A $w$ phantom transition at $z_t<0.1$ as a resolution of the Hubble tension. (arXiv:2012.13932v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Alestas_G/0/1/0/all/0/1">George Alestas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kazantzidis_L/0/1/0/all/0/1">Lavrentios Kazantzidis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perivolaropoulos_L/0/1/0/all/0/1">Leandros Perivolaropoulos</a>

A rapid transition of the dark energy equation of state parameter $w$ at a
transition redshift $z_t<0.1$ from $wsimeq -1$ at $z>z_t$ to $w<-1$ at $z<z_t$
can lead to a higher value of the Hubble constant while closely mimicking a
Planck18/$Lambda$CDM form of the comoving distance
$r(z)=int_0^zfrac{dz’}{H(z’)}$ for $z>z_t$. Such a Late $w$ Phantom
Transition ($LwPT$) avoids the discontinuity of $H(z)$ suggested in previous
studies and thus does not require a step in the Pantheon Hubble diagram which
is strongly constrained. We demonstrate that such an ultra low $z$ abrupt
feature of $w(z)$ provides a better fit to cosmological data compared to smooth
late time deformations of $H(z)$ that also address the Hubble tension. The
strongly present day phantom dark energy behavior implied by this class of
models hints towards a rapid approach of a Big Rip singularity which for
$z_t=0.02$ will rip the universe in less than 3.5 billion years. Early hints of
such effect may be observable in the dynamics of the nearest and largest bound
systems (e.g. Virgo structures). The $LwPT$ can be generically induced by a
phantom scalar field frozen by Hubble friction mimicking the cosmological
constant and currently entering its ghost instability phase as Hubble friction
decreases below the field dynamical scale.

A rapid transition of the dark energy equation of state parameter $w$ at a
transition redshift $z_t<0.1$ from $wsimeq -1$ at $z>z_t$ to $w<-1$ at $z<z_t$
can lead to a higher value of the Hubble constant while closely mimicking a
Planck18/$Lambda$CDM form of the comoving distance
$r(z)=int_0^zfrac{dz’}{H(z’)}$ for $z>z_t$. Such a Late $w$ Phantom
Transition ($LwPT$) avoids the discontinuity of $H(z)$ suggested in previous
studies and thus does not require a step in the Pantheon Hubble diagram which
is strongly constrained. We demonstrate that such an ultra low $z$ abrupt
feature of $w(z)$ provides a better fit to cosmological data compared to smooth
late time deformations of $H(z)$ that also address the Hubble tension. The
strongly present day phantom dark energy behavior implied by this class of
models hints towards a rapid approach of a Big Rip singularity which for
$z_t=0.02$ will rip the universe in less than 3.5 billion years. Early hints of
such effect may be observable in the dynamics of the nearest and largest bound
systems (e.g. Virgo structures). The $LwPT$ can be generically induced by a
phantom scalar field frozen by Hubble friction mimicking the cosmological
constant and currently entering its ghost instability phase as Hubble friction
decreases below the field dynamical scale.

http://arxiv.org/icons/sfx.gif