the interruptions resets the efold clock of each accelerating stage, and changes its value at the CMB pivot point. This change opens up the theory space, loosening the bounds. In particular some models that seem excluded at ${\cal N}=60$ fit very well as shorter stages with ${\cal N}=30$. Interesting predictions are that both the scalar and tensor spectra of perturbations are rapidly modified at short wavelengths. These features could be tested with future CMB spectroscopy searches and with short wavelength primordial gravity probes. The spatial curvature in these models can be larger than the largest wavelength scalar perturbations, because $Ω_{\tt k}$ evolves differently than the scalar perturbations $\frac{δρ}ρ|_{\tt S}$. Finally, with many short stages of accelerated expansion, the abundance of reheating products from previous accelerated stages does not get completely wiped out. This implies that the universe may contain additional populations of particles, more rare than the visible ones, or even primordial black holes, created during a late decelerated epoch before last reheating, which may be dark matter.
