标题： 双场理论中的宇宙扰动 显示英文标题

标题： Cosmological Perturbations in Double Field Theory

摘要： 我们研究了关于时变（宇宙学）背景的微扰双场理论，直到三阶项。到这个阶数，该理论在弱约束的意义上是一致的，因此对于环面几何结构，它同时编码了动量模式和真正的缠绕模式。我们详细讨论了一致性问题及其解决方法，包括余循环因子的作用以及 $O(d,d,\mathbb{Z})$ 对偶性的作用。最后，作为计算宇宙学相关函数的第一步，我们提出了一个广义的纯量-矢量-张量分解，并用它来构建规范不变的广义巴丁变量。与标准宇宙学相比，这里张量模态较少，而矢量和纯量模态较多。 显示英文摘要

摘要： We explore perturbative double field theory about time-dependent (cosmological) backgrounds to cubic order. To this order the theory is consistent in a weakly constrained sense, so that for a toroidal geometry it encodes both momentum and genuine winding modes. We give a self-contained discussion of the consistency problems and their resolution, including the role of cocycle factors and the $O(d,d,\mathbb{Z})$ duality. Finally, as a first step toward the computation of cosmological correlation functions, we propose a generalized scalar-vector-tensor decomposition and use it to construct gauge invariant generalized Bardeen variables. Compared to standard cosmology there are fewer tensor modes but more vector and scalar modes.