Accelerated cosmological expansion without tension in the Hubble parameter

TL;DR

This paper proposes explicit solutions for the Hubble parameter that reconcile the accelerated expansion of the universe with local measurements, addressing the Hubble tension and linking galaxy dynamics to cosmological evolution.

Contribution

It introduces new explicit solutions for H(z) that are consistent with local H0 measurements and explores the connection between galaxy dynamics and cosmological parameters.

Findings

The first solution is free of H0 tension with local surveys.

The second solution is disfavored at 2.7 sigma.

Galaxy dynamics constrain dark matter mass to less than 10^{-30} eV.

Abstract

The $H_0$-tension problem poses a confrontation of dark energy driving late-time cosmological expansion measured by the Hubble parameter $H(z)$ over an extended range of redshifts $z$. Distinct values $H_0\simeq 73$ km\,s$^{-1}$Mpc$^{-1}$ and $H_0\simeq 68$ km\,s$^{-1}$Mpc$^{-1}$ obtain from surveys of the Local Universe and, respectively, $\Lambda$CBM analysis of the CMB. These are representative of accelerated expansion with $H^\prime(0)\simeq0$ by $\Lambda=\omega_0^2$ and, respectively, $H^\prime(0)>0$ in $\Lambda$CDM, where $\omega_0=\sqrt{1-q}H$ is a fundamental frequency of the cosmological horizon in a Friedmann-Robertson-Walker universe with deceleration parameter $q(z)=-1+(1+z)H^{-1}H^\prime(z)$. Explicit solutions $H(z)=H_0\sqrt{1+\omega_m(6z+12z^2+12z^3+6z^4+(6/5)z^5)}$ and, respectively, $H(z)=H_0\sqrt{1-\omega_m+\omega_m(1+z)^3}$ are here compared with recent data on $H(z)$ over $0\lesssim z \lesssim2$. The first is found to be free of tension with $H_0$ from local surveys, while the latter is disfavored at $2.7\sigma$. A further confrontation obtains in galaxy dynamics by a finite sensitivity of inertia to background cosmology in weak gravity, putting an upper bound of $m\lesssim 10^{-30}$eV on the mass of dark matter. A $C^0$ onset to weak gravity at the de Sitter scale of acceleration $a_{dS}=cH(z)$, where $c$ denotes the velocity of light, can be seen in galaxy rotation curves covering $0\lesssim z \lesssim 2$. Weak gravity in galaxy dynamics hereby provides a proxy for cosmological evolution.