Cosmology in generalized Proca theories
Cosmology in generalized Proca theories
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DOI：
10.1088/1475-7516/2016/06/048
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发表时间：
2016-03
影响因子：
6.4
通讯作者：
A. D. Felice;Lavinia Heisenberg;R. Kase;S. Mukohyama;S. Tsujikawa;Ying-li Zhang
中科院分区：
文献类型：
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作者：
A. D. Felice;Lavinia Heisenberg;R. Kase;S. Mukohyama;S. Tsujikawa;Ying-li Zhang
我们考虑一个大质量的矢量场的导数相互作用，传播只有3个所需的极化（除了两个张量极化重力）与二阶运动方程在弯曲的时空。这种广义Proca理论的宇宙学意义的背景和线性微扰的研究，考虑到拉格朗日五阶。在存在的物质流体的时间分量的矢量场，我们推导出的背景运动方程，并显示存在的deSitter解决方案有关的晚时间宇宙加速。我们还获得了鬼和拉普拉斯不稳定性的张量，矢量和标量扰动的小尺度限制的情况下的条件。我们的结果被应用到具体的例子中的一般功能的理论，其中包括矢量Galileons作为一个特定的情况。在这样的例子中，我们证明了德西特不动点总是一个稳定的吸引子，并研究可行的参数空间，在宇宙膨胀的历史中，无鬼和稳定性条件得到满足。
We consider a massive vector field with derivative interactions that propagates only the 3 desired polarizations (besides two tensor polarizations from gravity) with second-order equations of motion in curved space-time. The cosmological implications of such generalized Proca theories are investigated for both the background and the linear perturbation by taking into account the Lagrangian up to quintic order. In the presence of a matter fluid with a temporal component of the vector field, we derive the background equations of motion and show the existence of de Sitter solutions relevant to the late-time cosmic acceleration. We also obtain conditions for the absence of ghosts and Laplacian instabilities of tensor, vector, and scalar perturbations in the small-scale limit. Our results are applied to concrete examples of the general functions in the theory, which encompass vector Galileons as a specific case. In such examples, we show that the de Sitter fixed point is always a stable attractor and study viable parameter spaces in which the no-ghost and stability conditions are satisfied during the cosmic expansion history.