Cosmology and Effective Field Theory in Warped Extra Dimension

在粒子理论和宇宙学的交叉点上，存在着基本的问题。为什么重力与其他基本力如此不同？为什么它如此薄弱(等级问题)？宇宙的暗能量是什么？是什么推动了通货膨胀，在平滑宇宙的同时播下了结构形成的种子？弦理论和M理论需要额外的空间维度：它们如何解释我们所感知的3D宇宙？最近关于最后一个问题--额外维度--的研究，照亮了所有其他问题。在这个项目中，PI研究了一类额外维度的模型：那些额外维度围绕3-膜扭曲或曲线的模型？一个3D子宇宙困住了普通物质。这种薄膜是由弦和M理论预测的；由于广义相对论，它们扭曲了时空；它们的扭曲使引力和粒子的相互作用都有效地实现了3D。PI的工作使用额外维场理论来校准扭曲的粒子相互作用。因此，电影世界从一个更高的维度预测了一个明确规定的3D宇宙。此外，它们还提供了一种动态降维的方法：由于在扭曲的缺陷--S核上形成了一个巨大的3-膜，相变扭曲了额外维度中的某些场，自发地限制了引力和普通物质。

At the intersection of particle theory and cosmology lie fundamental questions. Why is gravity so different from other fundamental forces? Why is it so weak (the hierarchy problem)? What is the universe's dark energy? What drives inflation, smoothing the universe while seeding structure formation? String and M theories require extra spatial dimensions: how could they explain our perceived 3D universe? Recent work on this last question, extra dimension, illuminates all the others. In this project, the PI investigates a class of extra dimensional models: those where extra dimensions warp, or curve, around a 3-brane ? a 3D sub-universe trapping ordinary matter. Such branes are predicted by string and M theory; they warp space-time, due to general relativity; and their warp renders both gravity and particle interactions effectively 3D. The PI's work calibrates the warped particle interactions, using extra-dimensional field theory. Braneworlds thus predict a well-specified 3D universe, from one of higher dimension. Furthermore, they provide a dynamic means of dimensional reduction: a phase transition twists some field in the extra dimensions, spontaneously confining both gravity and ordinary matter, due to a massive 3-brane formed at the twisting defect?s core.