Gravity emerging from internal symmetry of quantum fields*

The standard model of particle physics describes three of the four known fundamental forces of nature - electromagnetic, weak, and strong interactions. The fourth interaction, gravity, has been challenging to unify with the standard model since the underlying theories are largely incompatible. Quantum field theory is based on special unitary symmetries associated with internal vector spaces of quantum fields. The special-unitary-symmetry-based approach to the description of gravity has remained unknown. Here we reveal a profound connection between the stress-energy-momentum tensor and the special unitary symmetry. This enables the development of the Yang-Mills gauge theory of unified gravity [arXiv:2310.01460]. The spinorial electrodynamics based on our approach is also studied [arXiv:2310.02285]. We show that, in the classical regime for weak gauge coupling, unified gravity is equivalent to the so-called teleparallel equivalent of general relativity. Beyond-general-relativity investigations are enabled in the case of finite gauge coupling. Unified gravity can provide a new tool for the examination of strong gravitational fields encountered in black holes and at the possible beginning of time.