@article{be767879eb7d4e758242d79d53c8aec6,
title = "Sigma-8 tension is a drag",
abstract = "Measurements of weak gravitational lensing at low redshifts (z≲0.5-1), quantified by the parameter S8, favor weaker matter clustering than that expected from the standard Λ cold dark matter (ΛCDM) cosmological model with the parameters determined by cosmic microwave background (CMB) measurements. However, the amplitude of matter clustering at higher redshifts, as probed by lensing of the CMB, is consistent with ΛCDM. In the literature, it has been found that the tension can be resolved by introducing a friction between dark matter and dark energy without altering the tightly constrained expansion history. Here, we show that in order to get a low S8 value consistent with the findings of cosmic shear under ΛCDM, cosmological measurements favor (at ∼3σ, in this one parameter model) a nonzero drag leading to a suppression of low-redshift power right precisely around the transition from matter to dark-energy domination. Our results hint at a connection between the S8 tension and the long-standing {"}cosmic coincidence problem.{"}We suggest ways to further probe the scenario.",
author = "Vivian Poulin and Bernal, {Jos{\'e} Luis} and Kovetz, {Ely D.} and Marc Kamionkowski",
note = "Funding Information: We thank Marco Baldi, Dario Bettoni, David Figueruelo, Jose Beltran Jimenez, Antony Lewis, Matteo Lucca, Florencia A. Teppa Pannia, and Sunny Vagnozzi for useful comments on the manuscript. The authors acknowledge the use of computational resources from the Excellence Initiative of Aix-Marseille University (A*MIDEX) of the “Investissements d{\textquoteright}Avenir” program. This project has received support from the European Union{\textquoteright}s Horizon 2020 research and innovation program under the Marie Skodowska-Curie Grant Agreement No. 860881-HIDDeN. This work has been partly supported by the CNRS-IN2P3 Grant Dark21. This project has received funding from the European Research Council (ERC) under the European Union{\textquoteright}s HORIZON-ERC-2022 (Grant Agreement No. 101076865). J. L. B. was supported by the Allan C. and Dorothy H. Davis Fellowship. E. D. K. was supported by a faculty fellowship from the Azrieli Foundation. M. K. was supported by NSF Grant No. 2112699 and the Simons Foundation. Publisher Copyright: {\textcopyright} 2023 American Physical Society.",
year = "2023",
month = jun,
day = "15",
doi = "10.1103/PhysRevD.107.123538",
language = "English",
volume = "107",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society",
number = "12",
}