标题： Cuscuton 回弹的频谱 显示英文标题

标题： Spectrum of Cuscuton Bounce

摘要： 最近的研究表明，基于蔓草引力的宇宙反弹模型不存在鬼场或曲率不稳定性。 我们探讨了蔓草反弹是否可以作为一种替代膨胀机制来产生接近标度不变的标量扰动。 虽然单场蔓草反弹通常会产生强烈的蓝倾斜幂谱（对于各种初始/边界条件），但我们证明，在一个从绝热真空开始且与主要场动能耦合的旁观者场中可以生成标度不变的熵模。 此外，我们的解没有奇点，也不需要人为的匹配条件。 我们还研究了蔓草反弹中张量模（或引力波）的产生，并表明尽管它们是稳定的，与其他反弹模型类似，产生的谱也是强烈的蓝倾斜且不可观测的。 显示英文摘要

摘要： It has been recently shown that a cosmological bounce model based on Cuscuton gravity does not have any ghosts or curvature instabilities. We explore whether Cuscuton bounce can provide an alternative to inflation for generating near scale-invariant scalar perturbations. While a single field Cuscuton bounce generically produces a strongly blue power spectrum (for a variety of initial/boundary conditions), we demonstrate that scale invariant entropy modes can be generated in a spectator field that starts in adiabatic vacuum, and is kinetically coupled to the primary field. Furthermore, our solution has no singularity, nor requires an ad hoc matching condition. We also study the generation of tensor modes (or gravitational waves) in Cuscuton bounce and show that while they are stable, similar to other bounce models, the produced spectrum is strongly blue and unobservable.