Quantum Field Theory of Interacting Dark Matter/Dark Energy: Dark Monodromies

TL;DR

This paper addresses how to formulate a quantum-field-theory description of interacting dark matter and dark energy, showing that conventional heavy-DM/DE couplings are radiatively unstable and violate constraints on DE potentials and long-range forces. It then proposes a radiatively stable alternative based on ultralight axions arranged in a multi-axion monodromy framework, enabling significant DM/DE mixing while preserving EFT control. The authors develop and analyze a three-axion model, including both decoupled and mixed regimes, and explore cosmological evolution at the background and perturbation levels. They find that the coupled scenario can yield observable signatures—such as oscillations in the equation of state and small deviations in H(z) and d_A(z), plus potential domain-wall effects—while remaining within current cosmological bounds and offering clear targets for future observations. Overall, the work provides a UV-consistent pathway to testable DM/DE interactions through axion monodromies and stakes out concrete, testable cosmological predictions.

Abstract

We discuss how to formulate a quantum field theory of dark energy interacting with dark matter. We show that the proposals based on the assumption that dark matter is made up of heavy particles with masses which are very sensitive to the value of dark energy are strongly constrained. Quintessence-generated long range forces and radiative stability of the quintessence potential require that such dark matter and dark energy are completely decoupled. However, if dark energy and a fraction of dark matter are very light axions, they can have significant mixings which are radiatively stable and perfectly consistent with quantum field theory. Such models can naturally occur in multi-axion realizations of monodromies. The mixings yield interesting signatures which are observable and are within current cosmological limits but could be constrained further by future observations.

Figures (9)

• Figure 1: Dark matter scattering mediated by dark energy exchange.
• Figure 2: Dark energy self-energy from dark matter exchange.
• Figure 3: DM/DE coupling versus DM mass; shaded area below the hyperbola is allowed. Here DE is an ultralight quintessence field with a sub-Hubble mass.
• Figure 4: Hubble parameter and angular diameter distance compared to the Planck $\Lambda CDM$ value, for the coupled ($H$, $d_A$) and decoupled ($H_{\rm dec}$, $d_A^{\rm dec.}$) models.
• Figure 5: The total equation of state and the equation of state of the two light axions, compared to the $\Lambda$CDM case, for both coupled and decoupled models.