Structural Analysis of a Scalar-Tensor Realization of Interacting Dark Energy

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Hauptverfasser: MV, Pradosh Keshav, Kavya, NS, Arun, Kenath
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Veröffentlicht: 2026
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author MV, Pradosh Keshav
Kavya, NS
Arun, Kenath
author_facet MV, Pradosh Keshav
Kavya, NS
Arun, Kenath
contents We investigate a class of interacting dark energy (IDE) models arising from density-driven spontaneous symmetry breaking in a conformally coupled scalar-tensor framework. In this construction, the dark matter-scalar interaction is dynamically activated as the cosmological density evolves, and the redshift dependence of the coupling follows a logistic profile whose steepness is determined by the local curvature of the symmetry-breaking potential. Working in the controlled adiabatic tracking regime, we implement the resulting epoch-dependent interaction in a perturbative background close to $Λ$CDM and confront the model with late-time cosmological data, including Planck 2018 CMB lensing reconstruction, redshift-space distortions, and Pantheon+SH0ES supernova data. We analyze realizations in which the activation index is allowed to vary and compare them with a restricted realization in which it is fixed to the canonical quadratic minimum value, thereby probing the structural role of the activation profile. We find no statistically significant preference for interaction over $Λ$CDM; current observations constrain the model to a hierarchical regime in which the scalar remains heavier than the Hubble scale at activation and background deformations remain perturbatively small. Allowing the activation index to vary preserves an extended degeneracy direction in parameter space, whereas fixing it removes this freedom and leads to a contraction of the allowed posterior region once geometric and growth data are combined. Our results delineate the viable parameter regime of symmetry-breaking IDE and clarify the structural distinction between microphysically motivated scalar-tensor realizations and phenomenological interacting models.
format Preprint
id arxiv_https___arxiv_org_abs_2603_25595
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Structural Analysis of a Scalar-Tensor Realization of Interacting Dark Energy
MV, Pradosh Keshav
Kavya, NS
Arun, Kenath
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
We investigate a class of interacting dark energy (IDE) models arising from density-driven spontaneous symmetry breaking in a conformally coupled scalar-tensor framework. In this construction, the dark matter-scalar interaction is dynamically activated as the cosmological density evolves, and the redshift dependence of the coupling follows a logistic profile whose steepness is determined by the local curvature of the symmetry-breaking potential. Working in the controlled adiabatic tracking regime, we implement the resulting epoch-dependent interaction in a perturbative background close to $Λ$CDM and confront the model with late-time cosmological data, including Planck 2018 CMB lensing reconstruction, redshift-space distortions, and Pantheon+SH0ES supernova data. We analyze realizations in which the activation index is allowed to vary and compare them with a restricted realization in which it is fixed to the canonical quadratic minimum value, thereby probing the structural role of the activation profile. We find no statistically significant preference for interaction over $Λ$CDM; current observations constrain the model to a hierarchical regime in which the scalar remains heavier than the Hubble scale at activation and background deformations remain perturbatively small. Allowing the activation index to vary preserves an extended degeneracy direction in parameter space, whereas fixing it removes this freedom and leads to a contraction of the allowed posterior region once geometric and growth data are combined. Our results delineate the viable parameter regime of symmetry-breaking IDE and clarify the structural distinction between microphysically motivated scalar-tensor realizations and phenomenological interacting models.
title Structural Analysis of a Scalar-Tensor Realization of Interacting Dark Energy
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2603.25595