The Spin Tensor of Dark Matter and the Hubble Parameter Tension

Abstract

Allowing for a nonvanishing spin tensor for cold dark matter (${\omega }_{\mathrm{DM}}=0$) has the consequence of giving rise to an effective $\mathrm{FLRW}$ dynamics with a small negative barotropic constant for an effective dark matter density ($-1/3<{\omega }_{\mathrm{eff}}\le 0$). This turns out to solve the Hubble parameter tension in a straightforward way.

6 pages, no figures. Minor corrections, references added