论文标题
退化高阶通货膨胀的有效现场理论
Effective field theory of degenerate higher-order inflation
论文作者
论文摘要
我们将通货膨胀的有效场理论扩展到由Arnowitt-Deser-Misner变量构建的一般拉格朗日，该变量涵盖了最通用的相互作用，其背景破坏了时间差异不变性。退化条件，对应于8种不同类型的条件 - 其中一种对应于已知的退化标量探测器模型 - 为在单一仪表中的四次动作级别上以协变量理论中的协变理论中消除了Ostrogradsky Ghost的必要条件。退化的高阶系统对凯奇问题的新颖含义通过显式通货膨胀的相位空间肖像说明了：并非所有的现场配置都会导致对度量的物理解决方案，即使是积极的电位；对于给定配置的解决方案仅是分支选择的独特之处。一个分支上的溶液显然可以在度量的非源点结束，其在替代分支上的延续会导致非弹跳溶液。即使在拉格朗日中的堕落术语是无限的，统一的仪表扰动也可能不稳定。吸引子解决方案导致通货膨胀方案，即使倾斜的慢速参数变化和运行也可能很大，即使潜在的远离通货膨胀结束的电位也没有明确的特征，需要优化的慢速方法来预测可观察到的物品。
We extend the effective field theory of inflation to a general Lagrangian constructed from Arnowitt-Deser-Misner variables that encompasses the most general interactions with up to second derivatives of the scalar field whose background breaks temporal diffeomorphism invariance. Degeneracy conditions, corresponding to 8 distinct types -- only one of which corresponds to known degenerate higher-order scalar-tensor models -- provide necessary conditions for eliminating the Ostrogradsky ghost in a covariant theory at the level of the quadratic action in unitary gauge. Novel implications of the degenerate higher-order system for the Cauchy problem are illustrated with the phase space portrait of an explicit inflationary example: not all field configurations lead to physical solutions for the metric even for positive potentials; solutions are unique for a given configuration only up to a branch choice; solutions on one branch can apparently end at nonsingular points of the metric and their continuation on alternate branches lead to nonsingular bouncing solutions; unitary gauge perturbations can go unstable even when degenerate terms in the Lagrangian are infinitesimal. The attractor solution leads to an inflationary scenario where slow-roll parameters vary and running of the tilt can be large even with no explicit features in the potential far from the end of inflation, requiring the optimized slow-roll approach for predicting observables.
