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arXiv · 1907.04625

The trace of the trace of the energy-momentum tensor-dependent Einstein's field equations

P. H. R. S. Moraes
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Abstract

The $f(R,T)$ gravity field equations depend generically on both the Ricci scalar $R$ and trace of the energy-momentum tensor $T$. Within the assumption of perfect fluids, the theory carries an arbitrariness regarding the choice of the matter lagrangian density $\mathcal{L}$, not uniquely defined. Such an arbitrariness can be evaded by working with the trace of the theory field equations. From such an equation, one can obtain a form for $\mathcal{L}$, which does not carry the arbitrariness. The obtained form for $\mathcal{L}$ shows that the $f(R,T)$ gravity is unimodular. A new version of the theory is, therefore, presented and forthcoming applications are expected.

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P. H. R. S. Moraes. 2019-07-10. The trace of the trace of the energy-momentum tensor-dependent Einstein's field equations. https://doi.org/10.1140/epjc%2Fs10052-019-7195-4

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