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 ($-1/3<\omega_{\mathrm{eff}}\leq0$). This turns out to solve the Hubble parameter tension in a straightforward way.