Universal constraints on axions from inflation
Universal constraints on axions from inflation
复制标题
通货膨胀对轴心的普遍约束
DOI：
10.1007/jhep12(2014)139
复制
发表时间：
2014
影响因子：
5.4
通讯作者：
M. Sloth
中科院分区：
文献类型：
--
作者：
R. Z. Ferreira;M. Sloth
我们考虑一个类轴子粒子σ的存在，其一般CP违反轴向耦合的形式为（ασ/f）FF ～ $$ F\tilde{F} $$，其中f μν为一般阿贝珥U(1)规范群的规范场强，与标准电磁无关，f为轴子的衰变常数。先前已经证明，如果轴子与膨胀子相识别，这种相互作用可以导致可测量的宇宙学特征（曲率摄动谱的非高斯修正），这取决于参数ξ=ασ⋅/fH $$ \xi = \alpha \overset{\cdot }{\sigma }/(fH) $$。在本文中，我们将证明，在视界交叉处由于轴耦合而产生的曲率摄动具有一种普遍形式，并且即使轴子σ不与膨胀子一致，在ξ参数方面也保持不变。因此，在不违反观测约束的情况下，通过这种机制产生比真空张量扰动更大的CMB张量扰动似乎是不可能的，除非我们将这种机制与曲率结合起来，或者σ场在暴胀期间变重并衰减。即使在最后一种情况下，也有来自超视界尺度上曲率摄动的慢滚演化的非平凡约束应予以考虑。我们还评论了轴子发挥重要作用的暴胀模型的含义，例如，包括多个轴子的自然暴胀模型和曲率为轴子的模型。
A bstractWe consider the presence of an axion like particle, σ, with a generic CP violating axial coupling of the form (ασ/f)FF˜$$ F\tilde{F} $$, where Fμν is the gauge field strength of a generic abelian U(1) gauge group, not necessarily associated with the standard electromagnetism, and f is the decay constant of the axion. It has previously been demonstrated that if the axion is identified with the inflaton, such an interaction can lead to measurable cosmological signatures (non-Gaussian modifications of the curvature perturbation spectrum) depending on the parameter ξ=ασ⋅/fH$$ \xi = \alpha \overset{\cdot }{\sigma }/(fH) $$. In the present paper we will show that the generation of curvature perturbation at horizon crossing due to the axial coupling has a universal form and remains unmodified in terms of the ξ parameter even if the axion, σ, is not identified with the inflaton. As a consequence, it does not appear to be possible to generate CMB tensor perturbations through this mechanism, larger than the vacuum ones, without violating the observational constraints unless we combine this mechanism with a curvaton or if the σ field becomes heavy and decays during inflation. Even in this last case there are non-trivial constraints coming from the slow-roll evolution of the curvature perturbation on super horizon scales which should be taken into account. We also comment on implications for inflationary models where axions play an important role as, for example, models of natural inflation where more than one axion are included and models where the curvaton is an axion.
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：
8.6
作者：
Ade, P. A. R.;Aikin, R. W.;Yoon, K. W.
通讯作者：
Yoon, K. W.
对齐的自然膨胀：两个轴子的单峰
影响因子：
4.4
作者：
R. Kappl;S. Krippendorf;H. P. Nilles
通讯作者：
H. P. Nilles