A new relativistic theory for Modified Newtonian Dynamics

TL;DR

This paper introduces a new relativistic gravitational theory that explains galactic dynamics and cosmological observations, ensuring stability and compatibility with known phenomena.

Contribution

It presents a novel relativistic framework for Modified Newtonian Dynamics that aligns with cosmological data and is free of ghost instabilities.

Findings

Agreement with cosmic microwave background observations

Compatibility with matter power spectra

Second-order action free of ghost instabilities

Abstract

We propose a relativistic gravitational theory leading to modified Newtonian dynamics, a paradigm that explains the observed universal galactic acceleration scale and related phenomenology. We discuss phenomenological requirements leading to its construction and demonstrate its agreement with the observed cosmic microwave background and matter power spectra on linear cosmological scales. We show that its action expanded to second order is free of ghost instabilities and discuss its possible embedding in a more fundamental theory.