Cosmic viscosity as a remedy for tension between PLANCK and LSS data

Abstract

Measurements of ${\sigma }_8$ from large scale structure observations show a discordance with the extrapolated ${\sigma }_8$ from Planck CMB parameters using $\Lambda$CDM cosmology. Similar discordance is found in the value of $H_0$ and ${\Omega }_m$. In this paper, we show that the presence of viscosity in cold dark matter, shear or bulk or combination of both, can remove the above mentioned conflicts simultaneously. This indicates that the data from Planck CMB observation and different LSS observations prefer small but non-zero amount of viscosity in cold dark matter fluid.

16 pages, 13 figs, matches accepted version in JCAP

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Cited by in corpus (7)

• Cosmological discordances II: Hubble constant, Planck and large-scale-structure data sets
• Relaxing the ${\sigma }_8$-tension through running vacuum in the Universe
• Accelerated and decelerated expansion in a causal dissipative cosmology
• Can the Hubble tension be resolved by bulk viscosity?
• Linearized propagation equations for metric fluctuations in a general (non-vacuum) background geometry
• Global 21-cm brightness temperature in viscous dark energy models
• Scalar field unification of interacting viscous dark fluid from a geometrical scalar-tensor theory of gravity