Constraining Violations of the Weak Equivalence Principle in the Dark Sector

TL;DR

This paper extends the effective field theory of dark energy to include dark matter modeled as a complex scalar field, analyzing how interactions may violate the weak equivalence principle and constraining these violations using cosmological data.

Contribution

It introduces a generalized framework for dark energy and dark matter interactions, specifically modeling dark matter with a complex scalar field and assessing equivalence principle violations.

Findings

Interactions in the dark matter sector can violate the weak equivalence principle.

Cosmological analyses place constraints on the degree of possible violations.

The model resembles ultralight axion scenarios.

Abstract

The effective field theory of dark energy is generalized to incorporate dark matter, which is modelled using a complex scalar field with a global $U(1)$ symmetry. The dark matter model used here has similarities to models of ultralight axion. Generic interaction terms in the dark matter sector violate the weak equivalence principle. The degree to which such violations can occur is constrained using a number of recent analyses and forecasts in cosmology.