标题： 尺度不变的波动来自伽利略生成模型 显示英文标题

标题： Scale-Invariant Fluctuations from Galilean Genesis

摘要： 我们研究了宇宙涨落谱在诸如加利略创生（Galilean Genesis）等场景中的性质，在这些场景中，一个观测者标量场在早期阶段获得了一种尺度不变的扰动谱，而这个早期阶段在远古时趋近于闵可夫斯基时空。 在引力的最小耦合和标准标量场拉格朗日量的情况下，由该标量场诱导的曲率涨落依赖于标量场的平方，因此是非尺度不变的，并且高度非高斯。 我们证明，如果考虑更高维度算符（即导致膨胀{\eta }-问题的那些算符），背景场与标量场扰动之间会产生线性耦合，从而导致尺度不变且高斯型的曲率涨落。 显示英文摘要

摘要： We study the spectrum of cosmological fluctuations in scenarios such as Galilean Genesis in which a spectator scalar field acquires a scale-invariant spectrum of perturbations during an early phase which asymptotes in the far past to Minkowski space-time. In the case of minimal coupling to gravity and standard scalar field Lagrangian, the induced curvature fluctuations depend quadratically on the spectator field and are hence non-scale-invariant and highly non-Gaussian. We show that if higher dimensional operators (the same operators that lead to the {\eta}-problem for inflation) are considered, a linear coupling between background and spectator field fluctuations is induced which leads to scale-invariant and Gaussian curvature fluctuations.