%0 Journal Article %1 adhikari2019supercmb %A Adhikari, Saroj %A Huterer, Dragan %D 2019 %K H0tension %T Super-CMB fluctuations can resolve the Hubble tension %U http://arxiv.org/abs/1905.02278 %X 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 $Łambda$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 $Łambda$CDM parameters shift when two additional parameters describing the trispectrum are allowed. We find that the combination of Planck temperature data along with type Ia supernovae from Panstarrs and the distance-ladder measurement of the Hubble constant shows strong evidence for a primordial trispectrum-induced non-Gaussian covariance, with a likelihood improvement of $\Delta \chi^2 -15$ relative to $Łambda$CDM. The improvement is driven by Planck data's preference for a higher lensing amplitude, which leads to an upward shift of the Planck-inferred Hubble constant.

@article{adhikari2019supercmb, abstract = {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. We find that the combination of Planck temperature data along with type Ia supernovae from Panstarrs and the distance-ladder measurement of the Hubble constant shows strong evidence for a primordial trispectrum-induced non-Gaussian covariance, with a likelihood improvement of $\Delta \chi^2 \approx -15$ relative to $\Lambda$CDM. The improvement is driven by Planck data's preference for a higher lensing amplitude, which leads to an upward shift of the Planck-inferred Hubble constant.}, added-at = {2019-05-08T10:41:26.000+0200}, author = {Adhikari, Saroj and Huterer, Dragan}, biburl = {https://www.bibsonomy.org/bibtex/212c2fbba567af35cf2297b9dcb2683c6/aseem.p}, description = {Super-CMB fluctuations can resolve the Hubble tension}, interhash = {4afcac37d0e5c06dc4501629690cda7f}, intrahash = {12c2fbba567af35cf2297b9dcb2683c6}, keywords = {H0tension}, note = {cite arxiv:1905.02278Comment: 5 pages, 2 figures}, timestamp = {2019-05-08T10:41:41.000+0200}, title = {Super-CMB fluctuations can resolve the Hubble tension}, url = {http://arxiv.org/abs/1905.02278}, year = 2019 }