Interacting Dark Energy Models in Cosmology

Interacting dark energy models posit a dynamic energy exchange between dark energy and dark matter beyond gravitational coupling. These frameworks extend the standard Lambda Cold Dark Matter model by introducing a coupling function that governs the transfer of energy–momentum in the dark sector. Such couplings can be constant or evolve with cosmic time, leading to modified expansion histories and growth of structure. A key motivation lies in addressing persistent cosmological tensions, notably the discrepancy between early- and late-time measurements of the Hubble constant and the amplitude of matter clustering. By allowing dark energy to decay into dark matter, or vice versa, these models can shift the matter density parameter and clustering metrics, offering potential alleviation of observational anomalies. The phenomenology spans a wide array of interaction kernels—including proportionality to energy densities or the Hubble rate—and predicts distinctive signatures in cosmic microwave background anisotropies, baryon acoustic oscillations, supernova luminosity distances and weak lensing surveys. Future wide-field surveys and precision cosmology missions are poised to test the viability of interacting scenarios through refined measurements of cosmic expansion and structure growth.

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Interacting Dark Energy Models in Cosmology publication trend

The graph below shows the total number of articles in interacting dark energy models in cosmology across all publications each year (not limited to Nature Index journals).

Technical terms

Dark energy: A form of energy causing the accelerated expansion of the Universe, modelled as a fluid with negative pressure.

Dark matter: A non-luminous component of matter that interacts gravitationally to form cosmic structures.

Coupling parameter: A dimensionless factor characterising the strength and direction of energy exchange between dark energy and dark matter.

Baryon acoustic oscillations: Regular fluctuations in the density of visible baryonic matter used as a standard cosmological ruler.

Equation of state: The relation between pressure and energy density of a cosmological fluid, often denoted w for dark energy.

Cosmic microwave background: Relic radiation from the early Universe that encodes signatures of its composition and expansion history.

Hubble constant (H0): The present-day rate of cosmic expansion, typically measured in km s−1 Mpc−1.

References

1. On the dynamics of a dark sector coupling. Journal of High Energy Astrophysics (2023).
2. Dark sector interaction: a remedy of the tensions between CMB and LSS data. European Physical Journal C (2019).
3. Model-independent reconstruction of the interacting dark energy kernel: Binned and Gaussian process. Journal of Cosmology and Astroparticle Physics (2023).
4. Interacting Dark Energy after DESI Baryon Acoustic Oscillation Measurements. Physical Review Letters (2024).
5. Constraints on Interacting Dark Energy Models from the DESI Baryon Acoustic Oscillation and DES Supernovae Data. The Astrophysical Journal (2024).