Inflation with an extra light scalar field after Planck
Inflation with an extra light scalar field after Planck
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普朗克之后的额外光标量场暴胀
DOI：
10.1088/1475-7516/2016/03/024
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发表时间：
2015
影响因子：
6.4
通讯作者：
D. Wands
中科院分区：
文献类型：
--
作者：
V. Vennin;K. Koyama;D. Wands
贝叶斯推理技术用于研究在膨胀和再加热过程中存在额外的轻标量场的情况。这包括（但不限于）曲率型模型。我们设计了一个数值管道，实现了200个膨胀点× 10个再加热场景= 2000个模型，并给出了一些典型电位的结果。我们发现单场模型在引入轻标量自由度时具有显著的鲁棒性。一般来说，在单场水平上被排除在外的模型没有得到改善，因为只有在非常微调的额外场参数值和/或产生大的非高斯性时才能获得良好的光谱指数和张量-标量比。唯一的例外是四次大场暴胀，所以在普朗克之后最好的模型有两种：一种是平台势，不管是否添加了额外的场，另一种是在一些特定的再加热场景下，带有额外的轻标量场的四次大场暴胀。使用贝叶斯复杂度，我们还发现我们研究的模型比它们的单场版本有更多的参数受到约束。这是因为添加的参数不仅对再加热运动学有贡献，而且对宇宙学扰动本身也有贡献，而添加的场对宇宙学扰动也有贡献。这两种效应之间的相互作用导致抑制退化，这是负责有更多的约束参数。
Bayesian inference techniques are used to investigate situations where an additional light scalar field is present during inflation and reheating. This includes (but is not limited to) curvaton-type models. We design a numerical pipeline where ≃ 200 inflaton setups × 10 reheating scenarios = 2000 models are implemented and we present the results for a few prototypical potentials. We find that single-field models are remarkably robust under the introduction of light scalar degrees of freedom. Models that are ruled out at the single-field level are not improved in general, because good values of the spectral index and the tensor-to-scalar ratio can only be obtained for very fine-tuned values of the extra field parameters and/or when large non-Gaussianities are produced. The only exception is quartic large-field inflation, so that the best models after Planck are of two kinds: plateau potentials, regardless of whether an extra field is added or not, and quartic large-field inflation with an extra light scalar field, in some specific reheating scenarios. Using Bayesian complexity, we also find that more parameters are constrained for the models we study than for their single-field versions. This is because the added parameters not only contribute to the reheating kinematics but also to the cosmological perturbations themselves, to which the added field contributes. The interplay between these two effects lead to a suppression of degeneracies that is responsible for having more constrained parameters.
影响因子：
6.5
作者：
Ade, P. A. R.;Aghanim, N.;Zonca, A.
通讯作者：
Zonca, A.
影响因子：
5
作者：
C. Byrnes;Marina Cortês;A. Liddle
通讯作者：
C. Byrnes;Marina Cortês;A. Liddle