Is a non-vanishing cosmological constant really needed?

TL;DR

This paper demonstrates that the observed accelerated expansion of the universe can be explained without a cosmological constant by using open Friedmann-Lemaitre solutions with a time-dependent Hubble parameter and a global flatness condition.

Contribution

It shows that an open universe with zero cosmological constant can account for observed acceleration and flatness, challenging the necessity of dark energy.

Findings

Observed Hubble parameter matches predictions without 

Global flatness condition holds at all times

No cosmological constant needed for acceleration

Abstract

Using consistenly the compact Friedmann-Lemaitre solutions for an open $(k=-0.580)$ universe with zero cosmological constant ($\Lambda = 0$) we show that the oberved apparent accelerated expansion is compatible with a time dependent Hubble parameter $H=\dot{R}/R$ equal to $H=87.95$ km/s/Mpc at $t=10.39$ Gys, $H_{0}=67.9 \pm 4 $ km/s/Mpc at $t_{o}=13.7 \pm 0.2$ Gyrs (present), $H=61.4$ km/s/Mpc at $t=15$ Gyrs and with an apparent global flatness given by $1=\Omega_{m}+\Omega_{r}+\Omega_{k}$ at all times which, properly averaged from galaxy formation times to present, gives $<\Omega_{m}>=0.272$, $<\Omega_{r}>=0.005$, $<\Omega_{k}>=0.728$. Therefore, no cosmological constant is needed.