AI 中文总结
研究在紫外完备引力理论中能否实现无鬼和快子不稳定性的反弹解，通过在(1 + 3)形式体系中围绕特定时空分析自由度，发现无负宇宙学常数难以构建无不稳定反弹，还分析了标量和张量模式及相关影响。
AI 中文摘要
解析无穷导数引力理论为协变常数背景周围的引力提供了可重整化且无鬼的描述。这些理论可有无奇异的反弹宇宙解。本文旨在探讨在此框架下能否实现无鬼或快子不稳定性的反弹解。我们在(1 + 3)形式体系中围绕闵可夫斯基和德西特时空对自由度进行详细分析。结果表明，一般而言，没有负宇宙学常数就无法构建无不稳定的反弹。对该模型中已知反弹解的分析表明，高阶导数形状因子的解析性与解参数相结合会导致鬼辐射的出现。受解决宇宙学奇点问题想法的推动，我们仍对标量和张量模式进行分析。标量模式似乎根本不影响宇宙微波背景观测，同时计算了张量模式谱并讨论了相应影响。
英文摘要
Analytic infinite derivative gravity theories provide a renormalizable and ghost-free description of gravity around covariantly constant backgrounds. These theories can have non-singular bouncing Universe solutions. In this paper we aim to address a question whether it is possible to realize a bouncing solution without the presence of a ghost or a tachyon instability in this framework. We perform a detailed analysis of degrees of freedom in $(1+3)$ formalism around Minkowski and de Sitter space-times. As a result it becomes clear that on a very general basis one cannot construct an instability free bounce without a negative cosmological constant. An analysis of known bouncing solutions in this model shows that an analyticity of higher derivative form factors in combination with solutions parameters result in the presence of a ghost radiation. Being motivated by the idea of resolving the cosmological singularity problem we proceed by analyzing scalar and tensor modes anyway. Scalar modes appear to not influence Cosmic Microwave Background observations at all, while tensor modes spectrum is computed and the corresponding implications are discussed.
Comments29 pages
