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arXiv · 2511.11929

Symmetric Bimetric Cosmology: A Minimal Extension of {\Lambda}CDM

Ghani Imadouchene
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Abstract

We construct and analyze a symmetric bimetric cosmological model connecting Anti-de Sitter (AdS) and de Sitter (dS) regimes through a coupled scalar field. Starting from a Lagrangian with Einstein-Hilbert terms for two FLRW metrics and an inter-metric potential, we derive modified Friedmann and Klein-Gordon equations governing their evolution. In the symmetric effective-fluid limit, the model reproduces the main phenomenology of the $\Lambda$CDM cosmology with a small dynamical correction proportional to $(1+z)^{-3}$, and naturally satisfies local-gravity constraints through Vainshtein screening. This article outlines the theoretical structure and calibration of the model within a dual-geometry cosmological setting.

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Ghani Imadouchene. 2025-11-14. Symmetric Bimetric Cosmology: A Minimal Extension of {\Lambda}CDM. https://arxiv.org/abs/2511.11929

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