ournal of C osmology and A stroparticle hysics Multi-field inflation with random potentials: field dimension, feature scale and non-Gaussianity
ournal of C osmology and A stroparticle hysics Multi-field inflation with random potentials: field dimension, feature scale and non-Gaussianity
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宇宙学和粒子物理学杂志具有随机势的多场膨胀：场维数、特征尺度和非高斯性
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通讯作者：
J. Dipersio
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作者：
A. Ghobadi;Matthew S. Holt;Julie K. Ritchey;J. Dipersio
。我们探索了随机生成的多场势中原始密度扰动的两点和三点相关函数的超视界演化。我们使用传输方法来演化扰动并给出可观测值的完整演化历史。将单独的宇宙假设识别为类似于光线的几何描述，我们给出了束宽度的表达式，从而使我们能够监测绝热极限的演化，并提供理解 f NL 中的行为的有用方法。最后，将我们的随机势视为弦景观中通货膨胀的玩具模型，我们通过演化大量实现势的轨迹来构建可观测值的分布，并对测试此类模型的前景进行评论。我们发现可观测量的分布对 2 到 6 范围内的场数不敏感，但这些分布对势特征的规模高度敏感。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，预测的离散度增加了一个数量级以上。最不敏感的是非高斯参数 f NL ，它一直很小；我们没有发现任何计划的实验能够观察到其非高斯性的实现例子。
. 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 f NL . 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 f NL , which was consistently small; we found no examples of realisations whose non-Gaussianity is capable of being observed by any planned experiment.