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arXiv 1808.07486astro-ph.COhep-ph
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用CMB探测精细结构常数的空间变化

Probing spatial variation of the fine-structure constant using the CMB

Tristan L. Smith, Daniel Grin, David Robinson, Davy Qi

备注：
21 pages, 11 figures, comments welcome
发表信息：
Phys. Rev. D 99, 043531 (2019)
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摘要：

精细结构常数$α$控制电磁相互作用的强度。在标准模型中，$α$在宇宙长度和时间尺度上是动力学的。宇宙微波背景（CMB）的物理性质取决于$α$的值。$α$的空间变化对CMB的影响与弱透镜效应产生的影响相似：平滑功率谱，产生非高斯特征。这将导致对CMB弱透镜势功率谱估计的偏差。利用这种效应，普朗克测量的温度和偏振功率谱，以及CMB透镜的估计，被用来放置限制（95% C。L.）的范围内。对$α$波动的尺度不变角功率谱相对于$A^α_{\rm SI}\leq 1.6 \times 10^{-5}$的平均值（$C_L^α=A^α_{\rm SI}/[L(L+1)]$）的振幅的影响。极限取决于$α$波动功率谱的假定形状。例如，对于白噪声角功率谱（$C_L^α=A^α_{\rm WN}$），极限为$A^α_{\rm WN}\leq 2.3 \times 10^{-8}$。研究发现，CMB对$α$涨落的响应依赖于一个分离宇宙近似，因此理论预测仅对具有$L\lesssim 100$的$α$多极子是可靠的。可以构建一个最佳的三谱估计，它被发现，它只是稍微比普朗克透镜技术更敏感，但显着更敏感时，考虑到下一代的实验。对于具有宇宙方差有限偏振灵敏度的未来CMB实验（例如，CMB-S4），最优估计量可以用$A^α_{\rm SI}>1.9 \times 10^{-6}$和$A^α_{\rm WN} > 1.4 \times 10^{-9}$检测$α$波动。

英文摘要：

The fine-structure constant, $α$, controls the strength of the electromagnetic interaction. There are extensions of the standard model in which $α$ is dynamical on cosmological length and time-scales. The physics of the cosmic microwave background (CMB) depends on the value of $α$. The effects of spatial variation in $α$ on the CMB are similar to those produced by weak lensing: smoothing of the power spectrum, and generation of non-Gaussian features. These would induce a bias to estimates of the weak-lensing potential power spectrum of the CMB. Using this effect, Planck measurements of the temperature and polarization power spectrum, as well as estimates of CMB lensing, are used to place limits (95% C. L.) on the amplitude of a scale-invariant angular power spectrum of $α$ fluctuations relative to the mean value ($C_L^α=A^α_{\rm SI}/[L(L+1)]$) of $A^α_{\rm SI}\leq 1.6 \times 10^{-5}$. The limits depend on the assumed shape of the $α$-fluctuation power spectrum. For example, for a white noise angular power spectrum ($C_L^α=A^α_{\rm WN}$), the limit is $A^α_{\rm WN}\leq 2.3 \times 10^{-8}$. It is found that the response of the CMB to $α$ fluctuations depends on a separate-universe approximation, such that theoretical predictions are only reliable for $α$ multipoles with $L\lesssim 100$ . An optimal trispectrum estimator can be constructed and it is found that it is only marginally more sensitive than lensing techniques for Planck but significantly more sensitive when considering the next generation of experiments. For a future CMB experiment with cosmic-variance limited polarization sensitivity (e.g., CMB-S4), the optimal estimator could detect $α$ fluctuations with $A^α_{\rm SI}>1.9 \times 10^{-6}$ and $A^α_{\rm WN} > 1.4 \times 10^{-9}$.

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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