# w-M Phantom Transition at z_{t}<0.1 as a Resolution of the Hubble Tension

Published in *Physical Review D*, 2020

# Abstract

A rapid phantom transition of the dark energy equation of state parameter w at a transition redshift z_{t}<0.1 of the form w(z)=-1+Δw·Θ(z_{t}-z) with Δw<0 can lead to a higher value of the Hubble constant while closely mimicking a Planck18/ΛCDM form of the comoving distance for . Such a transition however would imply a significantly lower value of the SnIa absolute magnitude M than the value M_{C} imposed by local Cepheid calibrators at z<0.01. Thus, in order to resolve the H_{0} tension it would need to be accompanied by a similar transition in the value of the SnIa absolute magnitude M as M(z)=M_{C}+ΔM·Θ(z-z_{t}) with ΔM<0. This is a Late w-M phantom transition (LwMPT). It may be achieved by a sudden reduction of the value of the normalized effective Newton constant μ=G_{eff}/G_{N} by about 6% assuming that the absolute luminosity of SnIa is proportional to the Chandrasekhar mass which varies as μ^{-3/2}. We demonstrate that such an ultra low z abrupt feature of w-M provides a better fit to cosmological data compared to smooth late time deformations of H(z) that also address the Hubble tension. For z_{t}=0.02 we find Δw≃-4, ΔM≃-0.1. This model also addresses the growth tension due to the predicted lower value of μ at z>z_{t}. A prior of Δw=0 (no w transition) can still resolve the H_{0} tension with a larger amplitude M transition with ΔM≃-0.2 at z_{t}≃0.01. This implies a larger reduction of μ for z>0.01 (about 12%). The LwMPT can be generically induced by a scalar field non-minimally coupled to gravity with no need of a screening mechanism since in this model μ=1 at z<0.01.

# Cite

If you use any of the above codes or the figures in a published work please cite the following paper: *w-M Phantom Transition at z _{t}<0.1 as a Resolution of the Hubble Tension*

George Alestas, Lavrentios Kazantzidis and Leandros Perivolaropoulos

Phys.Rev.D 103 (2021) 8, 083517, arxiv:2012.13932.

Any further questions/comments are welcome.

# Authors Lists

George Alestas - g.alestas@uoi.gr

Lavrentios Kazantzidis - l.c.kazantzidis@gmail.com

Leandros Perivolaropoulos - leandros@uoi.gr