B-mode Polarization in Einstein-Aether Theory
B-mode Polarization in Einstein-Aether Theory
复制标题
爱因斯坦以太理论中的 B 模式偏振
DOI：
10.1103/physrevd.84.084051
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发表时间：
2011
影响因子：
5
通讯作者：
Tsutomu Kobayashi
中科院分区：
文献类型：
--
作者：
Masahiro Nakashima;Tsutomu Kobayashi
利用Einstein-aether理论研究了修正引力场中动力学矢量自由度对CMB模偏振的影响。在这个理论中，矢量扰动可以由暴胀产生，它可以在随后的时期中以超视界尺度增长，从而在CMB模式偏振上留下印记。我们推导出线性微扰方程的协变形式，并计算CMB模式的偏振使用修改的CAMB代码，以便纳入以太矢量场的影响。我们发现，从以太场的模式信号的振幅可以大于从暴胀引力波的贡献合理的初始条件和一个可行的范围内的模型参数，其中微扰模式超光速传播。我们还给出了一个分析参数解释的紧耦合近似的基础上的频谱的形状。
We study how the dynamical vector degree of freedom in modified gravity affects the CMB-mode polarization in terms of the Einstein-aether theory. In this theory, vector perturbations can be generated from inflation, which can grow on superhorizon scales in the subsequent epochs and thereby leaves imprints on the CMB-mode polarization. We derive the linear perturbation equations in a covariant formalism, and compute the CMB-mode polarization using the CAMB code modified so as to incorporate the effect of the aether vector field. We find that the amplitude of the-mode signal from the aether field can be larger than the contribution from the inflationary gravitational waves for reasonable initial conditions and for a viable range of model parameters, in which perturbation modes propagate superluminally. We also give an analytic argument explaining the shape of the spectrum based on the tight coupling approximation.