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arXiv 0806.1953hep-thastro-ph
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交错多场暴胀

Staggered Multi-Field Inflation

Diana Battefeld, Thorsten Battefeld, Anne-Christine Davis

摘要:

我们研究多场暴胀的情况下,在一个交错的方式退出模型的领域。在弦论的某些多场暴胀体系中,这个特征是很自然的。例如,当场与凝聚的快子相关时,或者当膜湮灭时,膜间距离变得毫无意义时,它就可以显现出来。考虑到一个可分离的潜在的,并促进字段的数量的一个光滑的时间依赖的函数,我们推导出的形式主义来处理这些模型在背景和扰动水平,提供一般表达式的标量谱指数和运行。我们在适当的限度内恢复了例如动态放松的宇宙学常数的已知结果。我们进一步表明,等曲率扰动在通货膨胀期间被抑制,使扰动是绝热的,近高斯。由此产生的结果可以解释为一种新的暖暴胀,在弦论中很容易实现,而且没有暖暴胀的许多缺点。为了验证形式主义的适用性,我们考虑三个具体的模型:一个简单的玩具模型(优雅的退出成为可能),多重快子暴胀(场数量的恒定衰减率和可忽略的慢滚贡献与观测结果非常一致)和M理论中多个M5膜的暴胀(膜的狭窄堆叠产生了一致的场景)。

英文摘要:

We investigate multi-field inflationary scenarios with fields that drop out of the model in a staggered fashion. This feature is natural in certain multi-field inflationary setups within string theory; for instance, it can manifest itself when fields are related to tachyons that condense, or inter-brane distances that become meaningless when branes annihilate. Considering a separable potential, and promoting the number of fields to a smooth time-dependent function, we derive the formalism to deal with these models at the background and perturbed level, providing general expressions for the scalar spectral index and the running. We recover known results of e.g. a dynamically relaxing cosmological constant in the appropriate limits. We further show that isocurvature perturbations are suppressed during inflation, so that perturbations are adiabatic and nearly Gaussian. The resulting setup might be interpreted as a novel type of warm inflation, readily implemented within string theory and without many of the shortcomings associated with warm inflation. To exemplify the applicability of the formalism we consider three concrete models: assisted inflation with exponential potentials as a simple toy model (a graceful exit becomes possible), inflation from multiple tachyons (a constant decay rate of the number of fields and negligible slow roll contributions turns out to be in good agreement with observations) and inflation from multiple M5-branes within M-theory (a narrow stacking of branes yields a consistent scenario).

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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