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arXiv · 2610.41077

Vacuum Phase Transition and Decay to Cross the Phantom Divide

William Giarè·Kushal Lodha·Robert R. Caldwell·Eleonora Di Valentino·Eric V. Linder
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Abstract

We show that the vacuum metamorphosis model with decay fits current baryon acoustic oscillation and supernova distance data and cosmic microwave background measurements significantly better than $Λ$CDM and nearly as well as $w_0w_a$CDM with the same number of parameters. Vacuum metamorphosis with decay provides a physically motivated model of dark energy and an explanation of current cosmological data. In this scenario, non-perturbative quantum effects of a massive scalar field freeze the Ricci scalar curvature when it reaches a critical value proportional to the mass squared, inducing a phase transition in the scalar field, giving a phantom dark energy equation of state $w<-1$. After the phase transition, vacuum energy decays into light particles, providing a natural mechanism for the dark-energy equation of state to cross the phantom divide from $w<-1$ to $w>-1$, in agreement with current cosmological indications, without requiring an explicit coupling to matter.

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William Giarè, Kushal Lodha, Robert R. Caldwell, Eleonora Di Valentino, Eric V. Linder. 2026-10-29. Vacuum Phase Transition and Decay to Cross the Phantom Divide. https://arxiv.org/abs/2610.41077

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