arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1504.00675astro-ph.COhep-ph
收藏

用宇宙微波背景的谱畸变探测非高斯性的尺度依赖性

Probing the scale dependence of non-Gaussianity with spectral distortions of the cosmic microwave background

Razieh Emami, Emanuela Dimastrogiovanni, Jens Chluba, Marc Kamionkowski

备注：
5 pages, 1 figure
发表信息：
Phys. Rev. D 91, 123531 (2015)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

许多暴胀模型预测原始密度扰动具有非零的三点关联函数，或者傅立叶空间中的双谱。在这种双谱的几种可能性中，最常见的是局部模型双谱，它可以被描述为长波长密度波动对小尺度（大波数）功率谱的空间调制。虽然局部模型预测这种空间调制与尺度无关，但许多变体具有一定的尺度依赖性。在这里，我们注意到，这种规模的依赖性，可以探测与测量的频谱失真的宇宙微波背景（CMB），特别是突出康普顿- $y$失真。波数为$50\,{\rm Mpc}^{-1} \lesssim k \lesssim 10^4\,{\rm Mpc}^{-1}$的原始扰动的耗散会引起化学势（$μ$）畸变，而波数为$1\,{\rm Mpc}^{-1} \lesssim k \lesssim 50\,{\rm Mpc}^{-1}$的原始扰动的耗散会引起康普顿- $y$畸变。利用局部模型非高斯性，可以通过与CMB温度$T$的互相关将这种耗散引起的失真与其他源引起的失真区分开来。我们表明，相对强度的$μT$和$yT$的相关性，从而探测非高斯的尺度依赖性，并估计可能的信号相对于未来实验的灵敏度的大小。我们讨论的互补性，这些测量与其他探头的挤压限制非高斯。

英文摘要：

Many inflation models predict that primordial density perturbations have a nonzero three-point correlation function, or bispectrum in Fourier space. Of the several possibilities for this bispectrum, the most commmon is the local-model bispectrum, which can be described as a spatial modulation of the small-scale (large-wavenumber) power spectrum by long-wavelength density fluctuations. While the local model predicts this spatial modulation to be scale-independent, many variants have some scale-dependence. Here we note that this scale dependence can be probed with measurements of frequency-spectrum distortions in the cosmic microwave background (CMB), in particular highlighting Compton-$y$ distortions. Dissipation of primordial perturbations with wavenumbers $50\,{\rm Mpc}^{-1} \lesssim k \lesssim 10^4\,{\rm Mpc}^{-1}$ give rise to chemical-potential ($μ$) distortions, while those with wavenumbers $1\,{\rm Mpc}^{-1} \lesssim k \lesssim 50\,{\rm Mpc}^{-1}$ give rise to Compton-$y$ distortions. With local-model non-Gaussianity, the distortions induced by this dissipation can be distinguished from those due to other sources via their cross-correlation with the CMB temperature $T$. We show that the relative strengths of the $μT$ and $yT$ correlations thus probe the scale-dependence of non-Gaussianity and estimate the magnitude of possible signals relative to sensitivities of future experiments. We discuss the complementarity of these measurements with other probes of squeezed-limit non-Gaussianity.

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。

↑