Inflationary potentials in DBI models
Inflationary potentials in DBI models
复制标题
DBI 模型中的通货膨胀潜力
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
K. Tzirakis
中科院分区：
文献类型：
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作者：
D. Bessada;W. Kinney;K. Tzirakis
本文研究了DBI膨胀的一般模型，该模型的特征为幂函数流参数和声速c_S(Phi)，其中α和β分别为常数。结果表明，在慢滚极限下，根据α和β之间的关系以及暴胀场的时间演化，这个一般模型产生了不同的暴胀类，每个暴胀类对应一个特定的势，特别是我们发现在这个非正则模型中还出现了著名的正则多项式(大场和小场)、混合势和指数势。我们发现这些非正则类与它们的正则类似物具有相同的物理特征，不同之处在于膨胀子场随声速的变化而演化；此外，我们还证明了一大类正则和D膜膨胀模型是这种一般非正则模型的特例。接下来，我们将大场多项式模型的预报与当前的观测数据进行了比较，发现低声速的模型具有红移的标量谱，且张量标量比较低，与观测值吻合较好。这些模型还显示了大非高斯性与低张量幅度之间的相关性，这是DBI膨胀与大场多项式势的明显特征。
We study DBI inflation based upon a general model characterized by a power-law flow parameter $\epsilon(\phi)\propto\phi^{\alpha}$ and speed of sound $c_s(\phi)\propto\phi^{\beta}$, where $\alpha$ and $\beta$ are constants. We show that in the slow-roll limit this general model gives rise to distinct inflationary classes according to the relation between $\alpha$ and $\beta$ and to the time evolution of the inflaton field, each one corresponding to a specific potential; in particular, we find that the well-known canonical polynomial (large- and small-field), hybrid and exponential potentials also arise in this non-canonical model. We find that these non-canonical classes have the same physical features as their canonical analogs, except for the fact that the inflaton field evolves with varying speed of sound; also, we show that a broad class of canonical and D-brane inflation models are particular cases of this general non-canonical model. Next, we compare the predictions of large-field polynomial models with the current observational data, showing that models with low speed of sound have red-tilted scalar spectrum with low tensor-to-scalar ratio, in good agreement with the observed values. These models also show a correlation between large non-gaussianity with low tensor amplitudes, which is a distinct signature of DBI inflation with large-field polynomial potentials.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.
影响因子：
5
作者：
R. Bean;Xingang Chen;H. Peiris;Jiajun Xu
通讯作者：
R. Bean;Xingang Chen;H. Peiris;Jiajun Xu