Anisotropic power-law k-inflation
Anisotropic power-law k-inflation
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各向异性幂律 k 暴胀
DOI：
10.1103/physrevd.88.103517
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发表时间：
2013
影响因子：
5
通讯作者：
Shinji Tsujikawa
中科院分区：
文献类型：
--
作者：
Junko Ohashi;Jiro Soda;Shinji Tsujikawa
众所周知，幂律k-暴胀可以在拉格朗日量中实现，其中是标量场的动能，是关于（是常数，是约化普朗克质量）的任意函数。在存在与暴胀子指数耦合的矢量场的情况下，我们证明了具有拉格朗日的模型一般会产生各向异性的暴胀解，其中是各向异性剪切，是各向同性膨胀率。只要这些各向异性解存在于比率远小于1的区域中，则它们是稳定的吸引子，而与形式无关。我们将我们的结果应用到具体的k-膨胀模型，如广义的非线性鬼凝聚和Dirac-Born-Infeld模型，我们数值计算表明，不同的初始条件下的解决方案收敛到各向异性幂律膨胀吸引子。即使在de Sitter极限（）中，这样的解也可以存在，但在这种情况下，零能量条件通常被违反。后者的性质是一致的沃尔德的宇宙猜想，说明各向异性的头发不生存的德西特背景下的存在的问题尊重占主导地位/强能量的条件。
It is known that power-law k-inflation can be realized for the Lagrangian, whereis the kinetic energy of a scalar fieldandis an arbitrary function in terms of(is a constant andis the reduced Planck mass). In the presence of a vector field coupled to the inflaton with an exponential coupling, we show that the models with the Lagrangiangenerally give rise to anisotropic inflationary solutions with, whereis an anisotropic shear andis an isotropic expansion rate. Provided these anisotropic solutions exist in the regime where the ratiois much smaller than 1, they are stable attractors irrespective of the forms of. We apply our results to concrete models of k-inflation such as the generalized dilatonic ghost condensate and the Dirac-Born-Infeld model and we numerically show that the solutions with different initial conditions converge to the anisotropic power-law inflationary attractors. Even in the de Sitter limit () such solutions can exist, but in this case the null energy condition is generally violated. The latter property is consistent with the Wald’s cosmic conjecture stating that the anisotropic hair does not survive on the de Sitter background in the presence of matter respecting the dominant/strong energy conditions.