# Misalignment & Co.: (Pseudo-)scalar and vector dark matter with curvature couplings

## TL;DR

This paper investigates how non-minimal curvature couplings of light scalar and vector fields influence their evolution as dark matter, affecting relic density and density fluctuations, and relaxing isocurvature constraints.

## Contribution

It introduces the impact of curvature couplings on the cosmological evolution of scalar and vector dark matter, revealing new viable parameter space regions.

## Key findings

- Curvature couplings significantly alter superhorizon evolution.
- Relic density predictions are affected by non-minimal couplings.
- Isocurvature constraints are weakened, expanding viable models.

## Abstract

Motivated by their potential role as dark matter, we study the cosmological evolution of light scalar and vector fields non-minimally coupled to gravity. Our focus is on a situation where the dominant contribution to the energy density arises from the misalignment mechanism. In addition, we also discuss the possibility that dark matter is generated in a stochastic scenario or from inflationary fluctuations. Even small deviations in the non-minimal couplings from the standard scenarios lead to significant qualitative and quantitative changes. This is due to the curvature-coupling driven superhorizon evolution of the homogeneous field and the non-zero momentum modes during inflation. Both the relic density yield and the large-scale density fluctuations are affected. For the misalignment mechanism, this results in a weakening of the isocurvature constraints and opens up new viable regions of parameter space.