论文标题
多场Cuscuton宇宙学
Multi-field Cuscuton Cosmology
论文作者
论文摘要
在本文中，我们首先在弯曲的田间空间歧管中引入了多场Cuscuton重力设置。然后，我们表明该模型允许定期弹跳宇宙学，并且不会在扰动水平上导致鬼魂或其他不稳定性。更准确地说，通过将标量场扰动分解为与背景场空间轨迹相对于切向和正常组件，垂直于背景轨迹的熵模式是健康的，这直接取决于田间空间的特征，而与背景轨迹相切，与背景轨迹的触觉轨迹相加。与配备有额外动力学标量字段的标准Cuscuton理论类似，绝热场没有其自身的动力学，但是它在我们的情况下修改了其他动态场（例如熵模式）的动力学。最后，我们对模型进行了哈密顿分析，以计算动态场传播的自由度。
In this paper, we first introduce a multi-field setup of Cuscuton gravity in a curved field space manifold. Then, we show that this model allows for a regular bouncing cosmology and it does not lead to ghosts or other instabilities at the level of perturbations. More precisely, by decomposing the scalar fields perturbations into the tangential and normal components with respect to the background field space trajectory, the entropy mode perpendicular to the background trajectory is healthy which directly depends on the signature of the field-space metric, whereas the adiabatic perturbation tangential to the background trajectory is frozen. In analogy with the standard Cuscuton theory equipped with an extra dynamical scalar field, the adiabatic field does not have its own dynamics, but it modifies the dynamics of other dynamical fields like entropy mode in our scenario. Finally, we perform a Hamiltonian analysis of our model in order to count the degrees of freedom propagated by dynamical fields.
