https://doi.org/10.1140/epjp/s13360-025-06237-9
Regular Article
Interacting dark sector with quadratic coupling: theoretical and observational viability
1
Departamento de Física, Universidade Federal de Sergipe, 49107-230, São Cristóvão, SE, Brazil
2
Instituto de Física, Universidade Federal da Bahia, 40170-155, Salvador, BA, Brazil
3
PPGCosmo, Universidade Federal do Espírito Santo, 29075-910, Vitória, ES, Brazil
Received:
26
February
2025
Accepted:
16
March
2025
Published online:
11
April
2025
Models proposing a nongravitational interaction between dark energy (DE) and dark matter (CDM) have been extensively studied as alternatives to the standard cosmological model. A common approach to describing the DE-CDM coupling assumes it to be linearly proportional to the dark energy density. In this work, we consider the model with interaction term 
. We show that for positive values of 
this model predicts a future violation of the Weak Energy Condition (WEC) for the dark matter component, and for a specific range of negative values of the CDM energy density can be negative in the past. We perform a parameter selection analysis for this model using data from Type Ia supernovae from the Pantheon sample, H(z) measurements from the Cosmic Chronometers sample, Baryon Acoustic Oscillations from the DESI survey, and Cosmic Microwave Background data from the Planck combined with the Hubble constant 
prior. Imposing a prior to ensure that the WEC is not violated, our model is consistent with 
CDM in 2
C.L., yet exhibits a preference for smaller values of 
, alleviating the tension between the CMB results from Planck 2018 and the weak gravitational lensing observations from the KiDS-1000 cosmic shear survey.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
