Investigating the coincidence problem with Interacting Dark Energy Models
Abstract
Interacting dark energy (IDE) models within the framework of general relativity (GR) provide a possible extension of the standard ΛCDM model and may alleviate the coincidence problem. In this paper, we investigate three phenomenological interacting dark energy models using a combination of cosmic chronometer H(z) measurements and two standard cosmic rulers: baryon acoustic oscillations (BAO) and quasars (QSO). The observational constraints indicate a mild preference for energy transfer from dark energy to dark matter, a scenario that may help alleviate the cosmic coincidence problem. However, the standard ΛCDM model, corresponding to the absence of interaction, remains fully consistent with the observational data, as the no-interaction case lies within the 1σ confidence interval of the inferred interaction parameter for all three IDE models. Model comparison, using Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC), further indicates that the current data do not provide statistically significant evidence favouring any IDE model over the standard ΛCDM scenario or over one another. These results suggest that, while a weak dark-sector interaction is permitted by the data, present observations do not provide compelling evidence for departures from the standard ΛCDM model.
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BibTeX
@misc{singh2026investigating,
title = {{Investigating the coincidence problem with Interacting Dark Energy Models}},
author = {Kshitiz Singh and Savita Gahlaut},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.04234},
eprint = {2609.04234},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.04234},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Investigating the coincidence problem with Interacting Dark Energy Models
AU - Kshitiz Singh
AU - Savita Gahlaut
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.04234
UR - https://arxiv.org/abs/2609.04234
AB - Interacting dark energy (IDE) models within the framework of general relativity (GR) provide a possible extension of the standard ΛCDM model and may alleviate the coincidence problem. In this paper, we investigate three phenomenological interacting dark energy models using a combination of cosmic chronometer H(z) measurements and two standard cosmic rulers: baryon acoustic oscillations (BAO) and quasars (QSO). The observational constraints indicate a mild preference for energy transfer from dark energy to dark matter, a scenario that may help alleviate the cosmic coincidence problem. However, the standard ΛCDM model, corresponding to the absence of interaction, remains fully consistent with the observational data, as the no-interaction case lies within the 1σ confidence interval of the inferred interaction parameter for all three IDE models. Model comparison, using Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC), further indicates that the current data do not provide statistically significant evidence favouring any IDE model over the standard ΛCDM scenario or over one another. These results suggest that, while a weak dark-sector interaction is permitted by the data, present observations do not provide compelling evidence for departures from the standard ΛCDM model.
ER -