论文标题
用$ p（x，ϕ）$自调和宇宙常数的宇宙常数
Self-tuning of the cosmological constant in brane-worlds with $P(X,ϕ)$
论文作者
论文摘要
我们重新审视将观察到的宇宙常数自我调整为消失的价值的想法，并将其提升为Brane-World模型的选择标准，在该标准中，我们的宇宙用嵌入5D体积中的3个体系描述。作为一个具体设置，我们考虑了一般lagrangian $ p（x，ϕ）$的批量标量字段$ ϕ $，带有$ x = - （\ partialϕ）^2/2 $。通过要求该模型强制执行最大对称的3-Brane世界体积的4D曲率，以独立于4D有效的真空能量消失，只有两个可能性仍然存在：一个可能性存在：一个具有规范的体积动力学术语，另一个具有与Cuscuton场类似的非常简短的体积动力学术语。进一步要求缺乏散装奇异性，后者被选为模型类别中的独特可能性。在背景级别上，该解决方案可以容纳任何具有散装奇异性的扭曲因子轮廓，并且具有有限的有效4D Planck质量。在宇宙学的背景下，我们的解决方案将在后期描述我们的（几乎）平坦的宇宙，并且预期在宇宙膨胀稀释之前，预计将通过宇宙的演变来确定散装的扭曲因子。最终，在散装中进行了简单的分析，在背景解决方案周围没有明显的不稳定。考虑到Brane弯曲模式是必不可少的，并且需要进行全面的稳定性分析，但仍留下来进行以后的工作。
We revisit the idea of self-tuning the observed cosmological constant to a vanishing value and promote it to a selection criterion of brane-world models, in which our Universe is described by a 3-brane embedded in a 5d bulk. As a concrete setup, we consider a bulk scalar field $ϕ$ described by a general Lagrangian $P(X,ϕ)$ with $X=-(\partialϕ)^2/2$. By requiring that the model enforces the 4d curvature of the maximally symmetric 3-brane world-volume to vanish independently of the 4d effective vacuum energy, only two possibilities remain: one with a canonical bulk kinetic term and the other with an unconventional bulk kinetic term similar to a Cuscuton field. Further demanding the absence of bulk singularity, the latter is selected as a unique possibility within the class of models. At the background level, the solution can accommodate any warp factor profile free from bulk singularity and with a finite effective 4d Planck mass. In a cosmological context, our solution would describe our (almost) flat Universe at late times, with a bulk warp factor profile expected to be determined by the evolution of the Universe before dilution of the matter fields by cosmic expansion. Eventually, a simple analysis is performed in the bulk showing no obvious instability around the background solution. A full stability analysis taking into account brane bending modes is nevertheless necessary and left for future work.
