CMB quadrupole depression produced by early fast-roll inflation: Monte Carlo Markov chains analysis of WMAP and SDSS data
CMB quadrupole depression produced by early fast-roll inflation: Monte Carlo Markov chains analysis of WMAP and SDSS data
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早期快速暴胀产生的 CMB 四极子凹陷：WMAP 和 SDSS 数据的蒙特卡洛马尔可夫链分析
DOI：
10.1103/physrevd.78.023013
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发表时间：
2008
影响因子：
5
通讯作者：
N. Sanchez
中科院分区：
文献类型：
--
作者：
C. Destri;H. Vega;N. Sanchez
一般来说，经典的暴胀演化在慢滚之前有一个短暂的快滚阶段。在曲率和张量摄动的波动方程中，快滚阶段导致一个纯粹的吸引势（而在慢滚阶段，这个势是纯粹的排斥势）。这种吸引势导致CMB的曲率和b模角功率谱的四极矩下降。在早期宇宙模型中以这种方式出现了一个新的参数：这个吸引势的共动波数k1特征尺度。模态k1恰好在快速滚转到慢滚阶段的过渡阶段退出视界。快滚阶段通过传递函数D(k)动态地修改初始功率谱。我们通过求解膨胀演化方程来计算D(k)。D(k)有效地抑制了k < k1的原始幂，并具有缩放性质D(k) = Ψ（k/ k1），其中Ψ(x)是一个泛函数。我们对WMAP和SDSS数据（包括快速滚动阶段）进行蒙特卡罗马尔可夫链分析，发现k 1 = 0.266 Gpc -1。四极模式k Q = 0.242 Gpc -1比k 1更早退出视界，比快滚结束早约1 / 10 e倍。我们比较了快滚配合与没有快滚配合，但包括对原始功率的一个较低的切断。对于温度-温度模式，温度- E模式和E模式- E模式，快速滚动提供了略好于急剧切断的适合度。此外，我们的拟合提供了r的非零下界，而其他宇宙学参数的值基本上是纯ACDM模型的值。我们展示了实空间两点ctt （θ）相关器。Q在慢滚阶段之前退出视界这一事实意味着在暴胀期间电子折叠总数N的上界。将其与辐射主导时代的估计相结合，我们得到N tot ~ 66，边界62 < N tot < 82。我们用WMAP-5、ACBAR-2007和SDSS数据重复了同样的分析，证实了整体情况。
Generically, the classical evolution of the inflaton has a brief fast-roll stage that precedes the slow-roll regime. The fast-roll stage leads to a purely attractive potential in the wave equations of curvature and tensor perturbations (while the potential is purely repulsive in the slow-roll stage). This attractive potential leads to a depression of the CMB quadrupole moment for the curvature and B-mode angular power spectra. A single new parameter emerges in this way in the early universe model: the comoving wave number k 1 characteristic scale of this attractive potential. This mode k 1 happens to exit the horizon precisely at the transition from the fast-roll to the slow-roll stage. The fast-roll stage dynamically modifies the initial power spectrum by a transfer function D(k). We compute D(k) by solving the inflaton evolution equations. D(k) effectively suppresses the primordial power for k < k 1 and possesses the scaling property D(k) = Ψ(k/k 1 ) where Ψ(x) is a universal function. We perform a Monte Carlo Markov chain analysis of the WMAP and SDSS data including the fast-roll stage and find the value k 1 = 0.266 Gpc ―1 . The quadrupole mode k Q = 0.242 Gpc ―1 exits the horizon earlier than k 1 , about one-tenth of an e-fold before the end of fast roll. We compare the fast-roll fit with a fit without fast roll but including a sharp lower cutoff on the primordial power. Fast roll provides a slightly better fit than a sharp cutoff for the temperature―temperature, temperature― E modes, and E modes― E modes. Moreover, our fits provide nonzero lower bounds for r, while the values of the other cosmological parameters are essentially those of the pure ACDM model. We display the real space two point C TT (θ) correlator. The fact that k Q exits the horizon before the slow-roll stage implies an upper bound in the total number of e-folds N tot during inflation. Combining this with estimates during the radiation dominated era we obtain N tot ∼ 66, with the bounds 62 < N tot < 82. We repeated the same analysis with the WMAP-5, ACBAR-2007, and SDSS data confirming the overall picture.