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