We study the covariance in the angular power spectrum estimates of CMB fluctuations when the primordial fluctuations are non-Gaussian. The non-Gaussian covariance comes from a nonzero connected four-point correlation function – or the trispectrum in Fourier space – and can be large when long-wavelength (super-CMB) modes are strongly coupled to short-wavelength modes. The effect of such non-Gaussian covariance can be modeled through additional freedom in the theoretical CMB angular power spectrum and can lead to different inferred values of the standard cosmological parameters relative to those in $\Lambda$CDM. Taking the collapsed limit of the primordial trispectrum in the quasi-single field inflation model as an example, we study how the six standard $\Lambda$CDM parameters shift when two additional parameters describing the trispectrum are allowed. The reduced statistical significance of the Hubble tension in the extended model allows us to combine the Planck temperature data and the type Ia supernovae data from Panstarrs with the distance-ladder measurement of the Hubble constant. This combination of data shows strong evidence for a primordial trispectrum-induced non-Gaussian covariance, with a likelihood improvement of $\Delta {\chi }^2\approx -15$ (with two additional parameters) relative to $\Lambda$CDM.

当原始波动为非高斯分布时，我们研究了CMB波动的角功率谱估计中的协方差。非高斯协方差来自于非零连接的四点相关函数（或傅立叶空间中的三光谱），当长波（超CMB）模式与短波模式强烈耦合时，非高斯协方差可能会很大。这种非高斯协方差的影响可以通过理论CMB角功率谱中的附加自由度来建模，并且可以导致相对于标准CMB而言，标准宇宙学参数的推断值不同。$\Lambda$CDM。以准单场通货膨胀模型中原始三光谱的坍塌极限为例，我们研究了六标准$\Lambda$当允许使用两个额外的描述三光谱的参数时，CDM参数会移动。哈勃张力在扩展模型中统计意义的降低使我们可以将普朗克温度数据和Panstarrs的Ia型超新星数据与哈勃常数的距离阶梯测量值结合起来。数据的组合为原始三光谱诱发的非高斯协方差提供了有力的证据，并可能改善$\Delta {\chi }^2\approx -15$ （具有两个附加参数）相对于 $\Lambda$CDM。