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arXiv 1306.1262astro-ph.COhep-ph
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宇宙加速立方Galileon模型的参数空间

The parameter space of Cubic Galileon models for cosmic acceleration

Emilio Bellini, Raul Jimenez

摘要:

我们使用最近的测量宇宙的膨胀历史的立方Galileon模型的参数空间上的限制,特别是我们集中在这些模型中包含最简单的Galileon项加上线性潜力。这对这些模型的拉格朗日量给出了强约束。伽利略拉格朗日量中的大多数动力学项被约束为小的,并且加速度有效地由标量势中的常数项提供,从而有效地减少到用于当前加速度的LCDM模型。有效状态方程与宇宙学常数w = -1的状态方程是不可区分的,并且数据约束它没有超过百分之几水平的时间变化。伽利略的能量密度只能贡献大约10%的加速能量密度,其余90%是宇宙学常数项。这证明了直接测量宇宙的膨胀历史在限制暗能量的动力学性质方面是多么有用。

英文摘要:

We use recent measurements of the expansion history of the universe to place constraints on the parameter space of cubic Galileon models, in particular we concentrate on those models which contain the simplest Galileon term plus a linear potential. This gives strong constraints on the Lagrangian of these models. Most dynamical terms in the Galileon Lagrangian are constraint to be small and the acceleration is effectively provided by a constant term in the scalar potential, thus reducing, effectively, to a LCDM model for current acceleration. The effective equation of state is indistinguishable from that of a cosmological constant w = -1 and the data constraint it to have no temporal variations of more than at the few % level. The energy density of the Galileon can contribute only to about 10% of the acceleration energy density, being the other 90% a cosmological constant term. This demonstrates how useful direct measurements of the expansion history of the universe are at constraining the dynamical nature of dark energy.

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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