Parametric resonance in the early Universe—a fitting analysis
Parametric resonance in the early Universe—a fitting analysis
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DOI：
10.1088/1475-7516/2017/02/001
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发表时间：
2016-09
影响因子：
6.4
通讯作者：
Daniel G. Figueroa;Francisco Torrenti
中科院分区：
文献类型：
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作者：
Daniel G. Figueroa;Francisco Torrenti
在早期宇宙中通过参量共振产生粒子是一种非微扰、非线性和非平衡的现象。虽然这是一个很好的研究课题，每当一个新的情况下表现出参数共振，一个完整的重新分析通常是必要的。为了避免这个繁琐的任务，许多作品往往只提出一个简化的线性处理的问题。为了在未来超越这种情况，我们提供了一个拟合分析的参数共振通过其所有相关阶段：初始线性增长，非线性演化，并放松到平衡。在3+1维的扩展网格中使用晶格模拟，我们参数化了相关成分的动力学结果扫描：振荡场的作用，粒子耦合强度，初始条件和背景膨胀率。我们强调的振荡场的衰减时间的线性计算的不准确性，并提出了一个更合适的定义，这个规模的基础上，随后的非线性动力学。我们提供了简单的适合相关的时间尺度和粒子能量分数在每个阶段。我们的拟合可以应用于暴胀后的预热场景，其中振荡场是暴胀子，或者应用于旁观者场场景，其中振荡场可以是例如弯曲子或标准模型希格斯。
Particle production via parametric resonance in the early Universe, is a non-perturbative, non-linear and out-of-equilibrium phenomenon. Although it is a well studied topic, whenever a new scenario exhibits parametric resonance, a full re-analysis is normally required. To avoid this tedious task, many works present often only a simplified linear treatment of the problem. In order to surpass this circumstance in the future, we provide a fitting analysis of parametric resonance through all its relevant stages: initial linear growth, non-linear evolution, and relaxation towards equilibrium. Using lattice simulations in an expanding grid in 3+1 dimensions, we parametrize the dynamics' outcome scanning over the relevant ingredients: role of the oscillatory field, particle coupling strength, initial conditions, and background expansion rate. We emphasize the inaccuracy of the linear calculation of the decay time of the oscillatory field, and propose a more appropriate definition of this scale based on the subsequent non-linear dynamics. We provide simple fits to the relevant time scales and particle energy fractions at each stage. Our fits can be applied to post-inflationary preheating scenarios, where the oscillatory field is the inflaton, or to spectator-field scenarios, where the oscillatory field can be e.g. a curvaton, or the Standard Model Higgs.