A three fluid system describing the decay of the curvaton is studied by numerical and analytical means. We place constraints on the allowed interaction strengths between the fluids and initial curvaton density by requiring that the curvaton decays before nucleosynthesis while nucleosynthesis, radiation-matter equality and decoupling occur at correct temperatures. We find that with a continuous, time-independent interaction, a small initial curvaton density is naturally preferred along with a low reheating temperature. Allowing for a time-dependent interaction, this constraint can be relaxed. In both cases, a purely adiabatic final state can be generated, but not without fine-tuning. Unlike in the two fluid system, the time-dependent interactions are found to have a small effect on the curvature perturbation itself due to the different nature of the system. The presence of non-gaussianity in the model is discussed.
Non-Gaussianity of the primordial perturbation in the curvaton model
我们使用Δ N -形式主义来研究结构起源的曲率场景中原始曲率扰动的非高斯性。我们数值计算的全概率分布函数，允许的曲率的非瞬时衰减，并比较这与突然衰减近似的分析结果。我们还提出了结果的领导秩序的贡献，原始的双谱和三谱。在突然衰减近似中，我们导出了一个完全非线性的表达原始扰动的初始曲率扰动。作为一个例子，如何非高斯提供额外的约束模型参数，我们展示了如何原始的双谱CMB尺度可以用来约束方差在曲率场的小得多的尺度。我们的分析和数值计算结果允许原始非高斯性的多个测试，因此，他们可以提供曲率的情况下的一致性测试。
Correlated isocurvature perturbations from mixed inflaton-curvaton decay
我们研究宇宙学扰动的情况下，目前的物质由暴胀和曲率衰变产物的混合物。我们计算如何曲率扰动转移到它的衰变产物在一般情况下，当它不像灰尘的行为。考虑到暴胀子的衰变产物也可以有扰动，结果是相关绝热扰动和等曲率扰动的有趣混合。特别是，负相关可以通过降低Sachs-Wolfe平台中的角功率而不改变峰结构来改善对CMB数据的拟合。我们对WMAP数据进行了11参数拟合。我们发现，最佳拟合不是“和谐模型”，以及拟合模型不集群周围的最佳拟合，使宇宙学参数不能可靠地估计。我们还发现，在我们的模型中，平均四极（l=2）功率为l（l+1）C_l/2 pi = 1081 μ K ^2，远低于纯绝热LCDM模型中的1262 μ K ^2。
