Late-Transition Interacting Thawer Dark Energy: Model Definition and Benchmark Consistency Tests

Slava G. Turyshev; Diogo H. F. de Souza

doi:10.1103/1n9h-9yj7

paper

Late-Transition Interacting Thawer Dark Energy: Model Definition and Benchmark Consistency Tests

arXiv:2604.06261 · doi:10.1103/1n9h-9yj7

Abstract

We formulate the late-transition interacting thawer (LTIT) as a late-activating, variable-coupling realization of coupled quintessence in which a canonical scalar field couples conformally only to cold dark matter. The construction is a non-universal dark-sector interaction: baryons and radiation remain minimally coupled, while CDM follows a conformally related metric. This structure ties three observational sectors to one microscopic mechanism--the pre-recombination calibration scale, the low-redshift expansion history, and the coupled growth response. We derive the exact background equations, the exact CDM scaling identity $\rhoc(a)=ρ_{c0}a^{-3}C[ϕ(a)]/C(ϕ_0)$, and the coupled CDM--scalar perturbation equations in synchronous gauge in a form suitable for Einstein--Boltzmann solvers. In the representative benchmarks, $Ω_{ϕ} (z_{*}) \sim 1 0^{- 9}$ , $∣Δ r_{d} / r_{d} ∣ \leq 3.82 \times 1 0^{- 3}$ , and $max_{0 < z < 3} ∣ E / E_{Λ CDM} - 1∣ \leq 0.380%$ , while the quasi-static growth indicator ranges from $0.725%$ to $5.94%$ . LTIT therefore demonstrates how late activation can preserve the early calibration sector while producing a perturbation-sensitive signature, providing a concrete target for Boltzmann-level tests of interacting dark energy.

10 pages, 3 figures, 2 tables

Late-Transition Interacting Thawer Dark Energy: Model Definition and Benchmark Consistency Tests

Abstract

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