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arXiv 0810.4660hep-thastro-phhep-ph
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多场暴胀和宇宙学扰动中的能量转移

Energy Transfer in Multi Field Inflation and Cosmological Perturbations

Amjad Ashoorioon, Axel Krause, Krzysztof Turzynski

摘要:

在级联暴胀和其他一些弦暴胀模型中,可动膜与其他膜或轨道平面的碰撞发生,并导致有趣的宇宙学特征。这些碰撞的基本M/弦理论描述仍然缺乏,但很明显,暴胀子将其部分能量释放到某种形式的膜物质中,例如无张力弦的一个组成部分。在缺乏基本描述的情况下,我们假设膜上有一般的正压流体,它吸收了暴胀子的部分能量。流体由具有适当指数势的标量来模拟,以达到成熟的场论模型。我们数值研究的影响,从暴胀的标量曲率和等曲率扰动的能量转移,并明确表明,曲率功率谱得到调制的振荡阻尼向较小的尺度。尽管等曲率扰动的贡献在暴胀结束时衰减,但它们在碰撞前退出视界的尺度上引起曲率扰动。我们考虑的情况下,标量的行为像辐射,物质或网络的宇宙弦,并讨论所产生的功率谱的差异。

英文摘要:

In cascade inflation and some other string inflation models, collisions of mobile branes with other branes or orbifold planes occur and lead to interesting cosmological signatures. The fundamental M/string-theory description of these collisions is still lacking but it is clear that the inflaton looses part of its energy to some form of brane matter, e.g. a component of tensionless strings. In the absence of a fundamental description, we assume a general barotropic fluid on the brane, which absorbs part of the inflaton's energy. The fluid is modeled by a scalar with a suitable exponential potential to arrive at a full-fledged field theory model. We study numerically the impact of the energy transfer from the inflaton to the scalar on curvature and isocurvature perturbations and demonstrate explicitly that the curvature power spectrum gets modulated by oscillations which damp away toward smaller scales. Even though, the contribution of isocurvature perturbations decays toward the end of inflation, they induce curvature perturbations on scales that exit the horizon before the collision. We consider cases where the scalar behaves like radiation, matter or a web of cosmic strings and discuss the differences in the resulting power spectra.

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