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arXiv 1010.5507astro-ph.COhep-th
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暴胀过程中粒子产生的非高斯性

Nongaussianity from Particle Production During Inflation

Neil Barnaby

摘要:

在各种模型中,暴胀子的运动可以在暴胀期间触发一些非暴胀子粒子的产生,例如经由参数共振或相变。这种模型最近引起了人们的兴趣,原因有很多,包括在陡峭的势能上减慢暴胀子运动的可能性。在这篇评论中,我们表明,产生的粒子和暴胀凝聚之间的相互作用,可以导致一个新的机制产生宇宙学的暴胀波动。我们用一个简单的原型模型g^2(λ-λ_0)^2χ^2来说明这种效应,这个模型描述了暴胀子λ和等暴胀子χ之间的相互作用。这种相互作用在超对称性和弦论的各种暴胀模型中是很自然的。利用格点场论模拟和解析计算,我们研究了χ粒子的量子产生及其随后从凝聚态τ(t)中的再散射,从而产生轻暴胀子涨落δ τ的韧致辐射.这种机制导致了原始功率谱中的可观察特征。我们得到这些功能的观测约束,并讨论其影响流行的通货膨胀模型,包括膜/轴子monodromy。暴胀粒子的产生也导致了一种非常新颖的非高斯特征,这种特征可能在未来的任务中被观察到。我们认为,这种机制提供了一个简单的和动机良好的选择,以产生大的非高斯性,没有微调的膨胀轨迹或呼吁重新求和的无限系列的高维算子。

英文摘要:

In a variety of models the motion of the inflaton may trigger the production of some non-inflaton particles during inflation, for example via parametric resonance or a phase transition. Such models have attracted interest recently for a variety of reasons, including the possibility of slowing the motion of the inflaton on a steep potential. In this review we show that interactions between the produced particles and the inflaton condensate can lead to a qualitatively new mechanism for generating cosmological fluctuations from inflation. We illustrate this effect using a simple prototype model g^2 (ϕ-ϕ_0)^2χ^2 for the interaction between the inflaton, ϕ, and iso-inflaton, χ. Such interactions are quite natural in a variety of inflation models from supersymmetry and string theory. Using both lattice field theory simulations and analytical calculations, we study the quantum production of χparticles and their subsequent rescatterings off the condensate ϕ(t), which generates bremsstrahlung radiation of light inflaton fluctuations δϕ. This mechanism leads to observable features in the primordial power spectrum. We derive observational constraints on such features and discuss their implications for popular models of inflation, including brane/axion monodromy. Inflationary particle production also leads to a very novel kind of nongaussian signature which may be observable in future missions. We argue that this mechanism provides a simple and well-motivated option to generate large nongaussianity, without fine-tuning the inflationary trajectory or appealing to re-summation of an infinite series of high dimension operators.

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