Metastable Dark Energy on the Phantom Brane
Abstract
Recent DESI observations hint at a preference for dynamical dark energy with an equation of state (EoS) that crosses the phantom divide at w=−1. In this work, we investigate \textit{metastable} dark energy (DE) on the minimal phantom brane. Braneworld effects lead to w < −1 at early times, whereas metastable decay of DE results in w > −1 at late times. We consider three metastable decay prescriptions on the phantom brane: an exponentially decaying DE component (M1), decay of DE into non-baryonic dark matter (M2), and decay into dark radiation (M3). Using CMB observations, DESI DR2 BAO measurements, and the DES-Dovekie Type Ia supernova sample, we compare these models with ΛCDM, the Chevallier--Polarski--Linder (CPL) parametrization, and the minimal phantom-brane model with a non-decaying Λ. We find that metastable models on the brane are preferred over ΛCDM, their decay rates being Γ/H0=0.362±0.086, 0.539±0.125, and 0.483±0.112 for M1, M2, and M3, respectively. Best fits of metastable models improve over ΛCDM by Δχ2MAP=−17.14, −18.76, and −18.22, while the corresponding ΔDIC values are −8.66, −9.63, and −6.56. Braneworld screening drives effective phantom behaviour at z≳0.4, while DE decay drives the EoS toward non-phantom values closer to the present epoch, with the phantom divide w=−1 being crossed at z ≃ 0.3--$0.4$. These results show that the interplay between metastable decay and phantom-brane screening provides a simple physical mechanism for an effective crossing of the phantom divide consistent with DESI observations.
Related
- Distinguishing Coupled Dark Matter Dark Energy from Kinematic Phantom Crossing
- Observational constraints on scalar-vector-tensor dark energy with phantom-divide crossing
- Phantom-Divide Crossing in Barrow-Tsallis Holographic Dark Energy with a Scale-Dependent Barrow Exponent
- Metastable Neutron Stars as Transient-Rate Detectors of Heavy Dark Matter
- Beyond w0−wa and Phantom Crossing: Testing Models of Coupled Dark Sector
BibTeX
@misc{mukherjee2026metastable,
title = {{Metastable Dark Energy on the Phantom Brane}},
author = {Purba Mukherjee and Arman Shafieloo and Varun Sahni and Yuri Shtanov},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.39039},
eprint = {2609.39039},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.39039},
}
RIS
TY - UNPB
TI - Metastable Dark Energy on the Phantom Brane
AU - Purba Mukherjee
AU - Arman Shafieloo
AU - Varun Sahni
AU - Yuri Shtanov
PY - 2026
DA - 2026/09/30
PB - arXiv
DO - 10.48550/arxiv.2609.39039
UR - https://arxiv.org/abs/2609.39039
AB - Recent DESI observations hint at a preference for dynamical dark energy with an equation of state (EoS) that crosses the phantom divide at w=−1. In this work, we investigate \textit{metastable} dark energy (DE) on the minimal phantom brane. Braneworld effects lead to w < −1 at early times, whereas metastable decay of DE results in w > −1 at late times. We consider three metastable decay prescriptions on the phantom brane: an exponentially decaying DE component (M1), decay of DE into non-baryonic dark matter (M2), and decay into dark radiation (M3). Using CMB observations, DESI DR2 BAO measurements, and the DES-Dovekie Type Ia supernova sample, we compare these models with ΛCDM, the Chevallier--Polarski--Linder (CPL) parametrization, and the minimal phantom-brane model with a non-decaying Λ. We find that metastable models on the brane are preferred over ΛCDM, their decay rates being Γ/H_0=0.362±0.086, 0.539±0.125, and 0.483±0.112 for M1, M2, and M3, respectively. Best fits of metastable models improve over ΛCDM by Δχ^2_MAP=−17.14, −18.76, and −18.22, while the corresponding ΔDIC values are −8.66, −9.63, and −6.56. Braneworld screening drives effective phantom behaviour at z≳0.4, while DE decay drives the EoS toward non-phantom values closer to the present epoch, with the phantom divide w=−1 being crossed at z ≃ 0.3--$0.4$. These results show that the interplay between metastable decay and phantom-brane screening provides a simple physical mechanism for an effective crossing of the phantom divide consistent with DESI observations.
ER -