%0 Generic %1 abitbol2019measuring %A Abitbol, Maximilian H. %A Hill, J. Colin %A Chluba, Jens %D 2019 %K tifr %T Measuring the Hubble constant from the cooling of the CMB monopole %U http://arxiv.org/abs/1910.09881 %X The cosmic microwave background (CMB) monopole temperature evolves with the inverse of the cosmological scale factor, independent of many cosmological assumptions. With sufficient sensitivity, real-time cosmological observations could thus be used to measure the local expansion rate of the Universe using the cooling of the CMB. We forecast how well a CMB spectrometer could determine the Hubble constant via this method. The primary challenge of such a mission lies in the separation of Galactic and extra-Galactic foreground signals from the CMB at extremely high precision. However, overcoming these obstacles could potentially provide an independent, highly robust method to shed light on the current low-/high-$z$ Hubble tension. We find that a 3\% measurement of the Hubble constant requires an effective sensitivity to the CMB monopole temperature of approximately $60~pK \sqrtyr$ throughout a 10-year mission. This sensitivity would also enable high-precision measurements of the expected $Łambda$CDM spectral distortions, but remains futuristic at this stage.

@misc{abitbol2019measuring, abstract = {The cosmic microwave background (CMB) monopole temperature evolves with the inverse of the cosmological scale factor, independent of many cosmological assumptions. With sufficient sensitivity, real-time cosmological observations could thus be used to measure the local expansion rate of the Universe using the cooling of the CMB. We forecast how well a CMB spectrometer could determine the Hubble constant via this method. The primary challenge of such a mission lies in the separation of Galactic and extra-Galactic foreground signals from the CMB at extremely high precision. However, overcoming these obstacles could potentially provide an independent, highly robust method to shed light on the current low-/high-$z$ Hubble tension. We find that a 3\% measurement of the Hubble constant requires an effective sensitivity to the CMB monopole temperature of approximately $60~\mathrm{pK \sqrt{yr}}$ throughout a 10-year mission. This sensitivity would also enable high-precision measurements of the expected $\Lambda$CDM spectral distortions, but remains futuristic at this stage.}, added-at = {2019-10-23T07:24:38.000+0200}, author = {Abitbol, Maximilian H. and Hill, J. Colin and Chluba, Jens}, biburl = {https://www.bibsonomy.org/bibtex/2176b0bace63f1cb5838fd392ae4f146a/citekhatri}, description = {Measuring the Hubble constant from the cooling of the CMB monopole}, interhash = {a09eb214b6c1be9a0210151ec898067a}, intrahash = {176b0bace63f1cb5838fd392ae4f146a}, keywords = {tifr}, note = {cite arxiv:1910.09881}, timestamp = {2019-10-23T07:24:38.000+0200}, title = {Measuring the Hubble constant from the cooling of the CMB monopole}, url = {http://arxiv.org/abs/1910.09881}, year = 2019 }