论文标题
从弯曲场空间中的$ P（x）$的部分紫外线完成
Partial UV Completion of $P(X)$ from a Curved Field Space
论文作者
论文摘要
$ k $ - 效果理论是一种典型的标量场模型，它们已经提供了丰富的现象学，并且已经成为宇宙学广泛研究的目标。众所周知，换档对称$ k $ - essence在平面对称配置中遭受了苛性形成，唯一的例外是规范和dbi-/cuscuton-type动力学术语。考虑到这一点，我们寻求在本文中寻求多场腐蚀性的一般类型$ k $ - essence模型的完整。紫外线理论中的田间空间是自然弯曲的，我们将曲率的规模引入了控制重场质量的参数，该参数将在EFT还原过程中积分。通过数值方法，我们证明了重场的引入确实可以通过在可能的苛性形成附近调用其运动来解决苛刻的问题。我们进一步研究模型的宇宙学应用。通过扩展相对于场空间的曲率量表的方程，我们证明了通过在背景和扰动中取得无限曲率的极限，成功完成了EFT降低，并包括重力。下一个领先的计算始终进行，并表明降低的EFT减少在消失的扰动速度的极限下分解。
The $k$-essence theory is a prototypical class of scalar-field models that already gives rich phenomenology and has been a target of extensive studies in cosmology. General forms of shift-symmetric $k$-essence are known to suffer from formation of caustics in a planar-symmetric configuration, with the only exceptions of canonical and DBI-/cuscuton-type kinetic terms. With this in mind, we seek for multi-field caustic-free completions of a general class of shift-symmetric $k$-essence models in this paper. The field space in UV theories is naturally curved, and we introduce the scale of the curvature as the parameter that controls the mass of the heavy field(s) that would be integrated out in the process of EFT reduction. By numerical methods, we demonstrate that the introduction of a heavy field indeed resolves the caustic problem by invoking its motion near the would-be caustic formation. We further study the cosmological application of the model. By expanding the equations with respect to the curvature scale of the field space, we prove that the EFT reduction is successfully done by taking the limit of infinite curvature, both for the background and perturbation, with gravity included. The next leading-order computation is consistently conducted and shows that the EFT reduction breaks down in the limit of vanishing sound speed of the perturbation.
