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arXiv · 2504.02541

$\Lambda$CDM from broken diffeomorphisms

Javier de Cruz Pérez·Antonio L. Maroto
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Abstract

We present a simple field theory model with reduced invariance under diffeomorphisms whose energy-momentum tensor is identical to the sum of pressureless irrotational matter and a cosmological constant. The model action is built from a single scalar field with a canonical kinetic term without any potential or Lagrange multiplier terms. The coupling to gravity is realized through a particular transverse diffeomorphism invariant volume element. The corresponding sound speed is exactly zero in any background geometry and the model is dynamically identical to $\Lambda$CDM. By restoring the full diffeomorphism invariance through the introduction of Stueckelberg-like fields, we obtain an equivalent local scalar-vector theory.

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Javier de Cruz Pérez, Antonio L. Maroto. 2025-04-03. $\Lambda$CDM from broken diffeomorphisms. https://doi.org/10.1103/rxnw-gvyd

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