Spectator field dynamics in de Sitter and curvaton initial conditions
Spectator field dynamics in de Sitter and curvaton initial conditions
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德西特和 Curvaton 初始条件下的观察场动力学
DOI：
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发表时间：
2012
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通讯作者：
A. Tranberg
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作者：
K. Enqvist;R. Lerner;Olli Taanila;A. Tranberg
研究了膨胀过程中光观标量场长波模式的随机行为。当从经典场值出发时，观众的概率分布既向外扩散，又向平衡分布移动。我们研究了二次和四次混合势的时标。平衡的时间尺度取决于模型的参数，并且可能惊人地大，对于大多数轻型观众来说超过数千倍。这些结果表明，在膨胀过程中，观众场的初始条件不会自动消除。这些一般结果可以用来确定宇宙大小的补丁内零模式值的概率，这与观测有关。作为一个例子，我们将结果应用于曲率模型来计算曲率摄动的概率分布，并讨论了“典型”宇宙。
We investigate the stochastic behaviour of long wavelength modes of light spectator scalar fields during inflation. When starting from a classical field value, the probability distribution for the spectator both spreads out and moves towards an equilibrium distribution. We study the timescales for a mixed quadratic and quartic potential. The timescale of equilibration depends on the parameters of the model, and can be surprisingly large, more than thousands of e-folds for the majority of light spectators. These results imply that the initial conditions for spectator fields are not automatically erased during inflation. These general results can be used to determine the probability of the value of the zero-mode inside a Universe-sized patch, which is relevant for observations. As an example, we apply the results to the curvaton model to calculate the probability distribution of the curvature perturbation and discuss 'typical' Universes.