Effective Fluid Description of the Dark Universe

Understand

We propose an effective anisotropic fluid description for a generic infrared-modified theory of gravity.

• In our framework, the additional component of the acceleration, commonly attributed to dark matter, is explained as a radial pressure generated by the reaction of the dark energy fluid to the presence of baryonic matter.
• Using quite general assumptions, and a microscopic description of the fluid in terms of a Bose-Einstein condensate of gravitons, we find the static, spherically symmetric solution for the metric in terms of the Misner-Sharp mass function and the fluid pressure.
• At galactic scales, we correctly reproduce the leading MOND-like $\log(r)$ and subleading $(1/r)\,\log(r)$ terms in the weak-field expansion of the potential.