Multi-field inflation with random potentials: field dimension, feature scale and non-Gaussianity
Multi-field inflation with random potentials: field dimension, feature scale and non-Gaussianity
复制标题
具有随机势的多场膨胀：场维数、特征尺度和非高斯性
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
A. Liddle
中科院分区：
文献类型：
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作者：
J. Frazer;A. Liddle
研究了随机多场势中原始密度微扰的两点关联函数和三点关联函数的超视界演化。我们使用输运方法来演化微扰，并给出可观测的完整演化历史。将单独的宇宙假设确定为类似于光线的几何描述，我们给出了束宽的表达式，从而使我们能够监测朝着绝热极限的演化，并提供了一种理解FNL行为的有用手段。最后，将我们的随机势视为弦景观中通胀的玩具模型，我们通过演变潜力的大量实现的轨迹来构建可观测数据的分布，并对测试此类模型的前景进行了评论。我们发现，在2到6的范围内，可观量的分布对场的数量不敏感，但这些分布对势中特征的尺度高度敏感。对特征尺度最敏感的是光谱指数，在所研究的特征尺度范围内，预测的分散度增加了一个数量级以上。最不敏感的是非高斯性参数FNL，它始终很小；我们没有发现任何有计划的实验能够观察到其非高斯性的实现的例子。
We explore the super-horizon evolution of the two-point and three-point correlation functions of the primordial density perturbation in randomly-generated multi-field potentials. We use the Transport method to evolve perturbations and give full evolutionary histories for observables. Identifying the separate universe assumption as being analogous to a geometrical description of light rays, we give an expression for the width of the bundle, thereby allowing us to monitor evolution towards the adiabatic limit, as well as providing a useful means of understanding the behaviour in fNL. Finally, viewing our random potential as a toy model of inflation in the string landscape, we build distributions for observables by evolving trajectories for a large number of realisations of the potential and comment on the prospects for testing such models. We find the distributions for observables to be insensitive to the number of fields over the range 2 to 6, but that these distributions are highly sensitive to the scale of features in the potential. Most sensitive to the scale of features is the spectral index, with more than an order of magnitude increase in the dispersion of predictions over the range of feature scales investigated. Least sensitive was the non-Gaussianity parameter fNL, which was consistently small; we found no examples of realisations whose non-Gaussianity is capable of being observed by any planned experiment.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.