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arXiv · 1711.11500

Rastall gravity is equivalent to Einstein gravity

Matt Visser
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Abstract

Rastall gravity, originally developed in 1972, is currently undergoing a significant surge in popularity. Rastall gravity purports to be a modified theory of gravity, with a non-conserved stress-energy tensor, and an unusual non-minimal coupling between matter and geometry, the Rastall stress-energy satisfying nabla_b [T_R]^{ab} = {λ/4} g^{ab} nabla_b R. Unfortunately, a deeper look shows that Rastall gravity is completely equivalent to Einstein gravity --- usual general relativity. The gravity sector is completely standard, based as usual on the Einstein tensor, while in the matter sector Rastall's stress-energy tensor corresponds to an artificially isolated part of the physical conserved stress-energy.

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Matt Visser. 2018-05-29. Rastall gravity is equivalent to Einstein gravity. https://doi.org/10.1016/j.physletb.2018.05.028

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