Long wavelength limit of evolution of nonlinear cosmological perturbations
Long wavelength limit of evolution of nonlinear cosmological perturbations
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非线性宇宙扰动演化的长波长极限
DOI：
10.1103/physrevd.78.103513
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发表时间：
2008
影响因子：
5
通讯作者：
T. Hamazaki
中科院分区：
文献类型：
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作者：
T. Hamazaki
在多重标量场与多重理想流体共存的一般物质组成中，在梯度展开的首阶中，我们构造了局部均匀宇宙非线性演化的所有解.从动量约束出发，我们导出了局部齐次宇宙的解常数必须满足的约束。在空间平坦的Friedmann-Robertson-步行者宇宙中，构造了任意高阶非线性宇宙学微扰理论中的规范不变微扰变量.我们构造了非线性长波极限公式，它表示非线性规范不变微扰变量在局域均匀宇宙演化的微扰下演化的长波极限。利用长波长极限公式，研究了具有任意势的多个慢滚动标量场主导的宇宙中非线性宇宙学扰动的演化。本文引入的$\ensuremath{\tau}$函数和$N$势，使得具有任意相互作用势和任意高阶非线性Barr参数的多个慢滚标量场在慢滚相结束时的演化可以解析地写出.结果表明，慢轧膨胀参数对非线性参数f NL和g NL有抑制作用。
In the general matter composition where the multiple scalar fields and the multiple perfect fluids coexist, in the leading order of the gradient expansion, we construct all of the solutions of the nonlinear evolutions of the locally homogeneous universe. From the momentum constraint, we derive the constraints which the solution constants of the locally homogeneous universe must satisfy. We construct the gauge invariant perturbation variables in the arbitrarily higher order nonlinear cosmological perturbation theory around the spatially flat Friedmann-Robertson-Walker universe. We construct the nonlinear long wavelength limit formula representing the long wavelength limit of the evolution of the nonlinear gauge invariant perturbation variables in terms of perturbations of the evolutions of the locally homogeneous universe. By using the long wavelength limit formula, we investigate the evolution of nonlinear cosmological perturbations in the universe dominated by the multiple slow rolling scalar fields with an arbitrary potential. The $\ensuremath{\tau}$ function and the $N$ potential introduced in this paper make it possible to write the evolution of the multiple slow rolling scalar fields with an arbitrary interaction potential and the arbitrarily higher order nonlinear Bardeen parameter at the end of the slow rolling phase analytically. It is shown that the nonlinear parameters such as ${f}_{\mathrm{NL}}$ and ${g}_{\mathrm{NL}}$ are suppressed by the slow rolling expansion parameters.