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arXiv 0904.2190hep-thastro-ph.COgr-qchep-ph
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无暴胀的Horava-Lifshitz引力的标度不变宇宙学扰动

Scale-invariant cosmological perturbations from Horava-Lifshitz gravity without inflation

Shinji Mukohyama

摘要:

基于Horava最近提出的引力重正化理论,我们提出了一个简单的方案来产生几乎标度不变的超视界曲率扰动。动力学临界指数z=3的各向异性标度意味着在膨胀宇宙的早期产生的自由标量场的量子涨落幅度对哈勃膨胀率不敏感,因此是标度不变的。这些波动后来被曲率机制或/和重粒子/振荡场的调制衰变转换为曲率扰动。例如,这种情况适用于幂律展开a \propto t^p,其中p>1/3,因此不需要暴胀。此外,该方案不依赖于任何附加假设,例如细致平衡条件。

英文摘要:

Based on the renormalizable theory of gravitation recently proposed by Horava, we present a simple scenario to generate almost scale-invariant, super-horizon curvature perturbations. The anisotropic scaling with dynamical critical exponent z=3 implies that the amplitude of quantum fluctuations of a free scalar field generated in the early epoch of the expanding universe is insensitive to the Hubble expansion rate and, thus, scale-invariant. Those fluctuations are later converted to curvature perturbations by the curvaton mechanism or/and the modulated decay of heavy particles/oscillating fields. This scenario works, for example, for power law expansion a\propto t^p with p>1/3 and, thus, does not require inflation. Also, this scenario does not rely on any additional assumptions such as the detailed balance condition.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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