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arXiv 0711.3602gr-qc
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来自普通流体相互作用的宇宙加速

Cosmic acceleration from interaction of ordinary fluids

Nelson Pinto-Neto, Bernardo M. O. Fraga

备注：
10 pages, no figures, accepted for publication in General Relativity and Gravitation
发表信息：
Gen.Rel.Grav.40:1653-1662,2008
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摘要：

在经典广义相对论的框架下研究了两种相互作用流体的宇宙学模型，每种流体都满足强能量条件。如果相互作用在标度因子中由幂律唯象地描述，则两个初始相互作用流体可以等效地由两个非相互作用有效流体替代，其中一个可以违反强能量条件和/或具有负能量密度。分析解决方案的弗里德曼方程的一般设置获得和研究。取决于相互作用变得重要的尺度，可能有早期加速阶段的非奇异宇宙，或者在大尺度上从减速膨胀过渡到加速膨胀的奇异模型。在第一种模型中，有一些反弹模型，其中收缩被相互作用停止。在第二种情况下，人们得到了没有暗能量的暗能量膨胀率，就像$Λ$ CDM或幻影加速膨胀，分别没有宇宙学常数或幻影。

英文摘要：

Cosmological models with two interacting fluids, each satisfying the strong energy condition, are studied in the framework of classical General Relativity. If the interactions are phenomenologically described by a power law in the scale factor, the two initial interacting fluids can be equivalently substituted by two non interacting effective fluids, where one of them may violate the strong energy condition and/or have negative energy density. Analytical solutions of the Friedmann equations of this general setting are obtained and studied. One may have, depending on the scale where the interaction becomes important, non singular universes with early accelerated phase, or singular models with transition from decelerated to accelerated expansion at large scales. Among the first, there are bouncing models where contraction is stopped by the interaction. In the second case, one obtains dark energy expansion rates without dark energy, like $Λ$CDM or phantomic accelerated expansions without cosmological constant or phantoms, respectively.

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