Forecasting Coupled Dark Energy Parameters with the One-Loop Galaxy Power Spectrum
Abstract
We forecast constraints on the parameters of the coupled dark energy model using DESI and Euclid data with the one-loop galaxy power spectrum. We investigate the distinguishability of our model from the zero-coupling scenario at the 1σ level and explore how the parameter constraints depend on the fiducial coupling βfid, the fixed potential slope parameter ν, the maximum wavenumber kmax, and different prior choices. We find that the inclusion of mildly non-linear scales improves the constraints on the coupling by roughly a factor of five. Then, we address the question of which is the minimum value of β that can be distinguished from zero at 1σ. We find that for our reference case kmax=0.2 h/Mpc, β=0.15 lies roughly 1σ above zero. In the most optimistic case with kmax=0.3 h/Mpc and including a Planck prior on Ωm0, this value can be reduced to $0.05$. These values are substantially larger than the current constraints on β, but the latter have been obtained assuming β to be constant from at least the decoupling epoch to today, while we only employ late-time data. We conclude therefore that only models that allow for time-varying couplings can be detected with late-time datasets.
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BibTeX
@misc{tudes2026forecasting,
title = {{Forecasting Coupled Dark Energy Parameters with the One-Loop Galaxy Power Spectrum}},
author = {Bilal Tüdes and Luca Amendola},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14966},
eprint = {2609.14966},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14966},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Forecasting Coupled Dark Energy Parameters with the One-Loop Galaxy Power Spectrum
AU - Bilal Tüdes
AU - Luca Amendola
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.14966
UR - https://arxiv.org/abs/2609.14966
AB - We forecast constraints on the parameters of the coupled dark energy model using DESI and Euclid data with the one-loop galaxy power spectrum. We investigate the distinguishability of our model from the zero-coupling scenario at the 1σ level and explore how the parameter constraints depend on the fiducial coupling β_fid, the fixed potential slope parameter ν, the maximum wavenumber k_max, and different prior choices. We find that the inclusion of mildly non-linear scales improves the constraints on the coupling by roughly a factor of five. Then, we address the question of which is the minimum value of β that can be distinguished from zero at 1σ. We find that for our reference case k_max=0.2 h/Mpc, β=0.15 lies roughly 1σ above zero. In the most optimistic case with k_max=0.3 h/Mpc and including a Planck prior on Ω_m0, this value can be reduced to $0.05$. These values are substantially larger than the current constraints on β, but the latter have been obtained assuming β to be constant from at least the decoupling epoch to today, while we only employ late-time data. We conclude therefore that only models that allow for time-varying couplings can be detected with late-time datasets.
ER -