Primordial non-Gaussianity from two curvaton decays
Primordial non-Gaussianity from two curvaton decays
复制标题
两个曲线衰减的原始非高斯性
DOI：
10.1103/physrevd.76.103003
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发表时间：
2007
影响因子：
5
通讯作者：
Assadullahi H
中科院分区：
文献类型：
--
作者：
Assadullahi H
我们研究了一个模型，其中两个标量场在暴胀期间是次要的，在暴胀结束后的一段时间内衰变为辐射，但在原始核合成之前。这两个曲率场的扰动可以引起原始曲率扰动。我们在大尺度上写出了原摄动与曲率摄动的完整非线性方程，计算了原摄动的功率谱，最后求出了二阶非线性参数。我们发现，如果曲率的能量密度在它们衰减时是次优的，就像在单曲率的情况下。但我们也发现，当第一个曲率衰减产生的非均匀辐射被第二个几乎均匀的曲率衰减所稀释时，即使曲率占总能量密度的主导地位，也存在较大的能量密度。我们发现最小值min (fNL)=-5/4与单曲率情况相同。
We study a model where two scalar fields, that are subdominant during inflation, decay into radiation some time after inflation has ended but before primordial nucleosynthesis. Perturbations of these two curvaton fields can be responsible for the primordial curvature perturbation. We write down the full nonlinear equations that relate the primordial perturbation to the curvaton perturbations on large scales, calculate the power spectrum of the primordial perturbation, and finally go to second order to find the nonlinearity parameter,. We find large positive values ofif the energy densities of the curvatons are subdominant when they decay, as in the single curvaton case. But we also find a largeeven if the curvatons dominate the total energy density in the case when the inhomogeneous radiation produced by the first curvaton decay is diluted by the decay of a second nearly homogeneous curvaton. The minimum value min(fNL)=-5/4 which we find is the same as in the single-curvaton case.