观察多重宇宙的几率
Odds of observing the multiverse
摘要：
永恒暴胀预测我们的可观测宇宙位于嵌入一定体积的暴胀空间中的气泡（或口袋宇宙）内。气泡的内部经历膨胀和标准宇宙学，而气泡壁向外膨胀并与其他相邻气泡碰撞。碰撞提供了一个直接观察多重宇宙的机会，或者，如果它们产生了不可接受的各向异性，对暴胀理论构成了威胁。在我们的泡泡中，观察者探测到碰撞效应的概率有一个绝对上限，这个上限由我们的泡泡中位于碰撞的前向光锥中的那部分的几率决定;在与相同真空的气泡碰撞的情况下，该界限由气泡成核速率乘以（$H_{\rm{O}}/H_{\rm{I}})^2$，其中$H_{\rm{O}}$是气泡外的哈勃尺度，$H_{\rm{I}}$是气泡内发生的第二轮膨胀的尺度。Freigovel \emph{et al.}用一种不同的方法对具有大得多的宇宙学常数的气泡碰撞的情况得到了类似的结果;这里表明，它在与相同气泡碰撞的情况下也成立。为了得出这个结果，对以前草稿中的一个重大错误进行了更正。
英文摘要：
Eternal inflation predicts our observable universe lies within a bubble (or pocket universe) embedded in a volume of inflating space. The interior of the bubble undergoes inflation and standard cosmology, while the bubble walls expand outward and collide with other neighboring bubbles. The collisions provide either an opportunity to make a direct observation of the multiverse or, if they produce unacceptable anisotropy, a threat to inflationary theory. The probability of an observer in our bubble detecting the effects of collisions has an absolute upper bound set by the odds of being in the part of our bubble that lies in the forward light-cone of a collision; in the case of collisions with bubbles of identical vacua, this bound given by the bubble nucleation rate times ($H_{\rm{O}}/H_{\rm{I}})^2$, where $H_{\rm{O}}$ is the Hubble scale outside the bubbles and $H_{\rm{I}}$ is the scale of the second round of inflation that occurs inside our bubble. Similar results were obtained by Freigovel \emph{et al.} using a different method for the case of collisions with bubbles of much larger cosmological constant; here it is shown to hold in the case of collisions with identical bubbles as well. A significant error in a previous draft was corrected in order to arrive at this result.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
